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// 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.
#ifndef ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_
#define ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_
#include <atomic>
#include <cassert>
#include <cstdint>
#include <utility>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#if defined(_MSC_VER) && !defined(__clang__)
#define ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT 0
#else
#define ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT 1
#endif
#if defined(_MSC_VER)
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 0
#else
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 1
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
template <typename T>
class AtomicHook;
// To workaround AtomicHook not being constant-initializable on some platforms,
// prefer to annotate instances with `ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES`
// instead of `ABSL_CONST_INIT`.
#if ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
#define ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES ABSL_CONST_INIT
#else
#define ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
#endif
// `AtomicHook` is a helper class, templatized on a raw function pointer type,
// for implementing Abseil customization hooks. It is a callable object that
// dispatches to the registered hook. Objects of type `AtomicHook` must have
// static or thread storage duration.
//
// A default constructed object performs a no-op (and returns a default
// constructed object) if no hook has been registered.
//
// Hooks can be pre-registered via constant initialization, for example:
//
// ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static AtomicHook<void(*)()>
// my_hook(DefaultAction);
//
// and then changed at runtime via a call to `Store()`.
//
// Reads and writes guarantee memory_order_acquire/memory_order_release
// semantics.
template <typename ReturnType, typename... Args>
class AtomicHook<ReturnType (*)(Args...)> {
public:
using FnPtr = ReturnType (*)(Args...);
// Constructs an object that by default performs a no-op (and
// returns a default constructed object) when no hook as been registered.
constexpr AtomicHook() : AtomicHook(DummyFunction) {}
// Constructs an object that by default dispatches to/returns the
// pre-registered default_fn when no hook has been registered at runtime.
#if ABSL_HAVE_WORKING_ATOMIC_POINTER && ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
explicit constexpr AtomicHook(FnPtr default_fn)
: hook_(default_fn), default_fn_(default_fn) {}
#elif ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
explicit constexpr AtomicHook(FnPtr default_fn)
: hook_(kUninitialized), default_fn_(default_fn) {}
#else
// As of January 2020, on all known versions of MSVC this constructor runs in
// the global constructor sequence. If `Store()` is called by a dynamic
// initializer, we want to preserve the value, even if this constructor runs
// after the call to `Store()`. If not, `hook_` will be
// zero-initialized by the linker and we have no need to set it.
// https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html
explicit constexpr AtomicHook(FnPtr default_fn)
: /* hook_(deliberately omitted), */ default_fn_(default_fn) {
static_assert(kUninitialized == 0, "here we rely on zero-initialization");
}
#endif
// Stores the provided function pointer as the value for this hook.
//
// This is intended to be called once. Multiple calls are legal only if the
// same function pointer is provided for each call. The store is implemented
// as a memory_order_release operation, and read accesses are implemented as
// memory_order_acquire.
void Store(FnPtr fn) {
bool success = DoStore(fn);
static_cast<void>(success);
assert(success);
}
// Invokes the registered callback. If no callback has yet been registered, a
// default-constructed object of the appropriate type is returned instead.
template <typename... CallArgs>
ReturnType operator()(CallArgs&&... args) const {
return DoLoad()(std::forward<CallArgs>(args)...);
}
// Returns the registered callback, or nullptr if none has been registered.
// Useful if client code needs to conditionalize behavior based on whether a
// callback was registered.
//
// Note that atomic_hook.Load()() and atomic_hook() have different semantics:
// operator()() will perform a no-op if no callback was registered, while
// Load()() will dereference a null function pointer. Prefer operator()() to
// Load()() unless you must conditionalize behavior on whether a hook was
// registered.
FnPtr Load() const {
FnPtr ptr = DoLoad();
return (ptr == DummyFunction) ? nullptr : ptr;
}
private:
static ReturnType DummyFunction(Args...) {
return ReturnType();
}
// Current versions of MSVC (as of September 2017) have a broken
// implementation of std::atomic<T*>: Its constructor attempts to do the
// equivalent of a reinterpret_cast in a constexpr context, which is not
// allowed.
//
// This causes an issue when building with LLVM under Windows. To avoid this,
// we use a less-efficient, intptr_t-based implementation on Windows.
#if ABSL_HAVE_WORKING_ATOMIC_POINTER
// Return the stored value, or DummyFunction if no value has been stored.
FnPtr DoLoad() const { return hook_.load(std::memory_order_acquire); }
// Store the given value. Returns false if a different value was already
// stored to this object.
bool DoStore(FnPtr fn) {
assert(fn);
FnPtr expected = default_fn_;
const bool store_succeeded = hook_.compare_exchange_strong(
expected, fn, std::memory_order_acq_rel, std::memory_order_acquire);
const bool same_value_already_stored = (expected == fn);
return store_succeeded || same_value_already_stored;
}
std::atomic<FnPtr> hook_;
#else // !ABSL_HAVE_WORKING_ATOMIC_POINTER
// Use a sentinel value unlikely to be the address of an actual function.
static constexpr intptr_t kUninitialized = 0;
static_assert(sizeof(intptr_t) >= sizeof(FnPtr),
"intptr_t can't contain a function pointer");
FnPtr DoLoad() const {
const intptr_t value = hook_.load(std::memory_order_acquire);
if (value == kUninitialized) {
return default_fn_;
}
return reinterpret_cast<FnPtr>(value);
}
bool DoStore(FnPtr fn) {
assert(fn);
const auto value = reinterpret_cast<intptr_t>(fn);
intptr_t expected = kUninitialized;
const bool store_succeeded = hook_.compare_exchange_strong(
expected, value, std::memory_order_acq_rel, std::memory_order_acquire);
const bool same_value_already_stored = (expected == value);
return store_succeeded || same_value_already_stored;
}
std::atomic<intptr_t> hook_;
#endif
const FnPtr default_fn_;
};
#undef ABSL_HAVE_WORKING_ATOMIC_POINTER
#undef ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_

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// 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.
#include "absl/base/internal/atomic_hook.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/attributes.h"
#include "absl/base/internal/atomic_hook_test_helper.h"
namespace {
using ::testing::Eq;
int value = 0;
void TestHook(int x) { value = x; }
TEST(AtomicHookTest, NoDefaultFunction) {
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static absl::base_internal::AtomicHook<
void (*)(int)>
hook;
value = 0;
// Test the default DummyFunction.
EXPECT_TRUE(hook.Load() == nullptr);
EXPECT_EQ(value, 0);
hook(1);
EXPECT_EQ(value, 0);
// Test a stored hook.
hook.Store(TestHook);
EXPECT_TRUE(hook.Load() == TestHook);
EXPECT_EQ(value, 0);
hook(1);
EXPECT_EQ(value, 1);
// Calling Store() with the same hook should not crash.
hook.Store(TestHook);
EXPECT_TRUE(hook.Load() == TestHook);
EXPECT_EQ(value, 1);
hook(2);
EXPECT_EQ(value, 2);
}
TEST(AtomicHookTest, WithDefaultFunction) {
// Set the default value to TestHook at compile-time.
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static absl::base_internal::AtomicHook<
void (*)(int)>
hook(TestHook);
value = 0;
// Test the default value is TestHook.
EXPECT_TRUE(hook.Load() == TestHook);
EXPECT_EQ(value, 0);
hook(1);
EXPECT_EQ(value, 1);
// Calling Store() with the same hook should not crash.
hook.Store(TestHook);
EXPECT_TRUE(hook.Load() == TestHook);
EXPECT_EQ(value, 1);
hook(2);
EXPECT_EQ(value, 2);
}
ABSL_CONST_INIT int override_func_calls = 0;
void OverrideFunc() { override_func_calls++; }
static struct OverrideInstaller {
OverrideInstaller() { absl::atomic_hook_internal::func.Store(OverrideFunc); }
} override_installer;
TEST(AtomicHookTest, DynamicInitFromAnotherTU) {
// MSVC 14.2 doesn't do constexpr static init correctly; in particular it
// tends to sequence static init (i.e. defaults) of `AtomicHook` objects
// after their dynamic init (i.e. overrides), overwriting whatever value was
// written during dynamic init. This regression test validates the fix.
// https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html
EXPECT_THAT(absl::atomic_hook_internal::default_func_calls, Eq(0));
EXPECT_THAT(override_func_calls, Eq(0));
absl::atomic_hook_internal::func();
EXPECT_THAT(absl::atomic_hook_internal::default_func_calls, Eq(0));
EXPECT_THAT(override_func_calls, Eq(1));
EXPECT_THAT(absl::atomic_hook_internal::func.Load(), Eq(OverrideFunc));
}
} // namespace

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// 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/atomic_hook_test_helper.h"
#include "absl/base/attributes.h"
#include "absl/base/internal/atomic_hook.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace atomic_hook_internal {
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES absl::base_internal::AtomicHook<VoidF>
func(DefaultFunc);
ABSL_CONST_INIT int default_func_calls = 0;
void DefaultFunc() { default_func_calls++; }
void RegisterFunc(VoidF f) { func.Store(f); }
} // namespace atomic_hook_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
#ifndef ABSL_BASE_INTERNAL_ATOMIC_HOOK_TEST_HELPER_H_
#define ABSL_BASE_INTERNAL_ATOMIC_HOOK_TEST_HELPER_H_
#include "absl/base/internal/atomic_hook.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace atomic_hook_internal {
using VoidF = void (*)();
extern absl::base_internal::AtomicHook<VoidF> func;
extern int default_func_calls;
void DefaultFunc();
void RegisterFunc(VoidF func);
} // namespace atomic_hook_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_ATOMIC_HOOK_TEST_HELPER_H_

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// 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.
#include <iostream>
#include "absl/base/internal/thread_identity.h"
int main() {
auto* tid = absl::base_internal::CurrentThreadIdentityIfPresent();
// Make sure the above call can't be optimized out
std::cout << (void*)tid << std::endl;
}

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// 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.
// The implementation of CycleClock::Frequency.
//
// NOTE: only i386 and x86_64 have been well tested.
// PPC, sparc, alpha, and ia64 are based on
// http://peter.kuscsik.com/wordpress/?p=14
// with modifications by m3b. See also
// https://setisvn.ssl.berkeley.edu/svn/lib/fftw-3.0.1/kernel/cycle.h
#include "absl/base/internal/cycleclock.h"
#include <atomic>
#include <chrono> // NOLINT(build/c++11)
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/unscaledcycleclock.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if ABSL_USE_UNSCALED_CYCLECLOCK
#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
constexpr int32_t CycleClock::kShift;
constexpr double CycleClock::kFrequencyScale;
#endif
ABSL_CONST_INIT std::atomic<CycleClockSourceFunc>
CycleClock::cycle_clock_source_{nullptr};
void CycleClockSource::Register(CycleClockSourceFunc source) {
// Corresponds to the load(std::memory_order_acquire) in LoadCycleClockSource.
CycleClock::cycle_clock_source_.store(source, std::memory_order_release);
}
#ifdef _WIN32
int64_t CycleClock::Now() {
auto fn = LoadCycleClockSource();
if (fn == nullptr) {
return base_internal::UnscaledCycleClock::Now() >> kShift;
}
return fn() >> kShift;
}
#endif
#else
int64_t CycleClock::Now() {
return std::chrono::duration_cast<std::chrono::nanoseconds>(
std::chrono::steady_clock::now().time_since_epoch())
.count();
}
double CycleClock::Frequency() {
return 1e9;
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// 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.
//
// -----------------------------------------------------------------------------
// File: cycleclock.h
// -----------------------------------------------------------------------------
//
// This header file defines a `CycleClock`, which yields the value and frequency
// of a cycle counter that increments at a rate that is approximately constant.
//
// NOTE:
//
// The cycle counter frequency is not necessarily related to the core clock
// frequency and should not be treated as such. That is, `CycleClock` cycles are
// not necessarily "CPU cycles" and code should not rely on that behavior, even
// if experimentally observed.
//
// An arbitrary offset may have been added to the counter at power on.
//
// On some platforms, the rate and offset of the counter may differ
// slightly when read from different CPUs of a multiprocessor. Usually,
// we try to ensure that the operating system adjusts values periodically
// so that values agree approximately. If you need stronger guarantees,
// consider using alternate interfaces.
//
// The CPU is not required to maintain the ordering of a cycle counter read
// with respect to surrounding instructions.
#ifndef ABSL_BASE_INTERNAL_CYCLECLOCK_H_
#define ABSL_BASE_INTERNAL_CYCLECLOCK_H_
#include <atomic>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/cycleclock_config.h"
#include "absl/base/internal/unscaledcycleclock.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
using CycleClockSourceFunc = int64_t (*)();
// -----------------------------------------------------------------------------
// CycleClock
// -----------------------------------------------------------------------------
class CycleClock {
public:
// CycleClock::Now()
//
// Returns the value of a cycle counter that counts at a rate that is
// approximately constant.
static int64_t Now();
// CycleClock::Frequency()
//
// Returns the amount by which `CycleClock::Now()` increases per second. Note
// that this value may not necessarily match the core CPU clock frequency.
static double Frequency();
private:
#if ABSL_USE_UNSCALED_CYCLECLOCK
static CycleClockSourceFunc LoadCycleClockSource();
static constexpr int32_t kShift = kCycleClockShift;
static constexpr double kFrequencyScale = kCycleClockFrequencyScale;
ABSL_CONST_INIT static std::atomic<CycleClockSourceFunc> cycle_clock_source_;
#endif // ABSL_USE_UNSCALED_CYCLECLOC
CycleClock() = delete; // no instances
CycleClock(const CycleClock&) = delete;
CycleClock& operator=(const CycleClock&) = delete;
friend class CycleClockSource;
};
class CycleClockSource {
private:
// CycleClockSource::Register()
//
// Register a function that provides an alternate source for the unscaled CPU
// cycle count value. The source function must be async signal safe, must not
// call CycleClock::Now(), and must have a frequency that matches that of the
// unscaled clock used by CycleClock. A nullptr value resets CycleClock to use
// the default source.
static void Register(CycleClockSourceFunc source);
};
#if ABSL_USE_UNSCALED_CYCLECLOCK
inline CycleClockSourceFunc CycleClock::LoadCycleClockSource() {
#if !defined(__x86_64__)
// Optimize for the common case (no callback) by first doing a relaxed load;
// this is significantly faster on non-x86 platforms.
if (cycle_clock_source_.load(std::memory_order_relaxed) == nullptr) {
return nullptr;
}
#endif // !defined(__x86_64__)
// This corresponds to the store(std::memory_order_release) in
// CycleClockSource::Register, and makes sure that any updates made prior to
// registering the callback are visible to this thread before the callback
// is invoked.
return cycle_clock_source_.load(std::memory_order_acquire);
}
// Accessing globals in inlined code in Window DLLs is problematic.
#ifndef _WIN32
inline int64_t CycleClock::Now() {
auto fn = LoadCycleClockSource();
if (fn == nullptr) {
return base_internal::UnscaledCycleClock::Now() >> kShift;
}
return fn() >> kShift;
}
#endif
inline double CycleClock::Frequency() {
return kFrequencyScale * base_internal::UnscaledCycleClock::Frequency();
}
#endif // ABSL_USE_UNSCALED_CYCLECLOCK
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_CYCLECLOCK_H_

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// Copyright 2022 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_CYCLECLOCK_CONFIG_H_
#define ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_
#include <cstdint>
#include "absl/base/config.h"
#include "absl/base/internal/inline_variable.h"
#include "absl/base/internal/unscaledcycleclock_config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if ABSL_USE_UNSCALED_CYCLECLOCK
#ifdef NDEBUG
#ifdef ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
// Not debug mode and the UnscaledCycleClock frequency is the CPU
// frequency. Scale the CycleClock to prevent overflow if someone
// tries to represent the time as cycles since the Unix epoch.
ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 1);
#else
// Not debug mode and the UnscaledCycleClock isn't operating at the
// raw CPU frequency. There is no need to do any scaling, so don't
// needlessly sacrifice precision.
ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 0);
#endif
#else // NDEBUG
// In debug mode use a different shift to discourage depending on a
// particular shift value.
ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 2);
#endif // NDEBUG
ABSL_INTERNAL_INLINE_CONSTEXPR(double, kCycleClockFrequencyScale,
1.0 / (1 << kCycleClockShift));
#endif // ABSL_USE_UNSCALED_CYCLECLOC
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_

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// 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.
//
// Functions for directly invoking mmap() via syscall, avoiding the case where
// mmap() has been locally overridden.
#ifndef ABSL_BASE_INTERNAL_DIRECT_MMAP_H_
#define ABSL_BASE_INTERNAL_DIRECT_MMAP_H_
#include "absl/base/config.h"
#ifdef ABSL_HAVE_MMAP
#include <sys/mman.h>
#ifdef __linux__
#include <sys/types.h>
#ifdef __BIONIC__
#include <sys/syscall.h>
#else
#include <syscall.h>
#endif
#include <linux/unistd.h>
#include <unistd.h>
#include <cerrno>
#include <cstdarg>
#include <cstdint>
#ifdef __mips__
// Include definitions of the ABI currently in use.
#if defined(__BIONIC__) || !defined(__GLIBC__)
// Android doesn't have sgidefs.h, but does have asm/sgidefs.h, which has the
// definitions we need.
#include <asm/sgidefs.h>
#else
#include <sgidefs.h>
#endif // __BIONIC__ || !__GLIBC__
#endif // __mips__
// SYS_mmap and SYS_munmap are not defined in Android.
#ifdef __BIONIC__
extern "C" void* __mmap2(void*, size_t, int, int, int, size_t);
#if defined(__NR_mmap) && !defined(SYS_mmap)
#define SYS_mmap __NR_mmap
#endif
#ifndef SYS_munmap
#define SYS_munmap __NR_munmap
#endif
#endif // __BIONIC__
#if defined(__NR_mmap2) && !defined(SYS_mmap2)
#define SYS_mmap2 __NR_mmap2
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Platform specific logic extracted from
// https://chromium.googlesource.com/linux-syscall-support/+/master/linux_syscall_support.h
inline void* DirectMmap(void* start, size_t length, int prot, int flags, int fd,
off_t offset) noexcept {
#if defined(__i386__) || defined(__ARM_ARCH_3__) || defined(__ARM_EABI__) || \
defined(__m68k__) || defined(__sh__) || \
(defined(__hppa__) && !defined(__LP64__)) || \
(defined(__mips__) && _MIPS_SIM == _MIPS_SIM_ABI32) || \
(defined(__PPC__) && !defined(__PPC64__)) || \
(defined(__riscv) && __riscv_xlen == 32) || \
(defined(__s390__) && !defined(__s390x__)) || \
(defined(__sparc__) && !defined(__arch64__))
// On these architectures, implement mmap with mmap2.
static int pagesize = 0;
if (pagesize == 0) {
#if defined(__wasm__) || defined(__asmjs__)
pagesize = getpagesize();
#else
pagesize = sysconf(_SC_PAGESIZE);
#endif
}
if (offset < 0 || offset % pagesize != 0) {
errno = EINVAL;
return MAP_FAILED;
}
#ifdef __BIONIC__
// SYS_mmap2 has problems on Android API level <= 16.
// Workaround by invoking __mmap2() instead.
return __mmap2(start, length, prot, flags, fd,
static_cast<size_t>(offset / pagesize));
#else
return reinterpret_cast<void*>(
syscall(SYS_mmap2, start, length, prot, flags, fd,
static_cast<unsigned long>(offset / pagesize))); // NOLINT
#endif
#elif defined(__s390x__)
// On s390x, mmap() arguments are passed in memory.
unsigned long buf[6] = {reinterpret_cast<unsigned long>(start), // NOLINT
static_cast<unsigned long>(length), // NOLINT
static_cast<unsigned long>(prot), // NOLINT
static_cast<unsigned long>(flags), // NOLINT
static_cast<unsigned long>(fd), // NOLINT
static_cast<unsigned long>(offset)}; // NOLINT
return reinterpret_cast<void*>(syscall(SYS_mmap, buf));
#elif defined(__x86_64__)
// The x32 ABI has 32 bit longs, but the syscall interface is 64 bit.
// We need to explicitly cast to an unsigned 64 bit type to avoid implicit
// sign extension. We can't cast pointers directly because those are
// 32 bits, and gcc will dump ugly warnings about casting from a pointer
// to an integer of a different size. We also need to make sure __off64_t
// isn't truncated to 32-bits under x32.
#define MMAP_SYSCALL_ARG(x) ((uint64_t)(uintptr_t)(x))
return reinterpret_cast<void*>(
syscall(SYS_mmap, MMAP_SYSCALL_ARG(start), MMAP_SYSCALL_ARG(length),
MMAP_SYSCALL_ARG(prot), MMAP_SYSCALL_ARG(flags),
MMAP_SYSCALL_ARG(fd), static_cast<uint64_t>(offset)));
#undef MMAP_SYSCALL_ARG
#else // Remaining 64-bit aritectures.
static_assert(sizeof(unsigned long) == 8, "Platform is not 64-bit");
return reinterpret_cast<void*>(
syscall(SYS_mmap, start, length, prot, flags, fd, offset));
#endif
}
inline int DirectMunmap(void* start, size_t length) {
return static_cast<int>(syscall(SYS_munmap, start, length));
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#else // !__linux__
// For non-linux platforms where we have mmap, just dispatch directly to the
// actual mmap()/munmap() methods.
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
inline void* DirectMmap(void* start, size_t length, int prot, int flags, int fd,
off_t offset) {
return mmap(start, length, prot, flags, fd, offset);
}
inline int DirectMunmap(void* start, size_t length) {
return munmap(start, length);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // __linux__
#endif // ABSL_HAVE_MMAP
#endif // ABSL_BASE_INTERNAL_DIRECT_MMAP_H_

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@ -0,0 +1,398 @@
// 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.
// This file defines dynamic annotations for use with dynamic analysis tool
// such as valgrind, PIN, etc.
//
// Dynamic annotation is a source code annotation that affects the generated
// code (that is, the annotation is not a comment). Each such annotation is
// attached to a particular instruction and/or to a particular object (address)
// in the program.
//
// The annotations that should be used by users are macros in all upper-case
// (e.g., ANNOTATE_THREAD_NAME).
//
// Actual implementation of these macros may differ depending on the dynamic
// analysis tool being used.
//
// This file supports the following configurations:
// - Dynamic Annotations enabled (with static thread-safety warnings disabled).
// In this case, macros expand to functions implemented by Thread Sanitizer,
// when building with TSan. When not provided an external implementation,
// dynamic_annotations.cc provides no-op implementations.
//
// - Static Clang thread-safety warnings enabled.
// When building with a Clang compiler that supports thread-safety warnings,
// a subset of annotations can be statically-checked at compile-time. We
// expand these macros to static-inline functions that can be analyzed for
// thread-safety, but afterwards elided when building the final binary.
//
// - All annotations are disabled.
// If neither Dynamic Annotations nor Clang thread-safety warnings are
// enabled, then all annotation-macros expand to empty.
#ifndef ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_
#define ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_
#include <stddef.h>
#include "absl/base/config.h"
// -------------------------------------------------------------------------
// Decide which features are enabled
#ifndef DYNAMIC_ANNOTATIONS_ENABLED
#define DYNAMIC_ANNOTATIONS_ENABLED 0
#endif
#if defined(__clang__) && !defined(SWIG)
#define ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED 1
#endif
#if DYNAMIC_ANNOTATIONS_ENABLED != 0
#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 1
#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED 0
#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED 1
#else
#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 0
#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 0
#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 0
// Clang provides limited support for static thread-safety analysis through a
// feature called Annotalysis. We configure macro-definitions according to
// whether Annotalysis support is available. When running in opt-mode, GCC
// will issue a warning, if these attributes are compiled. Only include them
// when compiling using Clang.
// ANNOTALYSIS_ENABLED == 1 when IGNORE_READ_ATTRIBUTE_ENABLED == 1
#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED \
defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
// Read/write annotations are enabled in Annotalysis mode; disabled otherwise.
#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED \
ABSL_INTERNAL_ANNOTALYSIS_ENABLED
#endif
// Memory annotations are also made available to LLVM's Memory Sanitizer
#if defined(ABSL_HAVE_MEMORY_SANITIZER) && !defined(__native_client__)
#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 1
#endif
#ifndef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 0
#endif
#ifdef __cplusplus
#define ABSL_INTERNAL_BEGIN_EXTERN_C extern "C" {
#define ABSL_INTERNAL_END_EXTERN_C } // extern "C"
#define ABSL_INTERNAL_GLOBAL_SCOPED(F) ::F
#define ABSL_INTERNAL_STATIC_INLINE inline
#else
#define ABSL_INTERNAL_BEGIN_EXTERN_C // empty
#define ABSL_INTERNAL_END_EXTERN_C // empty
#define ABSL_INTERNAL_GLOBAL_SCOPED(F) F
#define ABSL_INTERNAL_STATIC_INLINE static inline
#endif
// -------------------------------------------------------------------------
// Define race annotations.
#if ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 1
// -------------------------------------------------------------
// Annotations that suppress errors. It is usually better to express the
// program's synchronization using the other annotations, but these can be used
// when all else fails.
// Report that we may have a benign race at `pointer`, with size
// "sizeof(*(pointer))". `pointer` must be a non-void* pointer. Insert at the
// point where `pointer` has been allocated, preferably close to the point
// where the race happens. See also ANNOTATE_BENIGN_RACE_STATIC.
#define ANNOTATE_BENIGN_RACE(pointer, description) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized) \
(__FILE__, __LINE__, pointer, sizeof(*(pointer)), description)
// Same as ANNOTATE_BENIGN_RACE(`address`, `description`), but applies to
// the memory range [`address`, `address`+`size`).
#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized) \
(__FILE__, __LINE__, address, size, description)
// Enable (`enable`!=0) or disable (`enable`==0) race detection for all threads.
// This annotation could be useful if you want to skip expensive race analysis
// during some period of program execution, e.g. during initialization.
#define ANNOTATE_ENABLE_RACE_DETECTION(enable) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateEnableRaceDetection) \
(__FILE__, __LINE__, enable)
// -------------------------------------------------------------
// Annotations useful for debugging.
// Report the current thread `name` to a race detector.
#define ANNOTATE_THREAD_NAME(name) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateThreadName)(__FILE__, __LINE__, name)
// -------------------------------------------------------------
// Annotations useful when implementing locks. They are not normally needed by
// modules that merely use locks. The `lock` argument is a pointer to the lock
// object.
// Report that a lock has been created at address `lock`.
#define ANNOTATE_RWLOCK_CREATE(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreate)(__FILE__, __LINE__, lock)
// Report that a linker initialized lock has been created at address `lock`.
#ifdef ABSL_HAVE_THREAD_SANITIZER
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreateStatic) \
(__FILE__, __LINE__, lock)
#else
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) ANNOTATE_RWLOCK_CREATE(lock)
#endif
// Report that the lock at address `lock` is about to be destroyed.
#define ANNOTATE_RWLOCK_DESTROY(lock) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockDestroy)(__FILE__, __LINE__, lock)
// Report that the lock at address `lock` has been acquired.
// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockAcquired) \
(__FILE__, __LINE__, lock, is_w)
// Report that the lock at address `lock` is about to be released.
// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockReleased) \
(__FILE__, __LINE__, lock, is_w)
// Apply ANNOTATE_BENIGN_RACE_SIZED to a static variable `static_var`.
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description) \
namespace { \
class static_var##_annotator { \
public: \
static_var##_annotator() { \
ANNOTATE_BENIGN_RACE_SIZED(&static_var, sizeof(static_var), \
#static_var ": " description); \
} \
}; \
static static_var##_annotator the##static_var##_annotator; \
} // namespace
#else // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 0
#define ANNOTATE_RWLOCK_CREATE(lock) // empty
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) // empty
#define ANNOTATE_RWLOCK_DESTROY(lock) // empty
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) // empty
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) // empty
#define ANNOTATE_BENIGN_RACE(address, description) // empty
#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) // empty
#define ANNOTATE_THREAD_NAME(name) // empty
#define ANNOTATE_ENABLE_RACE_DETECTION(enable) // empty
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description) // empty
#endif // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
// -------------------------------------------------------------------------
// Define memory annotations.
#if ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 1
#include <sanitizer/msan_interface.h>
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
__msan_unpoison(address, size)
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
__msan_allocated_memory(address, size)
#else // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 0
#if DYNAMIC_ANNOTATIONS_ENABLED == 1
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
do { \
(void)(address); \
(void)(size); \
} while (0)
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
do { \
(void)(address); \
(void)(size); \
} while (0)
#else
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) // empty
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) // empty
#endif
#endif // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
// -------------------------------------------------------------------------
// Define IGNORE_READS_BEGIN/_END attributes.
#if defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE \
__attribute((exclusive_lock_function("*")))
#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE \
__attribute((unlock_function("*")))
#else // !defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE // empty
#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE // empty
#endif // defined(ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED)
// -------------------------------------------------------------------------
// Define IGNORE_READS_BEGIN/_END annotations.
#if ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED == 1
// Request the analysis tool to ignore all reads in the current thread until
// ANNOTATE_IGNORE_READS_END is called. Useful to ignore intentional racey
// reads, while still checking other reads and all writes.
// See also ANNOTATE_UNPROTECTED_READ.
#define ANNOTATE_IGNORE_READS_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsBegin)(__FILE__, __LINE__)
// Stop ignoring reads.
#define ANNOTATE_IGNORE_READS_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsEnd)(__FILE__, __LINE__)
#elif defined(ABSL_INTERNAL_ANNOTALYSIS_ENABLED)
// When Annotalysis is enabled without Dynamic Annotations, the use of
// static-inline functions allows the annotations to be read at compile-time,
// while still letting the compiler elide the functions from the final build.
//
// TODO(delesley) -- The exclusive lock here ignores writes as well, but
// allows IGNORE_READS_AND_WRITES to work properly.
#define ANNOTATE_IGNORE_READS_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsBegin)()
#define ANNOTATE_IGNORE_READS_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsEnd)()
#else
#define ANNOTATE_IGNORE_READS_BEGIN() // empty
#define ANNOTATE_IGNORE_READS_END() // empty
#endif
// -------------------------------------------------------------------------
// Define IGNORE_WRITES_BEGIN/_END annotations.
#if ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED == 1
// Similar to ANNOTATE_IGNORE_READS_BEGIN, but ignore writes instead.
#define ANNOTATE_IGNORE_WRITES_BEGIN() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesBegin)(__FILE__, __LINE__)
// Stop ignoring writes.
#define ANNOTATE_IGNORE_WRITES_END() \
ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesEnd)(__FILE__, __LINE__)
#else
#define ANNOTATE_IGNORE_WRITES_BEGIN() // empty
#define ANNOTATE_IGNORE_WRITES_END() // empty
#endif
// -------------------------------------------------------------------------
// Define the ANNOTATE_IGNORE_READS_AND_WRITES_* annotations using the more
// primitive annotations defined above.
//
// Instead of doing
// ANNOTATE_IGNORE_READS_BEGIN();
// ... = x;
// ANNOTATE_IGNORE_READS_END();
// one can use
// ... = ANNOTATE_UNPROTECTED_READ(x);
#if defined(ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED)
// Start ignoring all memory accesses (both reads and writes).
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
do { \
ANNOTATE_IGNORE_READS_BEGIN(); \
ANNOTATE_IGNORE_WRITES_BEGIN(); \
} while (0)
// Stop ignoring both reads and writes.
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() \
do { \
ANNOTATE_IGNORE_WRITES_END(); \
ANNOTATE_IGNORE_READS_END(); \
} while (0)
#ifdef __cplusplus
// ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
#define ANNOTATE_UNPROTECTED_READ(x) \
absl::base_internal::AnnotateUnprotectedRead(x)
#endif
#else
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() // empty
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() // empty
#define ANNOTATE_UNPROTECTED_READ(x) (x)
#endif
// -------------------------------------------------------------------------
// Address sanitizer annotations
#ifdef ABSL_HAVE_ADDRESS_SANITIZER
// Describe the current state of a contiguous container such as e.g.
// std::vector or std::string. For more details see
// sanitizer/common_interface_defs.h, which is provided by the compiler.
#include <sanitizer/common_interface_defs.h>
#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) \
__sanitizer_annotate_contiguous_container(beg, end, old_mid, new_mid)
#define ADDRESS_SANITIZER_REDZONE(name) \
struct { \
char x[8] __attribute__((aligned(8))); \
} name
#else
#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
#define ADDRESS_SANITIZER_REDZONE(name) static_assert(true, "")
#endif // ABSL_HAVE_ADDRESS_SANITIZER
// -------------------------------------------------------------------------
// Undefine the macros intended only for this file.
#undef ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_ANNOTALYSIS_ENABLED
#undef ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED
#undef ABSL_INTERNAL_BEGIN_EXTERN_C
#undef ABSL_INTERNAL_END_EXTERN_C
#undef ABSL_INTERNAL_STATIC_INLINE
#endif // ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_

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@ -0,0 +1,283 @@
// 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.
//
#ifndef ABSL_BASE_INTERNAL_ENDIAN_H_
#define ABSL_BASE_INTERNAL_ENDIAN_H_
#include <cstdint>
#include <cstdlib>
#include "absl/base/casts.h"
#include "absl/base/config.h"
#include "absl/base/internal/unaligned_access.h"
#include "absl/base/nullability.h"
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
inline uint64_t gbswap_64(uint64_t host_int) {
#if ABSL_HAVE_BUILTIN(__builtin_bswap64) || defined(__GNUC__)
return __builtin_bswap64(host_int);
#elif defined(_MSC_VER)
return _byteswap_uint64(host_int);
#else
return (((host_int & uint64_t{0xFF}) << 56) |
((host_int & uint64_t{0xFF00}) << 40) |
((host_int & uint64_t{0xFF0000}) << 24) |
((host_int & uint64_t{0xFF000000}) << 8) |
((host_int & uint64_t{0xFF00000000}) >> 8) |
((host_int & uint64_t{0xFF0000000000}) >> 24) |
((host_int & uint64_t{0xFF000000000000}) >> 40) |
((host_int & uint64_t{0xFF00000000000000}) >> 56));
#endif
}
inline uint32_t gbswap_32(uint32_t host_int) {
#if ABSL_HAVE_BUILTIN(__builtin_bswap32) || defined(__GNUC__)
return __builtin_bswap32(host_int);
#elif defined(_MSC_VER)
return _byteswap_ulong(host_int);
#else
return (((host_int & uint32_t{0xFF}) << 24) |
((host_int & uint32_t{0xFF00}) << 8) |
((host_int & uint32_t{0xFF0000}) >> 8) |
((host_int & uint32_t{0xFF000000}) >> 24));
#endif
}
inline uint16_t gbswap_16(uint16_t host_int) {
#if ABSL_HAVE_BUILTIN(__builtin_bswap16) || defined(__GNUC__)
return __builtin_bswap16(host_int);
#elif defined(_MSC_VER)
return _byteswap_ushort(host_int);
#else
return (((host_int & uint16_t{0xFF}) << 8) |
((host_int & uint16_t{0xFF00}) >> 8));
#endif
}
#ifdef ABSL_IS_LITTLE_ENDIAN
// Portable definitions for htonl (host-to-network) and friends on little-endian
// architectures.
inline uint16_t ghtons(uint16_t x) { return gbswap_16(x); }
inline uint32_t ghtonl(uint32_t x) { return gbswap_32(x); }
inline uint64_t ghtonll(uint64_t x) { return gbswap_64(x); }
#elif defined ABSL_IS_BIG_ENDIAN
// Portable definitions for htonl (host-to-network) etc on big-endian
// architectures. These definitions are simpler since the host byte order is the
// same as network byte order.
inline uint16_t ghtons(uint16_t x) { return x; }
inline uint32_t ghtonl(uint32_t x) { return x; }
inline uint64_t ghtonll(uint64_t x) { return x; }
#else
#error \
"Unsupported byte order: Either ABSL_IS_BIG_ENDIAN or " \
"ABSL_IS_LITTLE_ENDIAN must be defined"
#endif // byte order
inline uint16_t gntohs(uint16_t x) { return ghtons(x); }
inline uint32_t gntohl(uint32_t x) { return ghtonl(x); }
inline uint64_t gntohll(uint64_t x) { return ghtonll(x); }
// Utilities to convert numbers between the current hosts's native byte
// order and little-endian byte order
//
// Load/Store methods are alignment safe
namespace little_endian {
// Conversion functions.
#ifdef ABSL_IS_LITTLE_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return x; }
inline uint16_t ToHost16(uint16_t x) { return x; }
inline uint32_t FromHost32(uint32_t x) { return x; }
inline uint32_t ToHost32(uint32_t x) { return x; }
inline uint64_t FromHost64(uint64_t x) { return x; }
inline uint64_t ToHost64(uint64_t x) { return x; }
inline constexpr bool IsLittleEndian() { return true; }
#elif defined ABSL_IS_BIG_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return gbswap_16(x); }
inline uint16_t ToHost16(uint16_t x) { return gbswap_16(x); }
inline uint32_t FromHost32(uint32_t x) { return gbswap_32(x); }
inline uint32_t ToHost32(uint32_t x) { return gbswap_32(x); }
inline uint64_t FromHost64(uint64_t x) { return gbswap_64(x); }
inline uint64_t ToHost64(uint64_t x) { return gbswap_64(x); }
inline constexpr bool IsLittleEndian() { return false; }
#endif /* ENDIAN */
inline uint8_t FromHost(uint8_t x) { return x; }
inline uint16_t FromHost(uint16_t x) { return FromHost16(x); }
inline uint32_t FromHost(uint32_t x) { return FromHost32(x); }
inline uint64_t FromHost(uint64_t x) { return FromHost64(x); }
inline uint8_t ToHost(uint8_t x) { return x; }
inline uint16_t ToHost(uint16_t x) { return ToHost16(x); }
inline uint32_t ToHost(uint32_t x) { return ToHost32(x); }
inline uint64_t ToHost(uint64_t x) { return ToHost64(x); }
inline int8_t FromHost(int8_t x) { return x; }
inline int16_t FromHost(int16_t x) {
return bit_cast<int16_t>(FromHost16(bit_cast<uint16_t>(x)));
}
inline int32_t FromHost(int32_t x) {
return bit_cast<int32_t>(FromHost32(bit_cast<uint32_t>(x)));
}
inline int64_t FromHost(int64_t x) {
return bit_cast<int64_t>(FromHost64(bit_cast<uint64_t>(x)));
}
inline int8_t ToHost(int8_t x) { return x; }
inline int16_t ToHost(int16_t x) {
return bit_cast<int16_t>(ToHost16(bit_cast<uint16_t>(x)));
}
inline int32_t ToHost(int32_t x) {
return bit_cast<int32_t>(ToHost32(bit_cast<uint32_t>(x)));
}
inline int64_t ToHost(int64_t x) {
return bit_cast<int64_t>(ToHost64(bit_cast<uint64_t>(x)));
}
// Functions to do unaligned loads and stores in little-endian order.
inline uint16_t Load16(absl::Nonnull<const void *> p) {
return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
}
inline void Store16(absl::Nonnull<void *> p, uint16_t v) {
ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v));
}
inline uint32_t Load32(absl::Nonnull<const void *> p) {
return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p));
}
inline void Store32(absl::Nonnull<void *> p, uint32_t v) {
ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v));
}
inline uint64_t Load64(absl::Nonnull<const void *> p) {
return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p));
}
inline void Store64(absl::Nonnull<void *> p, uint64_t v) {
ABSL_INTERNAL_UNALIGNED_STORE64(p, FromHost64(v));
}
} // namespace little_endian
// Utilities to convert numbers between the current hosts's native byte
// order and big-endian byte order (same as network byte order)
//
// Load/Store methods are alignment safe
namespace big_endian {
#ifdef ABSL_IS_LITTLE_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return gbswap_16(x); }
inline uint16_t ToHost16(uint16_t x) { return gbswap_16(x); }
inline uint32_t FromHost32(uint32_t x) { return gbswap_32(x); }
inline uint32_t ToHost32(uint32_t x) { return gbswap_32(x); }
inline uint64_t FromHost64(uint64_t x) { return gbswap_64(x); }
inline uint64_t ToHost64(uint64_t x) { return gbswap_64(x); }
inline constexpr bool IsLittleEndian() { return true; }
#elif defined ABSL_IS_BIG_ENDIAN
inline uint16_t FromHost16(uint16_t x) { return x; }
inline uint16_t ToHost16(uint16_t x) { return x; }
inline uint32_t FromHost32(uint32_t x) { return x; }
inline uint32_t ToHost32(uint32_t x) { return x; }
inline uint64_t FromHost64(uint64_t x) { return x; }
inline uint64_t ToHost64(uint64_t x) { return x; }
inline constexpr bool IsLittleEndian() { return false; }
#endif /* ENDIAN */
inline uint8_t FromHost(uint8_t x) { return x; }
inline uint16_t FromHost(uint16_t x) { return FromHost16(x); }
inline uint32_t FromHost(uint32_t x) { return FromHost32(x); }
inline uint64_t FromHost(uint64_t x) { return FromHost64(x); }
inline uint8_t ToHost(uint8_t x) { return x; }
inline uint16_t ToHost(uint16_t x) { return ToHost16(x); }
inline uint32_t ToHost(uint32_t x) { return ToHost32(x); }
inline uint64_t ToHost(uint64_t x) { return ToHost64(x); }
inline int8_t FromHost(int8_t x) { return x; }
inline int16_t FromHost(int16_t x) {
return bit_cast<int16_t>(FromHost16(bit_cast<uint16_t>(x)));
}
inline int32_t FromHost(int32_t x) {
return bit_cast<int32_t>(FromHost32(bit_cast<uint32_t>(x)));
}
inline int64_t FromHost(int64_t x) {
return bit_cast<int64_t>(FromHost64(bit_cast<uint64_t>(x)));
}
inline int8_t ToHost(int8_t x) { return x; }
inline int16_t ToHost(int16_t x) {
return bit_cast<int16_t>(ToHost16(bit_cast<uint16_t>(x)));
}
inline int32_t ToHost(int32_t x) {
return bit_cast<int32_t>(ToHost32(bit_cast<uint32_t>(x)));
}
inline int64_t ToHost(int64_t x) {
return bit_cast<int64_t>(ToHost64(bit_cast<uint64_t>(x)));
}
// Functions to do unaligned loads and stores in big-endian order.
inline uint16_t Load16(absl::Nonnull<const void *> p) {
return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
}
inline void Store16(absl::Nonnull<void *> p, uint16_t v) {
ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v));
}
inline uint32_t Load32(absl::Nonnull<const void *> p) {
return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p));
}
inline void Store32(absl::Nonnull<void *>p, uint32_t v) {
ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v));
}
inline uint64_t Load64(absl::Nonnull<const void *> p) {
return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p));
}
inline void Store64(absl::Nonnull<void *> p, uint64_t v) {
ABSL_INTERNAL_UNALIGNED_STORE64(p, FromHost64(v));
}
} // namespace big_endian
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_ENDIAN_H_

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// 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/endian.h"
#include <algorithm>
#include <cstdint>
#include <limits>
#include <random>
#include <vector>
#include "gtest/gtest.h"
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace {
const uint64_t kInitialNumber{0x0123456789abcdef};
const uint64_t k64Value{kInitialNumber};
const uint32_t k32Value{0x01234567};
const uint16_t k16Value{0x0123};
const int kNumValuesToTest = 1000000;
const int kRandomSeed = 12345;
#if defined(ABSL_IS_BIG_ENDIAN)
const uint64_t kInitialInNetworkOrder{kInitialNumber};
const uint64_t k64ValueLE{0xefcdab8967452301};
const uint32_t k32ValueLE{0x67452301};
const uint16_t k16ValueLE{0x2301};
const uint64_t k64ValueBE{kInitialNumber};
const uint32_t k32ValueBE{k32Value};
const uint16_t k16ValueBE{k16Value};
#elif defined(ABSL_IS_LITTLE_ENDIAN)
const uint64_t kInitialInNetworkOrder{0xefcdab8967452301};
const uint64_t k64ValueLE{kInitialNumber};
const uint32_t k32ValueLE{k32Value};
const uint16_t k16ValueLE{k16Value};
const uint64_t k64ValueBE{0xefcdab8967452301};
const uint32_t k32ValueBE{0x67452301};
const uint16_t k16ValueBE{0x2301};
#endif
std::vector<uint16_t> GenerateAllUint16Values() {
std::vector<uint16_t> result;
result.reserve(size_t{1} << (sizeof(uint16_t) * 8));
for (uint32_t i = std::numeric_limits<uint16_t>::min();
i <= std::numeric_limits<uint16_t>::max(); ++i) {
result.push_back(static_cast<uint16_t>(i));
}
return result;
}
template<typename T>
std::vector<T> GenerateRandomIntegers(size_t num_values_to_test) {
std::vector<T> result;
result.reserve(num_values_to_test);
std::mt19937_64 rng(kRandomSeed);
for (size_t i = 0; i < num_values_to_test; ++i) {
result.push_back(rng());
}
return result;
}
void ManualByteSwap(char* bytes, int length) {
if (length == 1)
return;
EXPECT_EQ(0, length % 2);
for (int i = 0; i < length / 2; ++i) {
int j = (length - 1) - i;
using std::swap;
swap(bytes[i], bytes[j]);
}
}
template<typename T>
inline T UnalignedLoad(const char* p) {
static_assert(
sizeof(T) == 1 || sizeof(T) == 2 || sizeof(T) == 4 || sizeof(T) == 8,
"Unexpected type size");
switch (sizeof(T)) {
case 1: return *reinterpret_cast<const T*>(p);
case 2:
return ABSL_INTERNAL_UNALIGNED_LOAD16(p);
case 4:
return ABSL_INTERNAL_UNALIGNED_LOAD32(p);
case 8:
return ABSL_INTERNAL_UNALIGNED_LOAD64(p);
default:
// Suppresses invalid "not all control paths return a value" on MSVC
return {};
}
}
template <typename T, typename ByteSwapper>
static void GBSwapHelper(const std::vector<T>& host_values_to_test,
const ByteSwapper& byte_swapper) {
// Test byte_swapper against a manual byte swap.
for (typename std::vector<T>::const_iterator it = host_values_to_test.begin();
it != host_values_to_test.end(); ++it) {
T host_value = *it;
char actual_value[sizeof(host_value)];
memcpy(actual_value, &host_value, sizeof(host_value));
byte_swapper(actual_value);
char expected_value[sizeof(host_value)];
memcpy(expected_value, &host_value, sizeof(host_value));
ManualByteSwap(expected_value, sizeof(host_value));
ASSERT_EQ(0, memcmp(actual_value, expected_value, sizeof(host_value)))
<< "Swap output for 0x" << std::hex << host_value << " does not match. "
<< "Expected: 0x" << UnalignedLoad<T>(expected_value) << "; "
<< "actual: 0x" << UnalignedLoad<T>(actual_value);
}
}
void Swap16(char* bytes) {
ABSL_INTERNAL_UNALIGNED_STORE16(
bytes, gbswap_16(ABSL_INTERNAL_UNALIGNED_LOAD16(bytes)));
}
void Swap32(char* bytes) {
ABSL_INTERNAL_UNALIGNED_STORE32(
bytes, gbswap_32(ABSL_INTERNAL_UNALIGNED_LOAD32(bytes)));
}
void Swap64(char* bytes) {
ABSL_INTERNAL_UNALIGNED_STORE64(
bytes, gbswap_64(ABSL_INTERNAL_UNALIGNED_LOAD64(bytes)));
}
TEST(EndianessTest, Uint16) {
GBSwapHelper(GenerateAllUint16Values(), &Swap16);
}
TEST(EndianessTest, Uint32) {
GBSwapHelper(GenerateRandomIntegers<uint32_t>(kNumValuesToTest), &Swap32);
}
TEST(EndianessTest, Uint64) {
GBSwapHelper(GenerateRandomIntegers<uint64_t>(kNumValuesToTest), &Swap64);
}
TEST(EndianessTest, ghtonll_gntohll) {
// Test that absl::ghtonl compiles correctly
uint32_t test = 0x01234567;
EXPECT_EQ(absl::gntohl(absl::ghtonl(test)), test);
uint64_t comp = absl::ghtonll(kInitialNumber);
EXPECT_EQ(comp, kInitialInNetworkOrder);
comp = absl::gntohll(kInitialInNetworkOrder);
EXPECT_EQ(comp, kInitialNumber);
// Test that htonll and ntohll are each others' inverse functions on a
// somewhat assorted batch of numbers. 37 is chosen to not be anything
// particularly nice base 2.
uint64_t value = 1;
for (int i = 0; i < 100; ++i) {
comp = absl::ghtonll(absl::gntohll(value));
EXPECT_EQ(value, comp);
comp = absl::gntohll(absl::ghtonll(value));
EXPECT_EQ(value, comp);
value *= 37;
}
}
TEST(EndianessTest, little_endian) {
// Check little_endian uint16_t.
uint64_t comp = little_endian::FromHost16(k16Value);
EXPECT_EQ(comp, k16ValueLE);
comp = little_endian::ToHost16(k16ValueLE);
EXPECT_EQ(comp, k16Value);
// Check little_endian uint32_t.
comp = little_endian::FromHost32(k32Value);
EXPECT_EQ(comp, k32ValueLE);
comp = little_endian::ToHost32(k32ValueLE);
EXPECT_EQ(comp, k32Value);
// Check little_endian uint64_t.
comp = little_endian::FromHost64(k64Value);
EXPECT_EQ(comp, k64ValueLE);
comp = little_endian::ToHost64(k64ValueLE);
EXPECT_EQ(comp, k64Value);
// Check little-endian Load and store functions.
uint16_t u16Buf;
uint32_t u32Buf;
uint64_t u64Buf;
little_endian::Store16(&u16Buf, k16Value);
EXPECT_EQ(u16Buf, k16ValueLE);
comp = little_endian::Load16(&u16Buf);
EXPECT_EQ(comp, k16Value);
little_endian::Store32(&u32Buf, k32Value);
EXPECT_EQ(u32Buf, k32ValueLE);
comp = little_endian::Load32(&u32Buf);
EXPECT_EQ(comp, k32Value);
little_endian::Store64(&u64Buf, k64Value);
EXPECT_EQ(u64Buf, k64ValueLE);
comp = little_endian::Load64(&u64Buf);
EXPECT_EQ(comp, k64Value);
}
TEST(EndianessTest, big_endian) {
// Check big-endian Load and store functions.
uint16_t u16Buf;
uint32_t u32Buf;
uint64_t u64Buf;
unsigned char buffer[10];
big_endian::Store16(&u16Buf, k16Value);
EXPECT_EQ(u16Buf, k16ValueBE);
uint64_t comp = big_endian::Load16(&u16Buf);
EXPECT_EQ(comp, k16Value);
big_endian::Store32(&u32Buf, k32Value);
EXPECT_EQ(u32Buf, k32ValueBE);
comp = big_endian::Load32(&u32Buf);
EXPECT_EQ(comp, k32Value);
big_endian::Store64(&u64Buf, k64Value);
EXPECT_EQ(u64Buf, k64ValueBE);
comp = big_endian::Load64(&u64Buf);
EXPECT_EQ(comp, k64Value);
big_endian::Store16(buffer + 1, k16Value);
EXPECT_EQ(u16Buf, k16ValueBE);
comp = big_endian::Load16(buffer + 1);
EXPECT_EQ(comp, k16Value);
big_endian::Store32(buffer + 1, k32Value);
EXPECT_EQ(u32Buf, k32ValueBE);
comp = big_endian::Load32(buffer + 1);
EXPECT_EQ(comp, k32Value);
big_endian::Store64(buffer + 1, k64Value);
EXPECT_EQ(u64Buf, k64ValueBE);
comp = big_endian::Load64(buffer + 1);
EXPECT_EQ(comp, k64Value);
}
} // namespace
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
#ifndef ABSL_BASE_INTERNAL_ERRNO_SAVER_H_
#define ABSL_BASE_INTERNAL_ERRNO_SAVER_H_
#include <cerrno>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// `ErrnoSaver` captures the value of `errno` upon construction and restores it
// upon deletion. It is used in low-level code and must be super fast. Do not
// add instrumentation, even in debug modes.
class ErrnoSaver {
public:
ErrnoSaver() : saved_errno_(errno) {}
~ErrnoSaver() { errno = saved_errno_; }
int operator()() const { return saved_errno_; }
private:
const int saved_errno_;
};
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_ERRNO_SAVER_H_

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// 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.
#include "absl/base/internal/errno_saver.h"
#include <cerrno>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/internal/strerror.h"
namespace {
using ::testing::Eq;
struct ErrnoPrinter {
int no;
};
std::ostream &operator<<(std::ostream &os, ErrnoPrinter ep) {
return os << absl::base_internal::StrError(ep.no) << " [" << ep.no << "]";
}
bool operator==(ErrnoPrinter one, ErrnoPrinter two) { return one.no == two.no; }
TEST(ErrnoSaverTest, Works) {
errno = EDOM;
{
absl::base_internal::ErrnoSaver errno_saver;
EXPECT_THAT(ErrnoPrinter{errno}, Eq(ErrnoPrinter{EDOM}));
errno = ERANGE;
EXPECT_THAT(ErrnoPrinter{errno}, Eq(ErrnoPrinter{ERANGE}));
EXPECT_THAT(ErrnoPrinter{errno_saver()}, Eq(ErrnoPrinter{EDOM}));
}
EXPECT_THAT(ErrnoPrinter{errno}, Eq(ErrnoPrinter{EDOM}));
}
} // namespace

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// 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/exception_safety_testing.h"
#ifdef ABSL_HAVE_EXCEPTIONS
#include "gtest/gtest.h"
#include "absl/meta/type_traits.h"
namespace testing {
exceptions_internal::NoThrowTag nothrow_ctor;
exceptions_internal::StrongGuaranteeTagType strong_guarantee;
exceptions_internal::ExceptionSafetyTestBuilder<> MakeExceptionSafetyTester() {
return {};
}
namespace exceptions_internal {
int countdown = -1;
ConstructorTracker* ConstructorTracker::current_tracker_instance_ = nullptr;
void MaybeThrow(absl::string_view msg, bool throw_bad_alloc) {
if (countdown-- == 0) {
if (throw_bad_alloc) throw TestBadAllocException(msg);
throw TestException(msg);
}
}
testing::AssertionResult FailureMessage(const TestException& e,
int countdown) noexcept {
return testing::AssertionFailure() << "Exception thrown from " << e.what();
}
std::string GetSpecString(TypeSpec spec) {
std::string out;
absl::string_view sep;
const auto append = [&](absl::string_view s) {
absl::StrAppend(&out, sep, s);
sep = " | ";
};
if (static_cast<bool>(TypeSpec::kNoThrowCopy & spec)) {
append("kNoThrowCopy");
}
if (static_cast<bool>(TypeSpec::kNoThrowMove & spec)) {
append("kNoThrowMove");
}
if (static_cast<bool>(TypeSpec::kNoThrowNew & spec)) {
append("kNoThrowNew");
}
return out;
}
std::string GetSpecString(AllocSpec spec) {
return static_cast<bool>(AllocSpec::kNoThrowAllocate & spec)
? "kNoThrowAllocate"
: "";
}
} // namespace exceptions_internal
} // namespace testing
#endif // ABSL_HAVE_EXCEPTIONS

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// 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.
// Testing utilities for ABSL types which throw exceptions.
#ifndef ABSL_BASE_INTERNAL_EXCEPTION_TESTING_H_
#define ABSL_BASE_INTERNAL_EXCEPTION_TESTING_H_
#include "gtest/gtest.h"
#include "absl/base/config.h"
// ABSL_BASE_INTERNAL_EXPECT_FAIL tests either for a specified thrown exception
// if exceptions are enabled, or for death with a specified text in the error
// message
#ifdef ABSL_HAVE_EXCEPTIONS
#define ABSL_BASE_INTERNAL_EXPECT_FAIL(expr, exception_t, text) \
EXPECT_THROW(expr, exception_t)
#elif defined(__ANDROID__)
// Android asserts do not log anywhere that gtest can currently inspect.
// So we expect exit, but cannot match the message.
#define ABSL_BASE_INTERNAL_EXPECT_FAIL(expr, exception_t, text) \
EXPECT_DEATH(expr, ".*")
#else
#define ABSL_BASE_INTERNAL_EXPECT_FAIL(expr, exception_t, text) \
EXPECT_DEATH_IF_SUPPORTED(expr, text)
#endif
#endif // ABSL_BASE_INTERNAL_EXCEPTION_TESTING_H_

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//
// Copyright 2020 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_FAST_TYPE_ID_H_
#define ABSL_BASE_INTERNAL_FAST_TYPE_ID_H_
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
template <typename Type>
struct FastTypeTag {
constexpr static char dummy_var = 0;
};
#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
template <typename Type>
constexpr char FastTypeTag<Type>::dummy_var;
#endif
// FastTypeId<Type>() evaluates at compile/link-time to a unique pointer for the
// passed-in type. These are meant to be good match for keys into maps or
// straight up comparisons.
using FastTypeIdType = const void*;
template <typename Type>
constexpr inline FastTypeIdType FastTypeId() {
return &FastTypeTag<Type>::dummy_var;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_FAST_TYPE_ID_H_

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// Copyright 2020 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/fast_type_id.h"
#include <cstdint>
#include <map>
#include <vector>
#include "gtest/gtest.h"
namespace {
namespace bi = absl::base_internal;
// NOLINTNEXTLINE
#define PRIM_TYPES(A) \
A(bool) \
A(short) \
A(unsigned short) \
A(int) \
A(unsigned int) \
A(long) \
A(unsigned long) \
A(long long) \
A(unsigned long long) \
A(float) \
A(double) \
A(long double)
TEST(FastTypeIdTest, PrimitiveTypes) {
bi::FastTypeIdType type_ids[] = {
#define A(T) bi::FastTypeId<T>(),
PRIM_TYPES(A)
#undef A
#define A(T) bi::FastTypeId<const T>(),
PRIM_TYPES(A)
#undef A
#define A(T) bi::FastTypeId<volatile T>(),
PRIM_TYPES(A)
#undef A
#define A(T) bi::FastTypeId<const volatile T>(),
PRIM_TYPES(A)
#undef A
};
size_t total_type_ids = sizeof(type_ids) / sizeof(bi::FastTypeIdType);
for (int i = 0; i < total_type_ids; ++i) {
EXPECT_EQ(type_ids[i], type_ids[i]);
for (int j = 0; j < i; ++j) {
EXPECT_NE(type_ids[i], type_ids[j]);
}
}
}
#define FIXED_WIDTH_TYPES(A) \
A(int8_t) \
A(uint8_t) \
A(int16_t) \
A(uint16_t) \
A(int32_t) \
A(uint32_t) \
A(int64_t) \
A(uint64_t)
TEST(FastTypeIdTest, FixedWidthTypes) {
bi::FastTypeIdType type_ids[] = {
#define A(T) bi::FastTypeId<T>(),
FIXED_WIDTH_TYPES(A)
#undef A
#define A(T) bi::FastTypeId<const T>(),
FIXED_WIDTH_TYPES(A)
#undef A
#define A(T) bi::FastTypeId<volatile T>(),
FIXED_WIDTH_TYPES(A)
#undef A
#define A(T) bi::FastTypeId<const volatile T>(),
FIXED_WIDTH_TYPES(A)
#undef A
};
size_t total_type_ids = sizeof(type_ids) / sizeof(bi::FastTypeIdType);
for (int i = 0; i < total_type_ids; ++i) {
EXPECT_EQ(type_ids[i], type_ids[i]);
for (int j = 0; j < i; ++j) {
EXPECT_NE(type_ids[i], type_ids[j]);
}
}
}
TEST(FastTypeIdTest, AliasTypes) {
using int_alias = int;
EXPECT_EQ(bi::FastTypeId<int_alias>(), bi::FastTypeId<int>());
}
TEST(FastTypeIdTest, TemplateSpecializations) {
EXPECT_NE(bi::FastTypeId<std::vector<int>>(),
bi::FastTypeId<std::vector<long>>());
EXPECT_NE((bi::FastTypeId<std::map<int, float>>()),
(bi::FastTypeId<std::map<int, double>>()));
}
struct Base {};
struct Derived : Base {};
struct PDerived : private Base {};
TEST(FastTypeIdTest, Inheritance) {
EXPECT_NE(bi::FastTypeId<Base>(), bi::FastTypeId<Derived>());
EXPECT_NE(bi::FastTypeId<Base>(), bi::FastTypeId<PDerived>());
}
} // namespace

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// 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.
#ifndef ABSL_BASE_INTERNAL_HIDE_PTR_H_
#define ABSL_BASE_INTERNAL_HIDE_PTR_H_
#include <cstdint>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Arbitrary value with high bits set. Xor'ing with it is unlikely
// to map one valid pointer to another valid pointer.
constexpr uintptr_t HideMask() {
return (uintptr_t{0xF03A5F7BU} << (sizeof(uintptr_t) - 4) * 8) | 0xF03A5F7BU;
}
// Hide a pointer from the leak checker. For internal use only.
// Differs from absl::IgnoreLeak(ptr) in that absl::IgnoreLeak(ptr) causes ptr
// and all objects reachable from ptr to be ignored by the leak checker.
template <class T>
inline uintptr_t HidePtr(T* ptr) {
return reinterpret_cast<uintptr_t>(ptr) ^ HideMask();
}
// Return a pointer that has been hidden from the leak checker.
// For internal use only.
template <class T>
inline T* UnhidePtr(uintptr_t hidden) {
return reinterpret_cast<T*>(hidden ^ HideMask());
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_HIDE_PTR_H_

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// 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.
//
#ifndef ABSL_BASE_INTERNAL_IDENTITY_H_
#define ABSL_BASE_INTERNAL_IDENTITY_H_
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace internal {
// This is a back-fill of C++20's `std::type_identity`.
template <typename T>
struct type_identity {
typedef T type;
};
// This is a back-fill of C++20's `std::type_identity_t`.
template <typename T>
using type_identity_t = typename type_identity<T>::type;
} // namespace internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_IDENTITY_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_INLINE_VARIABLE_H_
#define ABSL_BASE_INTERNAL_INLINE_VARIABLE_H_
#include <type_traits>
#include "absl/base/internal/identity.h"
// File:
// This file define a macro that allows the creation of or emulation of C++17
// inline variables based on whether or not the feature is supported.
////////////////////////////////////////////////////////////////////////////////
// Macro: ABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init)
//
// Description:
// Expands to the equivalent of an inline constexpr instance of the specified
// `type` and `name`, initialized to the value `init`. If the compiler being
// used is detected as supporting actual inline variables as a language
// feature, then the macro expands to an actual inline variable definition.
//
// Requires:
// `type` is a type that is usable in an extern variable declaration.
//
// Requires: `name` is a valid identifier
//
// Requires:
// `init` is an expression that can be used in the following definition:
// constexpr type name = init;
//
// Usage:
//
// // Equivalent to: `inline constexpr size_t variant_npos = -1;`
// ABSL_INTERNAL_INLINE_CONSTEXPR(size_t, variant_npos, -1);
//
// Differences in implementation:
// For a direct, language-level inline variable, decltype(name) will be the
// type that was specified along with const qualification, whereas for
// emulated inline variables, decltype(name) may be different (in practice
// it will likely be a reference type).
////////////////////////////////////////////////////////////////////////////////
#ifdef __cpp_inline_variables
// Clang's -Wmissing-variable-declarations option erroneously warned that
// inline constexpr objects need to be pre-declared. This has now been fixed,
// but we will need to support this workaround for people building with older
// versions of clang.
//
// Bug: https://bugs.llvm.org/show_bug.cgi?id=35862
//
// Note:
// type_identity_t is used here so that the const and name are in the
// appropriate place for pointer types, reference types, function pointer
// types, etc..
#if defined(__clang__)
#define ABSL_INTERNAL_EXTERN_DECL(type, name) \
extern const ::absl::internal::type_identity_t<type> name;
#else // Otherwise, just define the macro to do nothing.
#define ABSL_INTERNAL_EXTERN_DECL(type, name)
#endif // defined(__clang__)
// See above comment at top of file for details.
#define ABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init) \
ABSL_INTERNAL_EXTERN_DECL(type, name) \
inline constexpr ::absl::internal::type_identity_t<type> name = init
#else
// See above comment at top of file for details.
//
// Note:
// type_identity_t is used here so that the const and name are in the
// appropriate place for pointer types, reference types, function pointer
// types, etc..
#define ABSL_INTERNAL_INLINE_CONSTEXPR(var_type, name, init) \
template <class /*AbslInternalDummy*/ = void> \
struct AbslInternalInlineVariableHolder##name { \
static constexpr ::absl::internal::type_identity_t<var_type> kInstance = \
init; \
}; \
\
template <class AbslInternalDummy> \
constexpr ::absl::internal::type_identity_t<var_type> \
AbslInternalInlineVariableHolder##name<AbslInternalDummy>::kInstance; \
\
static constexpr const ::absl::internal::type_identity_t<var_type>& \
name = /* NOLINT */ \
AbslInternalInlineVariableHolder##name<>::kInstance; \
static_assert(sizeof(void (*)(decltype(name))) != 0, \
"Silence unused variable warnings.")
#endif // __cpp_inline_variables
#endif // ABSL_BASE_INTERNAL_INLINE_VARIABLE_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_INLINE_VARIABLE_TESTING_H_
#define ABSL_BASE_INTERNAL_INLINE_VARIABLE_TESTING_H_
#include "absl/base/internal/inline_variable.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace inline_variable_testing_internal {
struct Foo {
int value = 5;
};
ABSL_INTERNAL_INLINE_CONSTEXPR(Foo, inline_variable_foo, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(Foo, other_inline_variable_foo, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(int, inline_variable_int, 5);
ABSL_INTERNAL_INLINE_CONSTEXPR(int, other_inline_variable_int, 5);
ABSL_INTERNAL_INLINE_CONSTEXPR(void(*)(), inline_variable_fun_ptr, nullptr);
const Foo& get_foo_a();
const Foo& get_foo_b();
const int& get_int_a();
const int& get_int_b();
} // namespace inline_variable_testing_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_INLINE_VARIABLE_TESTING_H_

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// 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.
//
// absl::base_internal::invoke(f, args...) is an implementation of
// INVOKE(f, args...) from section [func.require] of the C++ standard.
// When compiled as C++17 and later versions, it is implemented as an alias of
// std::invoke.
//
// [func.require]
// Define INVOKE (f, t1, t2, ..., tN) as follows:
// 1. (t1.*f)(t2, ..., tN) when f is a pointer to a member function of a class T
// and t1 is an object of type T or a reference to an object of type T or a
// reference to an object of a type derived from T;
// 2. ((*t1).*f)(t2, ..., tN) when f is a pointer to a member function of a
// class T and t1 is not one of the types described in the previous item;
// 3. t1.*f when N == 1 and f is a pointer to member data of a class T and t1 is
// an object of type T or a reference to an object of type T or a reference
// to an object of a type derived from T;
// 4. (*t1).*f when N == 1 and f is a pointer to member data of a class T and t1
// is not one of the types described in the previous item;
// 5. f(t1, t2, ..., tN) in all other cases.
//
// The implementation is SFINAE-friendly: substitution failure within invoke()
// isn't an error.
#ifndef ABSL_BASE_INTERNAL_INVOKE_H_
#define ABSL_BASE_INTERNAL_INVOKE_H_
#include "absl/base/config.h"
#if ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L
#include <functional>
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
using std::invoke;
using std::invoke_result_t;
using std::is_invocable_r;
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#else // ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L
#include <algorithm>
#include <type_traits>
#include <utility>
#include "absl/meta/type_traits.h"
// The following code is internal implementation detail. See the comment at the
// top of this file for the API documentation.
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// The five classes below each implement one of the clauses from the definition
// of INVOKE. The inner class template Accept<F, Args...> checks whether the
// clause is applicable; static function template Invoke(f, args...) does the
// invocation.
//
// By separating the clause selection logic from invocation we make sure that
// Invoke() does exactly what the standard says.
template <typename Derived>
struct StrippedAccept {
template <typename... Args>
struct Accept : Derived::template AcceptImpl<typename std::remove_cv<
typename std::remove_reference<Args>::type>::type...> {};
};
// (t1.*f)(t2, ..., tN) when f is a pointer to a member function of a class T
// and t1 is an object of type T or a reference to an object of type T or a
// reference to an object of a type derived from T.
struct MemFunAndRef : StrippedAccept<MemFunAndRef> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename MemFunType, typename C, typename Obj, typename... Args>
struct AcceptImpl<MemFunType C::*, Obj, Args...>
: std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
absl::is_function<MemFunType>::value> {
};
template <typename MemFun, typename Obj, typename... Args>
static decltype((std::declval<Obj>().*
std::declval<MemFun>())(std::declval<Args>()...))
Invoke(MemFun&& mem_fun, Obj&& obj, Args&&... args) {
// Ignore bogus GCC warnings on this line.
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101436 for similar example.
#if ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(11, 0)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Warray-bounds"
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
return (std::forward<Obj>(obj).*
std::forward<MemFun>(mem_fun))(std::forward<Args>(args)...);
#if ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(11, 0)
#pragma GCC diagnostic pop
#endif
}
};
// ((*t1).*f)(t2, ..., tN) when f is a pointer to a member function of a
// class T and t1 is not one of the types described in the previous item.
struct MemFunAndPtr : StrippedAccept<MemFunAndPtr> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename MemFunType, typename C, typename Ptr, typename... Args>
struct AcceptImpl<MemFunType C::*, Ptr, Args...>
: std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
absl::is_function<MemFunType>::value> {
};
template <typename MemFun, typename Ptr, typename... Args>
static decltype(((*std::declval<Ptr>()).*
std::declval<MemFun>())(std::declval<Args>()...))
Invoke(MemFun&& mem_fun, Ptr&& ptr, Args&&... args) {
return ((*std::forward<Ptr>(ptr)).*
std::forward<MemFun>(mem_fun))(std::forward<Args>(args)...);
}
};
// t1.*f when N == 1 and f is a pointer to member data of a class T and t1 is
// an object of type T or a reference to an object of type T or a reference
// to an object of a type derived from T.
struct DataMemAndRef : StrippedAccept<DataMemAndRef> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename R, typename C, typename Obj>
struct AcceptImpl<R C::*, Obj>
: std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
!absl::is_function<R>::value> {};
template <typename DataMem, typename Ref>
static decltype(std::declval<Ref>().*std::declval<DataMem>()) Invoke(
DataMem&& data_mem, Ref&& ref) {
return std::forward<Ref>(ref).*std::forward<DataMem>(data_mem);
}
};
// (*t1).*f when N == 1 and f is a pointer to member data of a class T and t1
// is not one of the types described in the previous item.
struct DataMemAndPtr : StrippedAccept<DataMemAndPtr> {
template <typename... Args>
struct AcceptImpl : std::false_type {};
template <typename R, typename C, typename Ptr>
struct AcceptImpl<R C::*, Ptr>
: std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
!absl::is_function<R>::value> {};
template <typename DataMem, typename Ptr>
static decltype((*std::declval<Ptr>()).*std::declval<DataMem>()) Invoke(
DataMem&& data_mem, Ptr&& ptr) {
return (*std::forward<Ptr>(ptr)).*std::forward<DataMem>(data_mem);
}
};
// f(t1, t2, ..., tN) in all other cases.
struct Callable {
// Callable doesn't have Accept because it's the last clause that gets picked
// when none of the previous clauses are applicable.
template <typename F, typename... Args>
static decltype(std::declval<F>()(std::declval<Args>()...)) Invoke(
F&& f, Args&&... args) {
return std::forward<F>(f)(std::forward<Args>(args)...);
}
};
// Resolves to the first matching clause.
template <typename... Args>
struct Invoker {
typedef typename std::conditional<
MemFunAndRef::Accept<Args...>::value, MemFunAndRef,
typename std::conditional<
MemFunAndPtr::Accept<Args...>::value, MemFunAndPtr,
typename std::conditional<
DataMemAndRef::Accept<Args...>::value, DataMemAndRef,
typename std::conditional<DataMemAndPtr::Accept<Args...>::value,
DataMemAndPtr, Callable>::type>::type>::
type>::type type;
};
// The result type of Invoke<F, Args...>.
template <typename F, typename... Args>
using invoke_result_t = decltype(Invoker<F, Args...>::type::Invoke(
std::declval<F>(), std::declval<Args>()...));
// Invoke(f, args...) is an implementation of INVOKE(f, args...) from section
// [func.require] of the C++ standard.
template <typename F, typename... Args>
invoke_result_t<F, Args...> invoke(F&& f, Args&&... args) {
return Invoker<F, Args...>::type::Invoke(std::forward<F>(f),
std::forward<Args>(args)...);
}
template <typename AlwaysVoid, typename, typename, typename...>
struct IsInvocableRImpl : std::false_type {};
template <typename R, typename F, typename... Args>
struct IsInvocableRImpl<
absl::void_t<absl::base_internal::invoke_result_t<F, Args...> >, R, F,
Args...>
: std::integral_constant<
bool,
std::is_convertible<absl::base_internal::invoke_result_t<F, Args...>,
R>::value ||
std::is_void<R>::value> {};
// Type trait whose member `value` is true if invoking `F` with `Args` is valid,
// and either the return type is convertible to `R`, or `R` is void.
// C++11-compatible version of `std::is_invocable_r`.
template <typename R, typename F, typename... Args>
using is_invocable_r = IsInvocableRImpl<void, R, F, Args...>;
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_INTERNAL_CPLUSPLUS_LANG >= 201703L
#endif // ABSL_BASE_INTERNAL_INVOKE_H_

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// 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.
// A low-level allocator that can be used by other low-level
// modules without introducing dependency cycles.
// This allocator is slow and wasteful of memory;
// it should not be used when performance is key.
#include "absl/base/internal/low_level_alloc.h"
#include <type_traits>
#include "absl/base/call_once.h"
#include "absl/base/config.h"
#include "absl/base/internal/direct_mmap.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/macros.h"
#include "absl/base/thread_annotations.h"
// LowLevelAlloc requires that the platform support low-level
// allocation of virtual memory. Platforms lacking this cannot use
// LowLevelAlloc.
#ifndef ABSL_LOW_LEVEL_ALLOC_MISSING
#ifndef _WIN32
#include <pthread.h>
#include <signal.h>
#include <sys/mman.h>
#include <unistd.h>
#else
#include <windows.h>
#endif
#ifdef __linux__
#include <sys/prctl.h>
#endif
#include <string.h>
#include <algorithm>
#include <atomic>
#include <cerrno>
#include <cstddef>
#include <new> // for placement-new
#include "absl/base/dynamic_annotations.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/spinlock.h"
#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// A first-fit allocator with amortized logarithmic free() time.
// ---------------------------------------------------------------------------
static const int kMaxLevel = 30;
namespace {
// This struct describes one allocated block, or one free block.
struct AllocList {
struct Header {
// Size of entire region, including this field. Must be
// first. Valid in both allocated and unallocated blocks.
uintptr_t size;
// kMagicAllocated or kMagicUnallocated xor this.
uintptr_t magic;
// Pointer to parent arena.
LowLevelAlloc::Arena *arena;
// Aligns regions to 0 mod 2*sizeof(void*).
void *dummy_for_alignment;
} header;
// Next two fields: in unallocated blocks: freelist skiplist data
// in allocated blocks: overlaps with client data
// Levels in skiplist used.
int levels;
// Actually has levels elements. The AllocList node may not have room
// for all kMaxLevel entries. See max_fit in LLA_SkiplistLevels().
AllocList *next[kMaxLevel];
};
} // namespace
// ---------------------------------------------------------------------------
// A trivial skiplist implementation. This is used to keep the freelist
// in address order while taking only logarithmic time per insert and delete.
// An integer approximation of log2(size/base)
// Requires size >= base.
static int IntLog2(size_t size, size_t base) {
int result = 0;
for (size_t i = size; i > base; i >>= 1) { // i == floor(size/2**result)
result++;
}
// floor(size / 2**result) <= base < floor(size / 2**(result-1))
// => log2(size/(base+1)) <= result < 1+log2(size/base)
// => result ~= log2(size/base)
return result;
}
// Return a random integer n: p(n)=1/(2**n) if 1 <= n; p(n)=0 if n < 1.
static int Random(uint32_t *state) {
uint32_t r = *state;
int result = 1;
while ((((r = r * 1103515245 + 12345) >> 30) & 1) == 0) {
result++;
}
*state = r;
return result;
}
// Return a number of skiplist levels for a node of size bytes, where
// base is the minimum node size. Compute level=log2(size / base)+n
// where n is 1 if random is false and otherwise a random number generated with
// the standard distribution for a skiplist: See Random() above.
// Bigger nodes tend to have more skiplist levels due to the log2(size / base)
// term, so first-fit searches touch fewer nodes. "level" is clipped so
// level<kMaxLevel and next[level-1] will fit in the node.
// 0 < LLA_SkiplistLevels(x,y,false) <= LLA_SkiplistLevels(x,y,true) < kMaxLevel
static int LLA_SkiplistLevels(size_t size, size_t base, uint32_t *random) {
// max_fit is the maximum number of levels that will fit in a node for the
// given size. We can't return more than max_fit, no matter what the
// random number generator says.
size_t max_fit = (size - offsetof(AllocList, next)) / sizeof(AllocList *);
int level = IntLog2(size, base) + (random != nullptr ? Random(random) : 1);
if (static_cast<size_t>(level) > max_fit) level = static_cast<int>(max_fit);
if (level > kMaxLevel - 1) level = kMaxLevel - 1;
ABSL_RAW_CHECK(level >= 1, "block not big enough for even one level");
return level;
}
// Return "atleast", the first element of AllocList *head s.t. *atleast >= *e.
// For 0 <= i < head->levels, set prev[i] to "no_greater", where no_greater
// points to the last element at level i in the AllocList less than *e, or is
// head if no such element exists.
static AllocList *LLA_SkiplistSearch(AllocList *head, AllocList *e,
AllocList **prev) {
AllocList *p = head;
for (int level = head->levels - 1; level >= 0; level--) {
for (AllocList *n; (n = p->next[level]) != nullptr && n < e; p = n) {
}
prev[level] = p;
}
return (head->levels == 0) ? nullptr : prev[0]->next[0];
}
// Insert element *e into AllocList *head. Set prev[] as LLA_SkiplistSearch.
// Requires that e->levels be previously set by the caller (using
// LLA_SkiplistLevels())
static void LLA_SkiplistInsert(AllocList *head, AllocList *e,
AllocList **prev) {
LLA_SkiplistSearch(head, e, prev);
for (; head->levels < e->levels; head->levels++) { // extend prev pointers
prev[head->levels] = head; // to all *e's levels
}
for (int i = 0; i != e->levels; i++) { // add element to list
e->next[i] = prev[i]->next[i];
prev[i]->next[i] = e;
}
}
// Remove element *e from AllocList *head. Set prev[] as LLA_SkiplistSearch().
// Requires that e->levels be previous set by the caller (using
// LLA_SkiplistLevels())
static void LLA_SkiplistDelete(AllocList *head, AllocList *e,
AllocList **prev) {
AllocList *found = LLA_SkiplistSearch(head, e, prev);
ABSL_RAW_CHECK(e == found, "element not in freelist");
for (int i = 0; i != e->levels && prev[i]->next[i] == e; i++) {
prev[i]->next[i] = e->next[i];
}
while (head->levels > 0 && head->next[head->levels - 1] == nullptr) {
head->levels--; // reduce head->levels if level unused
}
}
// ---------------------------------------------------------------------------
// Arena implementation
// Metadata for an LowLevelAlloc arena instance.
struct LowLevelAlloc::Arena {
// Constructs an arena with the given LowLevelAlloc flags.
explicit Arena(uint32_t flags_value);
base_internal::SpinLock mu;
// Head of free list, sorted by address
AllocList freelist ABSL_GUARDED_BY(mu);
// Count of allocated blocks
int32_t allocation_count ABSL_GUARDED_BY(mu);
// flags passed to NewArena
const uint32_t flags;
// Result of sysconf(_SC_PAGESIZE)
const size_t pagesize;
// Lowest power of two >= max(16, sizeof(AllocList))
const size_t round_up;
// Smallest allocation block size
const size_t min_size;
// PRNG state
uint32_t random ABSL_GUARDED_BY(mu);
};
namespace {
// Static storage space for the lazily-constructed, default global arena
// instances. We require this space because the whole point of LowLevelAlloc
// is to avoid relying on malloc/new.
alignas(LowLevelAlloc::Arena) unsigned char default_arena_storage[sizeof(
LowLevelAlloc::Arena)];
alignas(LowLevelAlloc::Arena) unsigned char unhooked_arena_storage[sizeof(
LowLevelAlloc::Arena)];
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
alignas(
LowLevelAlloc::Arena) unsigned char unhooked_async_sig_safe_arena_storage
[sizeof(LowLevelAlloc::Arena)];
#endif
// We must use LowLevelCallOnce here to construct the global arenas, rather than
// using function-level statics, to avoid recursively invoking the scheduler.
absl::once_flag create_globals_once;
void CreateGlobalArenas() {
new (&default_arena_storage)
LowLevelAlloc::Arena(LowLevelAlloc::kCallMallocHook);
new (&unhooked_arena_storage) LowLevelAlloc::Arena(0);
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
new (&unhooked_async_sig_safe_arena_storage)
LowLevelAlloc::Arena(LowLevelAlloc::kAsyncSignalSafe);
#endif
}
// Returns a global arena that does not call into hooks. Used by NewArena()
// when kCallMallocHook is not set.
LowLevelAlloc::Arena *UnhookedArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
return reinterpret_cast<LowLevelAlloc::Arena *>(&unhooked_arena_storage);
}
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
// Returns a global arena that is async-signal safe. Used by NewArena() when
// kAsyncSignalSafe is set.
LowLevelAlloc::Arena *UnhookedAsyncSigSafeArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
return reinterpret_cast<LowLevelAlloc::Arena *>(
&unhooked_async_sig_safe_arena_storage);
}
#endif
} // namespace
// Returns the default arena, as used by LowLevelAlloc::Alloc() and friends.
LowLevelAlloc::Arena *LowLevelAlloc::DefaultArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
return reinterpret_cast<LowLevelAlloc::Arena *>(&default_arena_storage);
}
// magic numbers to identify allocated and unallocated blocks
static const uintptr_t kMagicAllocated = 0x4c833e95U;
static const uintptr_t kMagicUnallocated = ~kMagicAllocated;
namespace {
class ABSL_SCOPED_LOCKABLE ArenaLock {
public:
explicit ArenaLock(LowLevelAlloc::Arena *arena)
ABSL_EXCLUSIVE_LOCK_FUNCTION(arena->mu)
: arena_(arena) {
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
sigset_t all;
sigfillset(&all);
mask_valid_ = pthread_sigmask(SIG_BLOCK, &all, &mask_) == 0;
}
#endif
arena_->mu.Lock();
}
~ArenaLock() { ABSL_RAW_CHECK(left_, "haven't left Arena region"); }
void Leave() ABSL_UNLOCK_FUNCTION() {
arena_->mu.Unlock();
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (mask_valid_) {
const int err = pthread_sigmask(SIG_SETMASK, &mask_, nullptr);
if (err != 0) {
ABSL_RAW_LOG(FATAL, "pthread_sigmask failed: %d", err);
}
}
#endif
left_ = true;
}
private:
bool left_ = false; // whether left region
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
bool mask_valid_ = false;
sigset_t mask_; // old mask of blocked signals
#endif
LowLevelAlloc::Arena *arena_;
ArenaLock(const ArenaLock &) = delete;
ArenaLock &operator=(const ArenaLock &) = delete;
};
} // namespace
// create an appropriate magic number for an object at "ptr"
// "magic" should be kMagicAllocated or kMagicUnallocated
inline static uintptr_t Magic(uintptr_t magic, AllocList::Header *ptr) {
return magic ^ reinterpret_cast<uintptr_t>(ptr);
}
namespace {
size_t GetPageSize() {
#ifdef _WIN32
SYSTEM_INFO system_info;
GetSystemInfo(&system_info);
return std::max(system_info.dwPageSize, system_info.dwAllocationGranularity);
#elif defined(__wasm__) || defined(__asmjs__) || defined(__hexagon__)
return getpagesize();
#else
return static_cast<size_t>(sysconf(_SC_PAGESIZE));
#endif
}
size_t RoundedUpBlockSize() {
// Round up block sizes to a power of two close to the header size.
size_t round_up = 16;
while (round_up < sizeof(AllocList::Header)) {
round_up += round_up;
}
return round_up;
}
} // namespace
LowLevelAlloc::Arena::Arena(uint32_t flags_value)
: mu(base_internal::SCHEDULE_KERNEL_ONLY),
allocation_count(0),
flags(flags_value),
pagesize(GetPageSize()),
round_up(RoundedUpBlockSize()),
min_size(2 * round_up),
random(0) {
freelist.header.size = 0;
freelist.header.magic = Magic(kMagicUnallocated, &freelist.header);
freelist.header.arena = this;
freelist.levels = 0;
memset(freelist.next, 0, sizeof(freelist.next));
}
// L < meta_data_arena->mu
LowLevelAlloc::Arena *LowLevelAlloc::NewArena(uint32_t flags) {
Arena *meta_data_arena = DefaultArena();
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
meta_data_arena = UnhookedAsyncSigSafeArena();
} else // NOLINT(readability/braces)
#endif
if ((flags & LowLevelAlloc::kCallMallocHook) == 0) {
meta_data_arena = UnhookedArena();
}
Arena *result =
new (AllocWithArena(sizeof(*result), meta_data_arena)) Arena(flags);
return result;
}
// L < arena->mu, L < arena->arena->mu
bool LowLevelAlloc::DeleteArena(Arena *arena) {
ABSL_RAW_CHECK(
arena != nullptr && arena != DefaultArena() && arena != UnhookedArena(),
"may not delete default arena");
ArenaLock section(arena);
if (arena->allocation_count != 0) {
section.Leave();
return false;
}
while (arena->freelist.next[0] != nullptr) {
AllocList *region = arena->freelist.next[0];
size_t size = region->header.size;
arena->freelist.next[0] = region->next[0];
ABSL_RAW_CHECK(
region->header.magic == Magic(kMagicUnallocated, &region->header),
"bad magic number in DeleteArena()");
ABSL_RAW_CHECK(region->header.arena == arena,
"bad arena pointer in DeleteArena()");
ABSL_RAW_CHECK(size % arena->pagesize == 0,
"empty arena has non-page-aligned block size");
ABSL_RAW_CHECK(reinterpret_cast<uintptr_t>(region) % arena->pagesize == 0,
"empty arena has non-page-aligned block");
int munmap_result;
#ifdef _WIN32
munmap_result = VirtualFree(region, 0, MEM_RELEASE);
ABSL_RAW_CHECK(munmap_result != 0,
"LowLevelAlloc::DeleteArena: VitualFree failed");
#else
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) == 0) {
munmap_result = munmap(region, size);
} else {
munmap_result = base_internal::DirectMunmap(region, size);
}
#else
munmap_result = munmap(region, size);
#endif // ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (munmap_result != 0) {
ABSL_RAW_LOG(FATAL, "LowLevelAlloc::DeleteArena: munmap failed: %d",
errno);
}
#endif // _WIN32
}
section.Leave();
arena->~Arena();
Free(arena);
return true;
}
// ---------------------------------------------------------------------------
// Addition, checking for overflow. The intent is to die if an external client
// manages to push through a request that would cause arithmetic to fail.
static inline uintptr_t CheckedAdd(uintptr_t a, uintptr_t b) {
uintptr_t sum = a + b;
ABSL_RAW_CHECK(sum >= a, "LowLevelAlloc arithmetic overflow");
return sum;
}
// Return value rounded up to next multiple of align.
// align must be a power of two.
static inline uintptr_t RoundUp(uintptr_t addr, uintptr_t align) {
return CheckedAdd(addr, align - 1) & ~(align - 1);
}
// Equivalent to "return prev->next[i]" but with sanity checking
// that the freelist is in the correct order, that it
// consists of regions marked "unallocated", and that no two regions
// are adjacent in memory (they should have been coalesced).
// L >= arena->mu
static AllocList *Next(int i, AllocList *prev, LowLevelAlloc::Arena *arena) {
ABSL_RAW_CHECK(i < prev->levels, "too few levels in Next()");
AllocList *next = prev->next[i];
if (next != nullptr) {
ABSL_RAW_CHECK(
next->header.magic == Magic(kMagicUnallocated, &next->header),
"bad magic number in Next()");
ABSL_RAW_CHECK(next->header.arena == arena, "bad arena pointer in Next()");
if (prev != &arena->freelist) {
ABSL_RAW_CHECK(prev < next, "unordered freelist");
ABSL_RAW_CHECK(reinterpret_cast<char *>(prev) + prev->header.size <
reinterpret_cast<char *>(next),
"malformed freelist");
}
}
return next;
}
// Coalesce list item "a" with its successor if they are adjacent.
static void Coalesce(AllocList *a) {
AllocList *n = a->next[0];
if (n != nullptr && reinterpret_cast<char *>(a) + a->header.size ==
reinterpret_cast<char *>(n)) {
LowLevelAlloc::Arena *arena = a->header.arena;
a->header.size += n->header.size;
n->header.magic = 0;
n->header.arena = nullptr;
AllocList *prev[kMaxLevel];
LLA_SkiplistDelete(&arena->freelist, n, prev);
LLA_SkiplistDelete(&arena->freelist, a, prev);
a->levels =
LLA_SkiplistLevels(a->header.size, arena->min_size, &arena->random);
LLA_SkiplistInsert(&arena->freelist, a, prev);
}
}
// Adds block at location "v" to the free list
// L >= arena->mu
static void AddToFreelist(void *v, LowLevelAlloc::Arena *arena) {
AllocList *f = reinterpret_cast<AllocList *>(reinterpret_cast<char *>(v) -
sizeof(f->header));
ABSL_RAW_CHECK(f->header.magic == Magic(kMagicAllocated, &f->header),
"bad magic number in AddToFreelist()");
ABSL_RAW_CHECK(f->header.arena == arena,
"bad arena pointer in AddToFreelist()");
f->levels =
LLA_SkiplistLevels(f->header.size, arena->min_size, &arena->random);
AllocList *prev[kMaxLevel];
LLA_SkiplistInsert(&arena->freelist, f, prev);
f->header.magic = Magic(kMagicUnallocated, &f->header);
Coalesce(f); // maybe coalesce with successor
Coalesce(prev[0]); // maybe coalesce with predecessor
}
// Frees storage allocated by LowLevelAlloc::Alloc().
// L < arena->mu
void LowLevelAlloc::Free(void *v) {
if (v != nullptr) {
AllocList *f = reinterpret_cast<AllocList *>(reinterpret_cast<char *>(v) -
sizeof(f->header));
LowLevelAlloc::Arena *arena = f->header.arena;
ArenaLock section(arena);
AddToFreelist(v, arena);
ABSL_RAW_CHECK(arena->allocation_count > 0, "nothing in arena to free");
arena->allocation_count--;
section.Leave();
}
}
// allocates and returns a block of size bytes, to be freed with Free()
// L < arena->mu
static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
void *result = nullptr;
if (request != 0) {
AllocList *s; // will point to region that satisfies request
ArenaLock section(arena);
// round up with header
size_t req_rnd =
RoundUp(CheckedAdd(request, sizeof(s->header)), arena->round_up);
for (;;) { // loop until we find a suitable region
// find the minimum levels that a block of this size must have
int i = LLA_SkiplistLevels(req_rnd, arena->min_size, nullptr) - 1;
if (i < arena->freelist.levels) { // potential blocks exist
AllocList *before = &arena->freelist; // predecessor of s
while ((s = Next(i, before, arena)) != nullptr &&
s->header.size < req_rnd) {
before = s;
}
if (s != nullptr) { // we found a region
break;
}
}
// we unlock before mmap() both because mmap() may call a callback hook,
// and because it may be slow.
arena->mu.Unlock();
// mmap generous 64K chunks to decrease
// the chances/impact of fragmentation:
size_t new_pages_size = RoundUp(req_rnd, arena->pagesize * 16);
void *new_pages;
#ifdef _WIN32
new_pages = VirtualAlloc(nullptr, new_pages_size,
MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
ABSL_RAW_CHECK(new_pages != nullptr, "VirtualAlloc failed");
#else
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
new_pages = base_internal::DirectMmap(nullptr, new_pages_size,
PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
} else {
new_pages = mmap(nullptr, new_pages_size, PROT_WRITE | PROT_READ,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
}
#else
new_pages = mmap(nullptr, new_pages_size, PROT_WRITE | PROT_READ,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
#endif // ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (new_pages == MAP_FAILED) {
ABSL_RAW_LOG(FATAL, "mmap error: %d", errno);
}
#ifdef __linux__
#if defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME)
// Attempt to name the allocated address range in /proc/$PID/smaps on
// Linux.
//
// This invocation of prctl() may fail if the Linux kernel was not
// configured with the CONFIG_ANON_VMA_NAME option. This is OK since
// the naming of arenas is primarily a debugging aid.
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, new_pages, new_pages_size,
"absl");
#endif
#endif // __linux__
#endif // _WIN32
arena->mu.Lock();
s = reinterpret_cast<AllocList *>(new_pages);
s->header.size = new_pages_size;
// Pretend the block is allocated; call AddToFreelist() to free it.
s->header.magic = Magic(kMagicAllocated, &s->header);
s->header.arena = arena;
AddToFreelist(&s->levels, arena); // insert new region into free list
}
AllocList *prev[kMaxLevel];
LLA_SkiplistDelete(&arena->freelist, s, prev); // remove from free list
// s points to the first free region that's big enough
if (CheckedAdd(req_rnd, arena->min_size) <= s->header.size) {
// big enough to split
AllocList *n =
reinterpret_cast<AllocList *>(req_rnd + reinterpret_cast<char *>(s));
n->header.size = s->header.size - req_rnd;
n->header.magic = Magic(kMagicAllocated, &n->header);
n->header.arena = arena;
s->header.size = req_rnd;
AddToFreelist(&n->levels, arena);
}
s->header.magic = Magic(kMagicAllocated, &s->header);
ABSL_RAW_CHECK(s->header.arena == arena, "");
arena->allocation_count++;
section.Leave();
result = &s->levels;
}
ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(result, request);
return result;
}
void *LowLevelAlloc::Alloc(size_t request) {
void *result = DoAllocWithArena(request, DefaultArena());
return result;
}
void *LowLevelAlloc::AllocWithArena(size_t request, Arena *arena) {
ABSL_RAW_CHECK(arena != nullptr, "must pass a valid arena");
void *result = DoAllocWithArena(request, arena);
return result;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_LOW_LEVEL_ALLOC_MISSING

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// 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.
//
#ifndef ABSL_BASE_INTERNAL_LOW_LEVEL_ALLOC_H_
#define ABSL_BASE_INTERNAL_LOW_LEVEL_ALLOC_H_
// A simple thread-safe memory allocator that does not depend on
// mutexes or thread-specific data. It is intended to be used
// sparingly, and only when malloc() would introduce an unwanted
// dependency, such as inside the heap-checker, or the Mutex
// implementation.
// IWYU pragma: private, include "base/low_level_alloc.h"
#include <sys/types.h>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
// LowLevelAlloc requires that the platform support low-level
// allocation of virtual memory. Platforms lacking this cannot use
// LowLevelAlloc.
#ifdef ABSL_LOW_LEVEL_ALLOC_MISSING
#error ABSL_LOW_LEVEL_ALLOC_MISSING cannot be directly set
#elif !defined(ABSL_HAVE_MMAP) && !defined(_WIN32)
#define ABSL_LOW_LEVEL_ALLOC_MISSING 1
#endif
// Using LowLevelAlloc with kAsyncSignalSafe isn't supported on Windows or
// asm.js / WebAssembly.
// See https://kripken.github.io/emscripten-site/docs/porting/pthreads.html
// for more information.
#ifdef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
#error ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING cannot be directly set
#elif defined(_WIN32) || defined(__asmjs__) || defined(__wasm__) || \
defined(__hexagon__)
#define ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING 1
#endif
#include <cstddef>
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
class LowLevelAlloc {
public:
struct Arena; // an arena from which memory may be allocated
// Returns a pointer to a block of at least "request" bytes
// that have been newly allocated from the specific arena.
// for Alloc() call the DefaultArena() is used.
// Returns 0 if passed request==0.
// Does not return 0 under other circumstances; it crashes if memory
// is not available.
static void *Alloc(size_t request) ABSL_ATTRIBUTE_SECTION(malloc_hook);
static void *AllocWithArena(size_t request, Arena *arena)
ABSL_ATTRIBUTE_SECTION(malloc_hook);
// Deallocates a region of memory that was previously allocated with
// Alloc(). Does nothing if passed 0. "s" must be either 0,
// or must have been returned from a call to Alloc() and not yet passed to
// Free() since that call to Alloc(). The space is returned to the arena
// from which it was allocated.
static void Free(void *s) ABSL_ATTRIBUTE_SECTION(malloc_hook);
// ABSL_ATTRIBUTE_SECTION(malloc_hook) for Alloc* and Free
// are to put all callers of MallocHook::Invoke* in this module
// into special section,
// so that MallocHook::GetCallerStackTrace can function accurately.
// Create a new arena.
// The root metadata for the new arena is allocated in the
// meta_data_arena; the DefaultArena() can be passed for meta_data_arena.
// These values may be ored into flags:
enum {
// Report calls to Alloc() and Free() via the MallocHook interface.
// Set in the DefaultArena.
kCallMallocHook = 0x0001,
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
// Make calls to Alloc(), Free() be async-signal-safe. Not set in
// DefaultArena(). Not supported on all platforms.
kAsyncSignalSafe = 0x0002,
#endif
};
// Construct a new arena. The allocation of the underlying metadata honors
// the provided flags. For example, the call NewArena(kAsyncSignalSafe)
// is itself async-signal-safe, as well as generatating an arena that provides
// async-signal-safe Alloc/Free.
static Arena *NewArena(uint32_t flags);
// Destroys an arena allocated by NewArena and returns true,
// provided no allocated blocks remain in the arena.
// If allocated blocks remain in the arena, does nothing and
// returns false.
// It is illegal to attempt to destroy the DefaultArena().
static bool DeleteArena(Arena *arena);
// The default arena that always exists.
static Arena *DefaultArena();
private:
LowLevelAlloc(); // no instances
};
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_LOW_LEVEL_ALLOC_H_

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// 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/low_level_alloc.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <thread> // NOLINT(build/c++11)
#include <unordered_map>
#include <utility>
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
#endif
#include "absl/container/node_hash_map.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
// This test doesn't use gtest since it needs to test that everything
// works before main().
#define TEST_ASSERT(x) \
if (!(x)) { \
printf("TEST_ASSERT(%s) FAILED ON LINE %d\n", #x, __LINE__); \
abort(); \
}
// a block of memory obtained from the allocator
struct BlockDesc {
char *ptr; // pointer to memory
int len; // number of bytes
int fill; // filled with data starting with this
};
// Check that the pattern placed in the block d
// by RandomizeBlockDesc is still there.
static void CheckBlockDesc(const BlockDesc &d) {
for (int i = 0; i != d.len; i++) {
TEST_ASSERT((d.ptr[i] & 0xff) == ((d.fill + i) & 0xff));
}
}
// Fill the block "*d" with a pattern
// starting with a random byte.
static void RandomizeBlockDesc(BlockDesc *d) {
d->fill = rand() & 0xff;
for (int i = 0; i != d->len; i++) {
d->ptr[i] = (d->fill + i) & 0xff;
}
}
// Use to indicate to the malloc hooks that
// this calls is from LowLevelAlloc.
static bool using_low_level_alloc = false;
// n times, toss a coin, and based on the outcome
// either allocate a new block or deallocate an old block.
// New blocks are placed in a std::unordered_map with a random key
// and initialized with RandomizeBlockDesc().
// If keys conflict, the older block is freed.
// Old blocks are always checked with CheckBlockDesc()
// before being freed. At the end of the run,
// all remaining allocated blocks are freed.
// If use_new_arena is true, use a fresh arena, and then delete it.
// If call_malloc_hook is true and user_arena is true,
// allocations and deallocations are reported via the MallocHook
// interface.
static void Test(bool use_new_arena, bool call_malloc_hook, int n) {
typedef absl::node_hash_map<int, BlockDesc> AllocMap;
AllocMap allocated;
AllocMap::iterator it;
BlockDesc block_desc;
int rnd;
LowLevelAlloc::Arena *arena = nullptr;
if (use_new_arena) {
int32_t flags = call_malloc_hook ? LowLevelAlloc::kCallMallocHook : 0;
arena = LowLevelAlloc::NewArena(flags);
}
for (int i = 0; i != n; i++) {
if (i != 0 && i % 10000 == 0) {
printf(".");
fflush(stdout);
}
switch (rand() & 1) { // toss a coin
case 0: // coin came up heads: add a block
using_low_level_alloc = true;
block_desc.len = rand() & 0x3fff;
block_desc.ptr = reinterpret_cast<char *>(
arena == nullptr
? LowLevelAlloc::Alloc(block_desc.len)
: LowLevelAlloc::AllocWithArena(block_desc.len, arena));
using_low_level_alloc = false;
RandomizeBlockDesc(&block_desc);
rnd = rand();
it = allocated.find(rnd);
if (it != allocated.end()) {
CheckBlockDesc(it->second);
using_low_level_alloc = true;
LowLevelAlloc::Free(it->second.ptr);
using_low_level_alloc = false;
it->second = block_desc;
} else {
allocated[rnd] = block_desc;
}
break;
case 1: // coin came up tails: remove a block
it = allocated.begin();
if (it != allocated.end()) {
CheckBlockDesc(it->second);
using_low_level_alloc = true;
LowLevelAlloc::Free(it->second.ptr);
using_low_level_alloc = false;
allocated.erase(it);
}
break;
}
}
// remove all remaining blocks
while ((it = allocated.begin()) != allocated.end()) {
CheckBlockDesc(it->second);
using_low_level_alloc = true;
LowLevelAlloc::Free(it->second.ptr);
using_low_level_alloc = false;
allocated.erase(it);
}
if (use_new_arena) {
TEST_ASSERT(LowLevelAlloc::DeleteArena(arena));
}
}
// LowLevelAlloc is designed to be safe to call before main().
static struct BeforeMain {
BeforeMain() {
Test(false, false, 50000);
Test(true, false, 50000);
Test(true, true, 50000);
}
} before_main;
} // namespace
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
int main(int argc, char *argv[]) {
// The actual test runs in the global constructor of `before_main`.
printf("PASS\n");
#ifdef __EMSCRIPTEN__
// clang-format off
// This is JS here. Don't try to format it.
MAIN_THREAD_EM_ASM({
if (ENVIRONMENT_IS_WEB) {
if (typeof TEST_FINISH === 'function') {
TEST_FINISH($0);
} else {
console.error('Attempted to exit with status ' + $0);
console.error('But TEST_FINSIHED is not a function.');
}
}
}, 0);
// clang-format on
#endif
return 0;
}

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// 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.
//
// Core interfaces and definitions used by by low-level interfaces such as
// SpinLock.
#ifndef ABSL_BASE_INTERNAL_LOW_LEVEL_SCHEDULING_H_
#define ABSL_BASE_INTERNAL_LOW_LEVEL_SCHEDULING_H_
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/macros.h"
// The following two declarations exist so SchedulingGuard may friend them with
// the appropriate language linkage. These callbacks allow libc internals, such
// as function level statics, to schedule cooperatively when locking.
extern "C" bool __google_disable_rescheduling(void);
extern "C" void __google_enable_rescheduling(bool disable_result);
namespace absl {
ABSL_NAMESPACE_BEGIN
class CondVar;
class Mutex;
namespace synchronization_internal {
int MutexDelay(int32_t c, int mode);
} // namespace synchronization_internal
namespace base_internal {
class SchedulingHelper; // To allow use of SchedulingGuard.
class SpinLock; // To allow use of SchedulingGuard.
// SchedulingGuard
// Provides guard semantics that may be used to disable cooperative rescheduling
// of the calling thread within specific program blocks. This is used to
// protect resources (e.g. low-level SpinLocks or Domain code) that cooperative
// scheduling depends on.
//
// Domain implementations capable of rescheduling in reaction to involuntary
// kernel thread actions (e.g blocking due to a pagefault or syscall) must
// guarantee that an annotated thread is not allowed to (cooperatively)
// reschedule until the annotated region is complete.
//
// It is an error to attempt to use a cooperatively scheduled resource (e.g.
// Mutex) within a rescheduling-disabled region.
//
// All methods are async-signal safe.
class SchedulingGuard {
public:
// Returns true iff the calling thread may be cooperatively rescheduled.
static bool ReschedulingIsAllowed();
SchedulingGuard(const SchedulingGuard&) = delete;
SchedulingGuard& operator=(const SchedulingGuard&) = delete;
private:
// Disable cooperative rescheduling of the calling thread. It may still
// initiate scheduling operations (e.g. wake-ups), however, it may not itself
// reschedule. Nestable. The returned result is opaque, clients should not
// attempt to interpret it.
// REQUIRES: Result must be passed to a pairing EnableScheduling().
static bool DisableRescheduling();
// Marks the end of a rescheduling disabled region, previously started by
// DisableRescheduling().
// REQUIRES: Pairs with innermost call (and result) of DisableRescheduling().
static void EnableRescheduling(bool disable_result);
// A scoped helper for {Disable, Enable}Rescheduling().
// REQUIRES: destructor must run in same thread as constructor.
struct ScopedDisable {
ScopedDisable() { disabled = SchedulingGuard::DisableRescheduling(); }
~ScopedDisable() { SchedulingGuard::EnableRescheduling(disabled); }
bool disabled;
};
// A scoped helper to enable rescheduling temporarily.
// REQUIRES: destructor must run in same thread as constructor.
class ScopedEnable {
public:
ScopedEnable();
~ScopedEnable();
private:
int scheduling_disabled_depth_;
};
// Access to SchedulingGuard is explicitly permitted.
friend class absl::CondVar;
friend class absl::Mutex;
friend class SchedulingHelper;
friend class SpinLock;
friend int absl::synchronization_internal::MutexDelay(int32_t c, int mode);
};
//------------------------------------------------------------------------------
// End of public interfaces.
//------------------------------------------------------------------------------
inline bool SchedulingGuard::ReschedulingIsAllowed() {
return false;
}
inline bool SchedulingGuard::DisableRescheduling() {
return false;
}
inline void SchedulingGuard::EnableRescheduling(bool /* disable_result */) {
return;
}
inline SchedulingGuard::ScopedEnable::ScopedEnable()
: scheduling_disabled_depth_(0) {}
inline SchedulingGuard::ScopedEnable::~ScopedEnable() {
ABSL_RAW_CHECK(scheduling_disabled_depth_ == 0, "disable unused warning");
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_LOW_LEVEL_SCHEDULING_H_

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// Copyright 2023 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_NULLABILITY_IMPL_H_
#define ABSL_BASE_INTERNAL_NULLABILITY_IMPL_H_
#include <memory>
#include <type_traits>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/meta/type_traits.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace nullability_internal {
template <typename T>
using NullableImpl
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::annotate)
[[clang::annotate("Nullable")]]
#endif
// Don't add the _Nullable attribute in Objective-C compiles. Many Objective-C
// projects enable the `-Wnullable-to-nonnull-conversion warning`, which is
// liable to produce false positives.
#if ABSL_HAVE_FEATURE(nullability_on_classes) && !defined(__OBJC__)
= T _Nullable;
#else
= T;
#endif
template <typename T>
using NonnullImpl
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::annotate)
[[clang::annotate("Nonnull")]]
#endif
#if ABSL_HAVE_FEATURE(nullability_on_classes) && !defined(__OBJC__)
= T _Nonnull;
#else
= T;
#endif
template <typename T>
using NullabilityUnknownImpl
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::annotate)
[[clang::annotate("Nullability_Unspecified")]]
#endif
#if ABSL_HAVE_FEATURE(nullability_on_classes) && !defined(__OBJC__)
= T _Null_unspecified;
#else
= T;
#endif
} // namespace nullability_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_NULLABILITY_IMPL_H_

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// 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.
#ifndef ABSL_BASE_INTERNAL_PER_THREAD_TLS_H_
#define ABSL_BASE_INTERNAL_PER_THREAD_TLS_H_
// This header defines two macros:
//
// If the platform supports thread-local storage:
//
// * ABSL_PER_THREAD_TLS_KEYWORD is the C keyword needed to declare a
// thread-local variable
// * ABSL_PER_THREAD_TLS is 1
//
// Otherwise:
//
// * ABSL_PER_THREAD_TLS_KEYWORD is empty
// * ABSL_PER_THREAD_TLS is 0
//
// Microsoft C supports thread-local storage.
// GCC supports it if the appropriate version of glibc is available,
// which the programmer can indicate by defining ABSL_HAVE_TLS
#include "absl/base/port.h" // For ABSL_HAVE_TLS
#if defined(ABSL_PER_THREAD_TLS)
#error ABSL_PER_THREAD_TLS cannot be directly set
#elif defined(ABSL_PER_THREAD_TLS_KEYWORD)
#error ABSL_PER_THREAD_TLS_KEYWORD cannot be directly set
#elif defined(ABSL_HAVE_TLS)
#define ABSL_PER_THREAD_TLS_KEYWORD __thread
#define ABSL_PER_THREAD_TLS 1
#elif defined(_MSC_VER)
#define ABSL_PER_THREAD_TLS_KEYWORD __declspec(thread)
#define ABSL_PER_THREAD_TLS 1
#else
#define ABSL_PER_THREAD_TLS_KEYWORD
#define ABSL_PER_THREAD_TLS 0
#endif
#endif // ABSL_BASE_INTERNAL_PER_THREAD_TLS_H_

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// Copyright 2024 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/poison.h"
#include <cstdlib>
#include "absl/base/config.h"
#include "absl/base/internal/direct_mmap.h"
#ifndef _WIN32
#include <unistd.h>
#endif
#if defined(ABSL_HAVE_ADDRESS_SANITIZER)
#include <sanitizer/asan_interface.h>
#elif defined(ABSL_HAVE_MEMORY_SANITIZER)
#include <sanitizer/msan_interface.h>
#elif defined(ABSL_HAVE_MMAP)
#include <sys/mman.h>
#endif
#if defined(_WIN32)
#include <windows.h>
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
size_t GetPageSize() {
#ifdef _WIN32
SYSTEM_INFO system_info;
GetSystemInfo(&system_info);
return system_info.dwPageSize;
#elif defined(__wasm__) || defined(__asmjs__) || defined(__hexagon__)
return getpagesize();
#else
return static_cast<size_t>(sysconf(_SC_PAGESIZE));
#endif
}
} // namespace
void* InitializePoisonedPointerInternal() {
const size_t block_size = GetPageSize();
#if defined(ABSL_HAVE_ADDRESS_SANITIZER)
void* data = malloc(block_size);
ASAN_POISON_MEMORY_REGION(data, block_size);
#elif defined(ABSL_HAVE_MEMORY_SANITIZER)
void* data = malloc(block_size);
__msan_poison(data, block_size);
#elif defined(ABSL_HAVE_MMAP)
void* data = DirectMmap(nullptr, block_size, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (data == MAP_FAILED) return GetBadPointerInternal();
#elif defined(_WIN32)
void* data = VirtualAlloc(nullptr, block_size, MEM_RESERVE | MEM_COMMIT,
PAGE_NOACCESS);
if (data == nullptr) return GetBadPointerInternal();
#else
return GetBadPointerInternal();
#endif
// Return the middle of the block so that dereferences before and after the
// pointer will both crash.
return static_cast<char*>(data) + block_size / 2;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// Copyright 2024 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_POISON_H_
#define ABSL_BASE_INTERNAL_POISON_H_
#include <cstdint>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
inline void* GetBadPointerInternal() {
// A likely bad pointer. Pointers are required to have high bits that are all
// zero or all one for certain 64-bit CPUs. This pointer value will hopefully
// cause a crash on dereference and also be clearly recognizable as invalid.
constexpr uint64_t kBadPtr = 0xBAD0BAD0BAD0BAD0;
auto ret = reinterpret_cast<void*>(static_cast<uintptr_t>(kBadPtr));
#ifndef _MSC_VER // MSVC doesn't support inline asm with `volatile`.
// Try to prevent the compiler from optimizing out the undefined behavior.
asm volatile("" : : "r"(ret) :); // NOLINT
#endif
return ret;
}
void* InitializePoisonedPointerInternal();
inline void* get_poisoned_pointer() {
#if defined(NDEBUG) && !defined(ABSL_HAVE_ADDRESS_SANITIZER) && \
!defined(ABSL_HAVE_MEMORY_SANITIZER)
// In optimized non-sanitized builds, avoid the function-local static because
// of the codegen and runtime cost.
return GetBadPointerInternal();
#else
// Non-optimized builds may use more robust implementation. Note that we can't
// use a static global because Chromium doesn't allow non-constinit globals.
static void* ptr = InitializePoisonedPointerInternal();
return ptr;
#endif
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_POISON_H_

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// Copyright 2024 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/poison.h"
#include <iostream>
#include "gtest/gtest.h"
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
TEST(PoisonTest, CrashesOnDereference) {
#ifdef __ANDROID__
GTEST_SKIP() << "On Android, poisoned pointer dereference times out instead "
"of crashing.";
#endif
int* poisoned_ptr = static_cast<int*>(get_poisoned_pointer());
EXPECT_DEATH_IF_SUPPORTED(std::cout << *poisoned_ptr, "");
EXPECT_DEATH_IF_SUPPORTED(std::cout << *(poisoned_ptr - 10), "");
EXPECT_DEATH_IF_SUPPORTED(std::cout << *(poisoned_ptr + 10), "");
}
} // namespace
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
#ifndef ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_
#define ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_
// ABSL_PRETTY_FUNCTION
//
// In C++11, __func__ gives the undecorated name of the current function. That
// is, "main", not "int main()". Various compilers give extra macros to get the
// decorated function name, including return type and arguments, to
// differentiate between overload sets. ABSL_PRETTY_FUNCTION is a portable
// version of these macros which forwards to the correct macro on each compiler.
#if defined(_MSC_VER)
#define ABSL_PRETTY_FUNCTION __FUNCSIG__
#elif defined(__GNUC__)
#define ABSL_PRETTY_FUNCTION __PRETTY_FUNCTION__
#else
#error "Unsupported compiler"
#endif
#endif // ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_

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// 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/raw_logging.h"
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#ifdef __EMSCRIPTEN__
#include <emscripten/console.h>
#endif
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/atomic_hook.h"
#include "absl/base/internal/errno_saver.h"
#include "absl/base/log_severity.h"
// We know how to perform low-level writes to stderr in POSIX and Windows. For
// these platforms, we define the token ABSL_LOW_LEVEL_WRITE_SUPPORTED.
// Much of raw_logging.cc becomes a no-op when we can't output messages,
// although a FATAL ABSL_RAW_LOG message will still abort the process.
// ABSL_HAVE_POSIX_WRITE is defined when the platform provides posix write()
// (as from unistd.h)
//
// This preprocessor token is also defined in raw_io.cc. If you need to copy
// this, consider moving both to config.h instead.
#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \
defined(__hexagon__) || defined(__Fuchsia__) || \
defined(__native_client__) || defined(__OpenBSD__) || \
defined(__EMSCRIPTEN__) || defined(__ASYLO__)
#include <unistd.h>
#define ABSL_HAVE_POSIX_WRITE 1
#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1
#else
#undef ABSL_HAVE_POSIX_WRITE
#endif
// ABSL_HAVE_SYSCALL_WRITE is defined when the platform provides the syscall
// syscall(SYS_write, /*int*/ fd, /*char* */ buf, /*size_t*/ len);
// for low level operations that want to avoid libc.
#if (defined(__linux__) || defined(__FreeBSD__)) && !defined(__ANDROID__)
#include <sys/syscall.h>
#define ABSL_HAVE_SYSCALL_WRITE 1
#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1
#else
#undef ABSL_HAVE_SYSCALL_WRITE
#endif
#ifdef _WIN32
#include <io.h>
#define ABSL_HAVE_RAW_IO 1
#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1
#else
#undef ABSL_HAVE_RAW_IO
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace raw_log_internal {
namespace {
// TODO(gfalcon): We want raw-logging to work on as many platforms as possible.
// Explicitly `#error` out when not `ABSL_LOW_LEVEL_WRITE_SUPPORTED`, except for
// a selected set of platforms for which we expect not to be able to raw log.
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
constexpr char kTruncated[] = " ... (message truncated)\n";
// sprintf the format to the buffer, adjusting *buf and *size to reflect the
// consumed bytes, and return whether the message fit without truncation. If
// truncation occurred, if possible leave room in the buffer for the message
// kTruncated[].
bool VADoRawLog(char** buf, int* size, const char* format, va_list ap)
ABSL_PRINTF_ATTRIBUTE(3, 0);
bool VADoRawLog(char** buf, int* size, const char* format, va_list ap) {
if (*size < 0) return false;
int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
bool result = true;
if (n < 0 || n > *size) {
result = false;
if (static_cast<size_t>(*size) > sizeof(kTruncated)) {
n = *size - static_cast<int>(sizeof(kTruncated));
} else {
n = 0; // no room for truncation message
}
}
*size -= n;
*buf += n;
return result;
}
#endif // ABSL_LOW_LEVEL_WRITE_SUPPORTED
constexpr int kLogBufSize = 3000;
// CAVEAT: vsnprintf called from *DoRawLog below has some (exotic) code paths
// that invoke malloc() and getenv() that might acquire some locks.
// Helper for RawLog below.
// *DoRawLog writes to *buf of *size and move them past the written portion.
// It returns true iff there was no overflow or error.
bool DoRawLog(char** buf, int* size, const char* format, ...)
ABSL_PRINTF_ATTRIBUTE(3, 4);
bool DoRawLog(char** buf, int* size, const char* format, ...) {
if (*size < 0) return false;
va_list ap;
va_start(ap, format);
int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
va_end(ap);
if (n < 0 || n > *size) return false;
*size -= n;
*buf += n;
return true;
}
bool DefaultLogFilterAndPrefix(absl::LogSeverity, const char* file, int line,
char** buf, int* buf_size) {
DoRawLog(buf, buf_size, "[%s : %d] RAW: ", file, line);
return true;
}
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
absl::base_internal::AtomicHook<LogFilterAndPrefixHook>
log_filter_and_prefix_hook(DefaultLogFilterAndPrefix);
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
absl::base_internal::AtomicHook<AbortHook> abort_hook;
void RawLogVA(absl::LogSeverity severity, const char* file, int line,
const char* format, va_list ap) ABSL_PRINTF_ATTRIBUTE(4, 0);
void RawLogVA(absl::LogSeverity severity, const char* file, int line,
const char* format, va_list ap) {
char buffer[kLogBufSize];
char* buf = buffer;
int size = sizeof(buffer);
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
bool enabled = true;
#else
bool enabled = false;
#endif
#ifdef ABSL_MIN_LOG_LEVEL
if (severity < static_cast<absl::LogSeverity>(ABSL_MIN_LOG_LEVEL) &&
severity < absl::LogSeverity::kFatal) {
enabled = false;
}
#endif
enabled = log_filter_and_prefix_hook(severity, file, line, &buf, &size);
const char* const prefix_end = buf;
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
if (enabled) {
bool no_chop = VADoRawLog(&buf, &size, format, ap);
if (no_chop) {
DoRawLog(&buf, &size, "\n");
} else {
DoRawLog(&buf, &size, "%s", kTruncated);
}
AsyncSignalSafeWriteError(buffer, static_cast<size_t>(buf - buffer));
}
#else
static_cast<void>(format);
static_cast<void>(ap);
static_cast<void>(enabled);
#endif
// Abort the process after logging a FATAL message, even if the output itself
// was suppressed.
if (severity == absl::LogSeverity::kFatal) {
abort_hook(file, line, buffer, prefix_end, buffer + kLogBufSize);
abort();
}
}
// Non-formatting version of RawLog().
//
// TODO(gfalcon): When string_view no longer depends on base, change this
// interface to take its message as a string_view instead.
void DefaultInternalLog(absl::LogSeverity severity, const char* file, int line,
const std::string& message) {
RawLog(severity, file, line, "%.*s", static_cast<int>(message.size()),
message.data());
}
} // namespace
void AsyncSignalSafeWriteError(const char* s, size_t len) {
if (!len) return;
absl::base_internal::ErrnoSaver errno_saver;
#if defined(__EMSCRIPTEN__)
// In WebAssembly, bypass filesystem emulation via fwrite.
if (s[len - 1] == '\n') {
// Skip a trailing newline character as emscripten_errn adds one itself.
len--;
}
// emscripten_errn was introduced in 3.1.41 but broken in standalone mode
// until 3.1.43.
#if ABSL_INTERNAL_EMSCRIPTEN_VERSION >= 3001043
emscripten_errn(s, len);
#else
char buf[kLogBufSize];
if (len >= kLogBufSize) {
len = kLogBufSize - 1;
constexpr size_t trunc_len = sizeof(kTruncated) - 2;
memcpy(buf + len - trunc_len, kTruncated, trunc_len);
buf[len] = '\0';
len -= trunc_len;
} else {
buf[len] = '\0';
}
memcpy(buf, s, len);
_emscripten_err(buf);
#endif
#elif defined(ABSL_HAVE_SYSCALL_WRITE)
// We prefer calling write via `syscall` to minimize the risk of libc doing
// something "helpful".
syscall(SYS_write, STDERR_FILENO, s, len);
#elif defined(ABSL_HAVE_POSIX_WRITE)
write(STDERR_FILENO, s, len);
#elif defined(ABSL_HAVE_RAW_IO)
_write(/* stderr */ 2, s, static_cast<unsigned>(len));
#else
// stderr logging unsupported on this platform
(void)s;
(void)len;
#endif
}
void RawLog(absl::LogSeverity severity, const char* file, int line,
const char* format, ...) {
va_list ap;
va_start(ap, format);
RawLogVA(severity, file, line, format, ap);
va_end(ap);
}
bool RawLoggingFullySupported() {
#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED
return true;
#else // !ABSL_LOW_LEVEL_WRITE_SUPPORTED
return false;
#endif // !ABSL_LOW_LEVEL_WRITE_SUPPORTED
}
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES ABSL_DLL
absl::base_internal::AtomicHook<InternalLogFunction>
internal_log_function(DefaultInternalLog);
void RegisterLogFilterAndPrefixHook(LogFilterAndPrefixHook func) {
log_filter_and_prefix_hook.Store(func);
}
void RegisterAbortHook(AbortHook func) { abort_hook.Store(func); }
void RegisterInternalLogFunction(InternalLogFunction func) {
internal_log_function.Store(func);
}
} // namespace raw_log_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
//
// Thread-safe logging routines that do not allocate any memory or
// acquire any locks, and can therefore be used by low-level memory
// allocation, synchronization, and signal-handling code.
#ifndef ABSL_BASE_INTERNAL_RAW_LOGGING_H_
#define ABSL_BASE_INTERNAL_RAW_LOGGING_H_
#include <string>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/atomic_hook.h"
#include "absl/base/log_severity.h"
#include "absl/base/macros.h"
#include "absl/base/optimization.h"
#include "absl/base/port.h"
// This is similar to LOG(severity) << format..., but
// * it is to be used ONLY by low-level modules that can't use normal LOG()
// * it is designed to be a low-level logger that does not allocate any
// memory and does not need any locks, hence:
// * it logs straight and ONLY to STDERR w/o buffering
// * it uses an explicit printf-format and arguments list
// * it will silently chop off really long message strings
// Usage example:
// ABSL_RAW_LOG(ERROR, "Failed foo with %i: %s", status, error);
// This will print an almost standard log line like this to stderr only:
// E0821 211317 file.cc:123] RAW: Failed foo with 22: bad_file
#define ABSL_RAW_LOG(severity, ...) \
do { \
constexpr const char* absl_raw_log_internal_basename = \
::absl::raw_log_internal::Basename(__FILE__, sizeof(__FILE__) - 1); \
::absl::raw_log_internal::RawLog(ABSL_RAW_LOG_INTERNAL_##severity, \
absl_raw_log_internal_basename, __LINE__, \
__VA_ARGS__); \
ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_##severity; \
} while (0)
// Similar to CHECK(condition) << message, but for low-level modules:
// we use only ABSL_RAW_LOG that does not allocate memory.
// We do not want to provide args list here to encourage this usage:
// if (!cond) ABSL_RAW_LOG(FATAL, "foo ...", hard_to_compute_args);
// so that the args are not computed when not needed.
#define ABSL_RAW_CHECK(condition, message) \
do { \
if (ABSL_PREDICT_FALSE(!(condition))) { \
ABSL_RAW_LOG(FATAL, "Check %s failed: %s", #condition, message); \
} \
} while (0)
// ABSL_INTERNAL_LOG and ABSL_INTERNAL_CHECK work like the RAW variants above,
// except that if the richer log library is linked into the binary, we dispatch
// to that instead. This is potentially useful for internal logging and
// assertions, where we are using RAW_LOG neither for its async-signal-safety
// nor for its non-allocating nature, but rather because raw logging has very
// few other dependencies.
//
// The API is a subset of the above: each macro only takes two arguments. Use
// StrCat if you need to build a richer message.
#define ABSL_INTERNAL_LOG(severity, message) \
do { \
constexpr const char* absl_raw_log_internal_filename = __FILE__; \
::absl::raw_log_internal::internal_log_function( \
ABSL_RAW_LOG_INTERNAL_##severity, absl_raw_log_internal_filename, \
__LINE__, message); \
ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_##severity; \
} while (0)
#define ABSL_INTERNAL_CHECK(condition, message) \
do { \
if (ABSL_PREDICT_FALSE(!(condition))) { \
std::string death_message = "Check " #condition " failed: "; \
death_message += std::string(message); \
ABSL_INTERNAL_LOG(FATAL, death_message); \
} \
} while (0)
#ifndef NDEBUG
#define ABSL_RAW_DLOG(severity, ...) ABSL_RAW_LOG(severity, __VA_ARGS__)
#define ABSL_RAW_DCHECK(condition, message) ABSL_RAW_CHECK(condition, message)
#else // NDEBUG
#define ABSL_RAW_DLOG(severity, ...) \
while (false) ABSL_RAW_LOG(severity, __VA_ARGS__)
#define ABSL_RAW_DCHECK(condition, message) \
while (false) ABSL_RAW_CHECK(condition, message)
#endif // NDEBUG
#define ABSL_RAW_LOG_INTERNAL_INFO ::absl::LogSeverity::kInfo
#define ABSL_RAW_LOG_INTERNAL_WARNING ::absl::LogSeverity::kWarning
#define ABSL_RAW_LOG_INTERNAL_ERROR ::absl::LogSeverity::kError
#define ABSL_RAW_LOG_INTERNAL_FATAL ::absl::LogSeverity::kFatal
#define ABSL_RAW_LOG_INTERNAL_DFATAL ::absl::kLogDebugFatal
#define ABSL_RAW_LOG_INTERNAL_LEVEL(severity) \
::absl::NormalizeLogSeverity(severity)
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_INFO
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_WARNING
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_ERROR
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_FATAL ABSL_UNREACHABLE()
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_DFATAL
#define ABSL_RAW_LOG_INTERNAL_MAYBE_UNREACHABLE_LEVEL(severity)
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace raw_log_internal {
// Helper function to implement ABSL_RAW_LOG
// Logs format... at "severity" level, reporting it
// as called from file:line.
// This does not allocate memory or acquire locks.
void RawLog(absl::LogSeverity severity, const char* file, int line,
const char* format, ...) ABSL_PRINTF_ATTRIBUTE(4, 5);
// Writes the provided buffer directly to stderr, in a signal-safe, low-level
// manner. Preserves errno.
void AsyncSignalSafeWriteError(const char* s, size_t len);
// compile-time function to get the "base" filename, that is, the part of
// a filename after the last "/" or "\" path separator. The search starts at
// the end of the string; the second parameter is the length of the string.
constexpr const char* Basename(const char* fname, int offset) {
return offset == 0 || fname[offset - 1] == '/' || fname[offset - 1] == '\\'
? fname + offset
: Basename(fname, offset - 1);
}
// For testing only.
// Returns true if raw logging is fully supported. When it is not
// fully supported, no messages will be emitted, but a log at FATAL
// severity will cause an abort.
//
// TODO(gfalcon): Come up with a better name for this method.
bool RawLoggingFullySupported();
// Function type for a raw_log customization hook for suppressing messages
// by severity, and for writing custom prefixes on non-suppressed messages.
//
// The installed hook is called for every raw log invocation. The message will
// be logged to stderr only if the hook returns true. FATAL errors will cause
// the process to abort, even if writing to stderr is suppressed. The hook is
// also provided with an output buffer, where it can write a custom log message
// prefix.
//
// The raw_log system does not allocate memory or grab locks. User-provided
// hooks must avoid these operations, and must not throw exceptions.
//
// 'severity' is the severity level of the message being written.
// 'file' and 'line' are the file and line number where the ABSL_RAW_LOG macro
// was located.
// 'buf' and 'buf_size' are pointers to the buffer and buffer size. If the
// hook writes a prefix, it must increment *buf and decrement *buf_size
// accordingly.
using LogFilterAndPrefixHook = bool (*)(absl::LogSeverity severity,
const char* file, int line, char** buf,
int* buf_size);
// Function type for a raw_log customization hook called to abort a process
// when a FATAL message is logged. If the provided AbortHook() returns, the
// logging system will call abort().
//
// 'file' and 'line' are the file and line number where the ABSL_RAW_LOG macro
// was located.
// The NUL-terminated logged message lives in the buffer between 'buf_start'
// and 'buf_end'. 'prefix_end' points to the first non-prefix character of the
// buffer (as written by the LogFilterAndPrefixHook.)
//
// The lifetime of the filename and message buffers will not end while the
// process remains alive.
using AbortHook = void (*)(const char* file, int line, const char* buf_start,
const char* prefix_end, const char* buf_end);
// Internal logging function for ABSL_INTERNAL_LOG to dispatch to.
//
// TODO(gfalcon): When string_view no longer depends on base, change this
// interface to take its message as a string_view instead.
using InternalLogFunction = void (*)(absl::LogSeverity severity,
const char* file, int line,
const std::string& message);
ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES ABSL_DLL extern base_internal::AtomicHook<
InternalLogFunction>
internal_log_function;
// Registers hooks of the above types. Only a single hook of each type may be
// registered. It is an error to call these functions multiple times with
// different input arguments.
//
// These functions are safe to call at any point during initialization; they do
// not block or malloc, and are async-signal safe.
void RegisterLogFilterAndPrefixHook(LogFilterAndPrefixHook func);
void RegisterAbortHook(AbortHook func);
void RegisterInternalLogFunction(InternalLogFunction func);
} // namespace raw_log_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_RAW_LOGGING_H_

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// 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.
//
// Core interfaces and definitions used by by low-level interfaces such as
// SpinLock.
#ifndef ABSL_BASE_INTERNAL_SCHEDULING_MODE_H_
#define ABSL_BASE_INTERNAL_SCHEDULING_MODE_H_
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Used to describe how a thread may be scheduled. Typically associated with
// the declaration of a resource supporting synchronized access.
//
// SCHEDULE_COOPERATIVE_AND_KERNEL:
// Specifies that when waiting, a cooperative thread (e.g. a Fiber) may
// reschedule (using base::scheduling semantics); allowing other cooperative
// threads to proceed.
//
// SCHEDULE_KERNEL_ONLY: (Also described as "non-cooperative")
// Specifies that no cooperative scheduling semantics may be used, even if the
// current thread is itself cooperatively scheduled. This means that
// cooperative threads will NOT allow other cooperative threads to execute in
// their place while waiting for a resource of this type. Host operating system
// semantics (e.g. a futex) may still be used.
//
// When optional, clients should strongly prefer SCHEDULE_COOPERATIVE_AND_KERNEL
// by default. SCHEDULE_KERNEL_ONLY should only be used for resources on which
// base::scheduling (e.g. the implementation of a Scheduler) may depend.
//
// NOTE: Cooperative resources may not be nested below non-cooperative ones.
// This means that it is invalid to to acquire a SCHEDULE_COOPERATIVE_AND_KERNEL
// resource if a SCHEDULE_KERNEL_ONLY resource is already held.
enum SchedulingMode {
SCHEDULE_KERNEL_ONLY = 0, // Allow scheduling only the host OS.
SCHEDULE_COOPERATIVE_AND_KERNEL, // Also allow cooperative scheduling.
};
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SCHEDULING_MODE_H_

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// 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.
#include "absl/base/internal/scoped_set_env.h"
#ifdef _WIN32
#include <windows.h>
#endif
#include <cstdlib>
#include "absl/base/internal/raw_logging.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
#ifdef _WIN32
const int kMaxEnvVarValueSize = 1024;
#endif
void SetEnvVar(const char* name, const char* value) {
#ifdef _WIN32
SetEnvironmentVariableA(name, value);
#else
if (value == nullptr) {
::unsetenv(name);
} else {
::setenv(name, value, 1);
}
#endif
}
} // namespace
ScopedSetEnv::ScopedSetEnv(const char* var_name, const char* new_value)
: var_name_(var_name), was_unset_(false) {
#ifdef _WIN32
char buf[kMaxEnvVarValueSize];
auto get_res = GetEnvironmentVariableA(var_name_.c_str(), buf, sizeof(buf));
ABSL_INTERNAL_CHECK(get_res < sizeof(buf), "value exceeds buffer size");
if (get_res == 0) {
was_unset_ = (GetLastError() == ERROR_ENVVAR_NOT_FOUND);
} else {
old_value_.assign(buf, get_res);
}
SetEnvironmentVariableA(var_name_.c_str(), new_value);
#else
const char* val = ::getenv(var_name_.c_str());
if (val == nullptr) {
was_unset_ = true;
} else {
old_value_ = val;
}
#endif
SetEnvVar(var_name_.c_str(), new_value);
}
ScopedSetEnv::~ScopedSetEnv() {
SetEnvVar(var_name_.c_str(), was_unset_ ? nullptr : old_value_.c_str());
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// 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_SCOPED_SET_ENV_H_
#define ABSL_BASE_INTERNAL_SCOPED_SET_ENV_H_
#include <string>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
class ScopedSetEnv {
public:
ScopedSetEnv(const char* var_name, const char* new_value);
~ScopedSetEnv();
private:
std::string var_name_;
std::string old_value_;
// True if the environment variable was initially not set.
bool was_unset_;
};
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SCOPED_SET_ENV_H_

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// 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.
#ifdef _WIN32
#include <windows.h>
#endif
#include "gtest/gtest.h"
#include "absl/base/internal/scoped_set_env.h"
namespace {
using absl::base_internal::ScopedSetEnv;
std::string GetEnvVar(const char* name) {
#ifdef _WIN32
char buf[1024];
auto get_res = GetEnvironmentVariableA(name, buf, sizeof(buf));
if (get_res >= sizeof(buf)) {
return "TOO_BIG";
}
if (get_res == 0) {
return "UNSET";
}
return std::string(buf, get_res);
#else
const char* val = ::getenv(name);
if (val == nullptr) {
return "UNSET";
}
return val;
#endif
}
TEST(ScopedSetEnvTest, SetNonExistingVarToString) {
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "UNSET");
{
ScopedSetEnv scoped_set("SCOPED_SET_ENV_TEST_VAR", "value");
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "value");
}
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "UNSET");
}
TEST(ScopedSetEnvTest, SetNonExistingVarToNull) {
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "UNSET");
{
ScopedSetEnv scoped_set("SCOPED_SET_ENV_TEST_VAR", nullptr);
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "UNSET");
}
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "UNSET");
}
TEST(ScopedSetEnvTest, SetExistingVarToString) {
ScopedSetEnv scoped_set("SCOPED_SET_ENV_TEST_VAR", "value");
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "value");
{
ScopedSetEnv scoped_set("SCOPED_SET_ENV_TEST_VAR", "new_value");
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "new_value");
}
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "value");
}
TEST(ScopedSetEnvTest, SetExistingVarToNull) {
ScopedSetEnv scoped_set("SCOPED_SET_ENV_TEST_VAR", "value");
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "value");
{
ScopedSetEnv scoped_set("SCOPED_SET_ENV_TEST_VAR", nullptr);
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "UNSET");
}
EXPECT_EQ(GetEnvVar("SCOPED_SET_ENV_TEST_VAR"), "value");
}
} // namespace

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// 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/config.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);
}
#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
// 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;
#endif
// 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 -- the lock word stores the amount of time
// that the current holder waited before acquiring the lock, not the wait
// time of any thread currently waiting to acquire it.
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.
} else if ((lock_value & kWaitTimeMask) == 0) {
// The lock is still held, without a waiter being marked, but something
// else about the lock word changed, causing our CAS to fail. For
// example, a new lock holder may have acquired the lock with
// kSpinLockDisabledScheduling set, whereas the previous holder had not
// set that flag. In this case, attempt again to mark ourselves as a
// waiter.
continue;
}
}
// 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 int64_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;
}
int64_t SpinLock::DecodeWaitCycles(uint32_t lock_value) {
// Cast to uint32_t first to ensure bits [63:32] are cleared.
const int64_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

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//
// 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.
//
// Most users requiring mutual exclusion should use Mutex.
// SpinLock is provided for use in two situations:
// - for use by Abseil internal code that Mutex itself depends on
// - for async signal safety (see below)
// SpinLock with a base_internal::SchedulingMode::SCHEDULE_KERNEL_ONLY is async
// signal safe. If a spinlock is used within a signal handler, all code that
// acquires the lock must ensure that the signal cannot arrive while they are
// holding the lock. Typically, this is done by blocking the signal.
//
// Threads waiting on a SpinLock may be woken in an arbitrary order.
#ifndef ABSL_BASE_INTERNAL_SPINLOCK_H_
#define ABSL_BASE_INTERNAL_SPINLOCK_H_
#include <atomic>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/const_init.h"
#include "absl/base/dynamic_annotations.h"
#include "absl/base/internal/low_level_scheduling.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/internal/tsan_mutex_interface.h"
#include "absl/base/thread_annotations.h"
namespace tcmalloc {
namespace tcmalloc_internal {
class AllocationGuardSpinLockHolder;
} // namespace tcmalloc_internal
} // namespace tcmalloc
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
class ABSL_LOCKABLE ABSL_ATTRIBUTE_WARN_UNUSED SpinLock {
public:
SpinLock() : lockword_(kSpinLockCooperative) {
ABSL_TSAN_MUTEX_CREATE(this, __tsan_mutex_not_static);
}
// Constructors that allow non-cooperative spinlocks to be created for use
// inside thread schedulers. Normal clients should not use these.
explicit SpinLock(base_internal::SchedulingMode mode);
// Constructor for global SpinLock instances. See absl/base/const_init.h.
constexpr SpinLock(absl::ConstInitType, base_internal::SchedulingMode mode)
: lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) {}
// For global SpinLock instances prefer trivial destructor when possible.
// Default but non-trivial destructor in some build configurations causes an
// extra static initializer.
#ifdef ABSL_INTERNAL_HAVE_TSAN_INTERFACE
~SpinLock() { ABSL_TSAN_MUTEX_DESTROY(this, __tsan_mutex_not_static); }
#else
~SpinLock() = default;
#endif
// Acquire this SpinLock.
inline void Lock() ABSL_EXCLUSIVE_LOCK_FUNCTION() {
ABSL_TSAN_MUTEX_PRE_LOCK(this, 0);
if (!TryLockImpl()) {
SlowLock();
}
ABSL_TSAN_MUTEX_POST_LOCK(this, 0, 0);
}
// Try to acquire this SpinLock without blocking and return true if the
// acquisition was successful. If the lock was not acquired, false is
// returned. If this SpinLock is free at the time of the call, TryLock
// will return true with high probability.
ABSL_MUST_USE_RESULT inline bool TryLock()
ABSL_EXCLUSIVE_TRYLOCK_FUNCTION(true) {
ABSL_TSAN_MUTEX_PRE_LOCK(this, __tsan_mutex_try_lock);
bool res = TryLockImpl();
ABSL_TSAN_MUTEX_POST_LOCK(
this, __tsan_mutex_try_lock | (res ? 0 : __tsan_mutex_try_lock_failed),
0);
return res;
}
// Release this SpinLock, which must be held by the calling thread.
inline void Unlock() ABSL_UNLOCK_FUNCTION() {
ABSL_TSAN_MUTEX_PRE_UNLOCK(this, 0);
uint32_t lock_value = lockword_.load(std::memory_order_relaxed);
lock_value = lockword_.exchange(lock_value & kSpinLockCooperative,
std::memory_order_release);
if ((lock_value & kSpinLockDisabledScheduling) != 0) {
base_internal::SchedulingGuard::EnableRescheduling(true);
}
if ((lock_value & kWaitTimeMask) != 0) {
// Collect contentionz profile info, and speed the wakeup of any waiter.
// The wait_cycles value indicates how long this thread spent waiting
// for the lock.
SlowUnlock(lock_value);
}
ABSL_TSAN_MUTEX_POST_UNLOCK(this, 0);
}
// Determine if the lock is held. When the lock is held by the invoking
// thread, true will always be returned. Intended to be used as
// CHECK(lock.IsHeld()).
ABSL_MUST_USE_RESULT inline bool IsHeld() const {
return (lockword_.load(std::memory_order_relaxed) & kSpinLockHeld) != 0;
}
// Return immediately if this thread holds the SpinLock exclusively.
// Otherwise, report an error by crashing with a diagnostic.
inline void AssertHeld() const ABSL_ASSERT_EXCLUSIVE_LOCK() {
if (!IsHeld()) {
ABSL_RAW_LOG(FATAL, "thread should hold the lock on SpinLock");
}
}
protected:
// These should not be exported except for testing.
// Store number of cycles between wait_start_time and wait_end_time in a
// lock value.
static uint32_t EncodeWaitCycles(int64_t wait_start_time,
int64_t wait_end_time);
// Extract number of wait cycles in a lock value.
static int64_t DecodeWaitCycles(uint32_t lock_value);
// Provide access to protected method above. Use for testing only.
friend struct SpinLockTest;
friend class tcmalloc::tcmalloc_internal::AllocationGuardSpinLockHolder;
private:
// lockword_ is used to store the following:
//
// bit[0] encodes whether a lock is being held.
// bit[1] encodes whether a lock uses cooperative scheduling.
// bit[2] encodes whether the current lock holder disabled scheduling when
// acquiring the lock. Only set when kSpinLockHeld is also set.
// bit[3:31] encodes time a lock spent on waiting as a 29-bit unsigned int.
// This is set by the lock holder to indicate how long it waited on
// the lock before eventually acquiring it. The number of cycles is
// encoded as a 29-bit unsigned int, or in the case that the current
// holder did not wait but another waiter is queued, the LSB
// (kSpinLockSleeper) is set. The implementation does not explicitly
// track the number of queued waiters beyond this. It must always be
// assumed that waiters may exist if the current holder was required to
// queue.
//
// Invariant: if the lock is not held, the value is either 0 or
// kSpinLockCooperative.
static constexpr uint32_t kSpinLockHeld = 1;
static constexpr uint32_t kSpinLockCooperative = 2;
static constexpr uint32_t kSpinLockDisabledScheduling = 4;
static constexpr uint32_t kSpinLockSleeper = 8;
// Includes kSpinLockSleeper.
static constexpr uint32_t kWaitTimeMask =
~(kSpinLockHeld | kSpinLockCooperative | kSpinLockDisabledScheduling);
// Returns true if the provided scheduling mode is cooperative.
static constexpr bool IsCooperative(
base_internal::SchedulingMode scheduling_mode) {
return scheduling_mode == base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL;
}
bool IsCooperative() const {
return lockword_.load(std::memory_order_relaxed) & kSpinLockCooperative;
}
uint32_t TryLockInternal(uint32_t lock_value, uint32_t wait_cycles);
void SlowLock() ABSL_ATTRIBUTE_COLD;
void SlowUnlock(uint32_t lock_value) ABSL_ATTRIBUTE_COLD;
uint32_t SpinLoop();
inline bool TryLockImpl() {
uint32_t lock_value = lockword_.load(std::memory_order_relaxed);
return (TryLockInternal(lock_value, 0) & kSpinLockHeld) == 0;
}
std::atomic<uint32_t> lockword_;
SpinLock(const SpinLock&) = delete;
SpinLock& operator=(const SpinLock&) = delete;
};
// Corresponding locker object that arranges to acquire a spinlock for
// the duration of a C++ scope.
//
// TODO(b/176172494): Use only [[nodiscard]] when baseline is raised.
// TODO(b/6695610): Remove forward declaration when #ifdef is no longer needed.
#if ABSL_HAVE_CPP_ATTRIBUTE(nodiscard)
class [[nodiscard]] SpinLockHolder;
#else
class ABSL_MUST_USE_RESULT ABSL_ATTRIBUTE_TRIVIAL_ABI SpinLockHolder;
#endif
class ABSL_SCOPED_LOCKABLE SpinLockHolder {
public:
inline explicit SpinLockHolder(SpinLock* l) ABSL_EXCLUSIVE_LOCK_FUNCTION(l)
: lock_(l) {
l->Lock();
}
inline ~SpinLockHolder() ABSL_UNLOCK_FUNCTION() { lock_->Unlock(); }
SpinLockHolder(const SpinLockHolder&) = delete;
SpinLockHolder& operator=(const SpinLockHolder&) = delete;
private:
SpinLock* lock_;
};
// Register a hook for profiling support.
//
// The function pointer registered here will be called whenever a spinlock is
// contended. The callback is given an opaque handle to the contended spinlock
// and the number of wait cycles. This is thread-safe, but only a single
// profiler can be registered. It is an error to call this function multiple
// times with different arguments.
void RegisterSpinLockProfiler(void (*fn)(const void* lock,
int64_t wait_cycles));
//------------------------------------------------------------------------------
// Public interface ends here.
//------------------------------------------------------------------------------
// If (result & kSpinLockHeld) == 0, then *this was successfully locked.
// Otherwise, returns last observed value for lockword_.
inline uint32_t SpinLock::TryLockInternal(uint32_t lock_value,
uint32_t wait_cycles) {
if ((lock_value & kSpinLockHeld) != 0) {
return lock_value;
}
uint32_t sched_disabled_bit = 0;
if ((lock_value & kSpinLockCooperative) == 0) {
// For non-cooperative locks we must make sure we mark ourselves as
// non-reschedulable before we attempt to CompareAndSwap.
if (base_internal::SchedulingGuard::DisableRescheduling()) {
sched_disabled_bit = kSpinLockDisabledScheduling;
}
}
if (!lockword_.compare_exchange_strong(
lock_value,
kSpinLockHeld | lock_value | wait_cycles | sched_disabled_bit,
std::memory_order_acquire, std::memory_order_relaxed)) {
base_internal::SchedulingGuard::EnableRescheduling(sched_disabled_bit != 0);
}
return lock_value;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SPINLOCK_H_

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// 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.
//
// This file is an Akaros-specific part of spinlock_wait.cc
#include <atomic>
#include "absl/base/internal/scheduling_mode.h"
extern "C" {
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t>* /* lock_word */, uint32_t /* value */,
int /* loop */, absl::base_internal::SchedulingMode /* mode */) {
// In Akaros, one must take care not to call anything that could cause a
// malloc(), a blocking system call, or a uthread_yield() while holding a
// spinlock. Our callers assume will not call into libraries or other
// arbitrary code.
}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t>* /* lock_word */, bool /* all */) {}
} // extern "C"

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// 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.
// See also //absl/synchronization:mutex_benchmark for a comparison of SpinLock
// and Mutex performance under varying levels of contention.
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/internal/spinlock.h"
#include "absl/base/no_destructor.h"
#include "absl/synchronization/internal/create_thread_identity.h"
#include "benchmark/benchmark.h"
namespace {
template <absl::base_internal::SchedulingMode scheduling_mode>
static void BM_TryLock(benchmark::State& state) {
// Ensure a ThreadIdentity is installed so that KERNEL_ONLY has an effect.
ABSL_INTERNAL_CHECK(
absl::synchronization_internal::GetOrCreateCurrentThreadIdentity() !=
nullptr,
"GetOrCreateCurrentThreadIdentity() failed");
static absl::NoDestructor<absl::base_internal::SpinLock> spinlock(
scheduling_mode);
for (auto _ : state) {
if (spinlock->TryLock()) spinlock->Unlock();
}
}
template <absl::base_internal::SchedulingMode scheduling_mode>
static void BM_SpinLock(benchmark::State& state) {
// Ensure a ThreadIdentity is installed so that KERNEL_ONLY has an effect.
ABSL_INTERNAL_CHECK(
absl::synchronization_internal::GetOrCreateCurrentThreadIdentity() !=
nullptr,
"GetOrCreateCurrentThreadIdentity() failed");
static absl::NoDestructor<absl::base_internal::SpinLock> spinlock(
scheduling_mode);
for (auto _ : state) {
absl::base_internal::SpinLockHolder holder(spinlock.get());
}
}
BENCHMARK_TEMPLATE(BM_SpinLock,
absl::base_internal::SCHEDULE_KERNEL_ONLY)
->UseRealTime()
->Threads(1)
->ThreadPerCpu();
BENCHMARK_TEMPLATE(BM_SpinLock,
absl::base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL)
->UseRealTime()
->Threads(1)
->ThreadPerCpu();
BENCHMARK_TEMPLATE(BM_TryLock, absl::base_internal::SCHEDULE_KERNEL_ONLY)
->UseRealTime()
->Threads(1)
->ThreadPerCpu();
BENCHMARK_TEMPLATE(BM_TryLock,
absl::base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL)
->UseRealTime()
->Threads(1)
->ThreadPerCpu();
} // namespace

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// 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 ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t> *w, uint32_t value, int,
absl::base_internal::SchedulingMode) {
absl::base_internal::ErrnoSaver errno_saver;
syscall(SYS_futex, w, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, value, nullptr);
}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t> *w, bool all) {
syscall(SYS_futex, w, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, all ? INT_MAX : 1, 0);
}
} // extern "C"

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// 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.
//
// This file is a Posix-specific part of spinlock_wait.cc
#include <sched.h>
#include <atomic>
#include <ctime>
#include "absl/base/internal/errno_saver.h"
#include "absl/base/internal/scheduling_mode.h"
#include "absl/base/port.h"
extern "C" {
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t>* /* lock_word */, uint32_t /* value */, int loop,
absl::base_internal::SchedulingMode /* mode */) {
absl::base_internal::ErrnoSaver errno_saver;
if (loop == 0) {
} else if (loop == 1) {
sched_yield();
} else {
struct timespec tm;
tm.tv_sec = 0;
tm.tv_nsec = absl::base_internal::SpinLockSuggestedDelayNS(loop);
nanosleep(&tm, nullptr);
}
}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t>* /* lock_word */, bool /* all */) {}
} // extern "C"

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// 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.
// The OS-specific header included below must provide two calls:
// AbslInternalSpinLockDelay() and AbslInternalSpinLockWake().
// See spinlock_wait.h for the specs.
#include <atomic>
#include <cstdint>
#include "absl/base/internal/spinlock_wait.h"
#if defined(_WIN32)
#include "absl/base/internal/spinlock_win32.inc"
#elif defined(__linux__)
#include "absl/base/internal/spinlock_linux.inc"
#elif defined(__akaros__)
#include "absl/base/internal/spinlock_akaros.inc"
#else
#include "absl/base/internal/spinlock_posix.inc"
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// See spinlock_wait.h for spec.
uint32_t SpinLockWait(std::atomic<uint32_t> *w, int n,
const SpinLockWaitTransition trans[],
base_internal::SchedulingMode scheduling_mode) {
int loop = 0;
for (;;) {
uint32_t v = w->load(std::memory_order_acquire);
int i;
for (i = 0; i != n && v != trans[i].from; i++) {
}
if (i == n) {
SpinLockDelay(w, v, ++loop, scheduling_mode); // no matching transition
} else if (trans[i].to == v || // null transition
w->compare_exchange_strong(v, trans[i].to,
std::memory_order_acquire,
std::memory_order_relaxed)) {
if (trans[i].done) return v;
}
}
}
static std::atomic<uint64_t> delay_rand;
// Return a suggested delay in nanoseconds for iteration number "loop"
int SpinLockSuggestedDelayNS(int loop) {
// Weak pseudo-random number generator to get some spread between threads
// when many are spinning.
uint64_t r = delay_rand.load(std::memory_order_relaxed);
r = 0x5deece66dLL * r + 0xb; // numbers from nrand48()
delay_rand.store(r, std::memory_order_relaxed);
if (loop < 0 || loop > 32) { // limit loop to 0..32
loop = 32;
}
const int kMinDelay = 128 << 10; // 128us
// Double delay every 8 iterations, up to 16x (2ms).
int delay = kMinDelay << (loop / 8);
// Randomize in delay..2*delay range, for resulting 128us..4ms range.
return delay | ((delay - 1) & static_cast<int>(r));
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
#ifndef ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_
#define ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_
// Operations to make atomic transitions on a word, and to allow
// waiting for those transitions to become possible.
#include <stdint.h>
#include <atomic>
#include "absl/base/internal/scheduling_mode.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// SpinLockWait() waits until it can perform one of several transitions from
// "from" to "to". It returns when it performs a transition where done==true.
struct SpinLockWaitTransition {
uint32_t from;
uint32_t to;
bool done;
};
// Wait until *w can transition from trans[i].from to trans[i].to for some i
// satisfying 0<=i<n && trans[i].done, atomically make the transition,
// then return the old value of *w. Make any other atomic transitions
// where !trans[i].done, but continue waiting.
//
// Wakeups for threads blocked on SpinLockWait do not respect priorities.
uint32_t SpinLockWait(std::atomic<uint32_t> *w, int n,
const SpinLockWaitTransition trans[],
SchedulingMode scheduling_mode);
// If possible, wake some thread that has called SpinLockDelay(w, ...). If `all`
// is true, wake all such threads. On some systems, this may be a no-op; on
// those systems, threads calling SpinLockDelay() will always wake eventually
// even if SpinLockWake() is never called.
void SpinLockWake(std::atomic<uint32_t> *w, bool all);
// Wait for an appropriate spin delay on iteration "loop" of a
// spin loop on location *w, whose previously observed value was "value".
// SpinLockDelay() may do nothing, may yield the CPU, may sleep a clock tick,
// or may wait for a call to SpinLockWake(w).
void SpinLockDelay(std::atomic<uint32_t> *w, uint32_t value, int loop,
base_internal::SchedulingMode scheduling_mode);
// Helper used by AbslInternalSpinLockDelay.
// Returns a suggested delay in nanoseconds for iteration number "loop".
int SpinLockSuggestedDelayNS(int loop);
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
// In some build configurations we pass --detect-odr-violations to the
// gold linker. This causes it to flag weak symbol overrides as ODR
// violations. Because ODR only applies to C++ and not C,
// --detect-odr-violations ignores symbols not mangled with C++ names.
// By changing our extension points to be extern "C", we dodge this
// check.
extern "C" {
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(std::atomic<uint32_t> *w,
bool all);
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t> *w, uint32_t value, int loop,
absl::base_internal::SchedulingMode scheduling_mode);
}
inline void absl::base_internal::SpinLockWake(std::atomic<uint32_t> *w,
bool all) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(w, all);
}
inline void absl::base_internal::SpinLockDelay(
std::atomic<uint32_t> *w, uint32_t value, int loop,
absl::base_internal::SchedulingMode scheduling_mode) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)
(w, value, loop, scheduling_mode);
}
#endif // ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_

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// 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.
//
// This file is a Win32-specific part of spinlock_wait.cc
#include <windows.h>
#include <atomic>
#include "absl/base/internal/scheduling_mode.h"
extern "C" {
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
std::atomic<uint32_t>* /* lock_word */, uint32_t /* value */, int loop,
absl::base_internal::SchedulingMode /* mode */) {
if (loop == 0) {
} else if (loop == 1) {
Sleep(0);
} else {
// SpinLockSuggestedDelayNS() always returns a positive integer, so this
// static_cast is safe.
Sleep(static_cast<DWORD>(
absl::base_internal::SpinLockSuggestedDelayNS(loop) / 1000000));
}
}
void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
std::atomic<uint32_t>* /* lock_word */, bool /* all */) {}
} // extern "C"

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// Copyright 2020 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/strerror.h"
#include <array>
#include <cerrno>
#include <cstddef>
#include <cstdio>
#include <cstring>
#include <string>
#include <type_traits>
#include "absl/base/internal/errno_saver.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
const char* StrErrorAdaptor(int errnum, char* buf, size_t buflen) {
#if defined(_WIN32)
int rc = strerror_s(buf, buflen, errnum);
buf[buflen - 1] = '\0'; // guarantee NUL termination
if (rc == 0 && strncmp(buf, "Unknown error", buflen) == 0) *buf = '\0';
return buf;
#else
// The type of `ret` is platform-specific; both of these branches must compile
// either way but only one will execute on any given platform:
auto ret = strerror_r(errnum, buf, buflen);
if (std::is_same<decltype(ret), int>::value) {
// XSI `strerror_r`; `ret` is `int`:
if (ret) *buf = '\0';
return buf;
} else {
// GNU `strerror_r`; `ret` is `char *`:
return reinterpret_cast<const char*>(ret);
}
#endif
}
std::string StrErrorInternal(int errnum) {
char buf[100];
const char* str = StrErrorAdaptor(errnum, buf, sizeof buf);
if (*str == '\0') {
snprintf(buf, sizeof buf, "Unknown error %d", errnum);
str = buf;
}
return str;
}
// kSysNerr is the number of errors from a recent glibc. `StrError()` falls back
// to `StrErrorAdaptor()` if the value is larger than this.
constexpr int kSysNerr = 135;
std::array<std::string, kSysNerr>* NewStrErrorTable() {
auto* table = new std::array<std::string, kSysNerr>;
for (size_t i = 0; i < table->size(); ++i) {
(*table)[i] = StrErrorInternal(static_cast<int>(i));
}
return table;
}
} // namespace
std::string StrError(int errnum) {
absl::base_internal::ErrnoSaver errno_saver;
static const auto* table = NewStrErrorTable();
if (errnum >= 0 && static_cast<size_t>(errnum) < table->size()) {
return (*table)[static_cast<size_t>(errnum)];
}
return StrErrorInternal(errnum);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// Copyright 2020 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_STRERROR_H_
#define ABSL_BASE_INTERNAL_STRERROR_H_
#include <string>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// A portable and thread-safe alternative to C89's `strerror`.
//
// The C89 specification of `strerror` is not suitable for use in a
// multi-threaded application as the returned string may be changed by calls to
// `strerror` from another thread. The many non-stdlib alternatives differ
// enough in their names, availability, and semantics to justify this wrapper
// around them. `errno` will not be modified by a call to `absl::StrError`.
std::string StrError(int errnum);
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_STRERROR_H_

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// Copyright 2020 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 <cerrno>
#include <cstdio>
#include <string>
#include "absl/base/internal/strerror.h"
#include "benchmark/benchmark.h"
namespace {
void BM_AbslStrError(benchmark::State& state) {
for (auto _ : state) {
benchmark::DoNotOptimize(absl::base_internal::StrError(ERANGE));
}
}
BENCHMARK(BM_AbslStrError);
} // namespace

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// Copyright 2020 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/strerror.h"
#include <atomic>
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <string>
#include <thread> // NOLINT(build/c++11)
#include <vector>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/strings/match.h"
namespace {
using ::testing::AnyOf;
using ::testing::Eq;
TEST(StrErrorTest, ValidErrorCode) {
errno = ERANGE;
EXPECT_THAT(absl::base_internal::StrError(EDOM), Eq(strerror(EDOM)));
EXPECT_THAT(errno, Eq(ERANGE));
}
TEST(StrErrorTest, InvalidErrorCode) {
errno = ERANGE;
EXPECT_THAT(absl::base_internal::StrError(-1),
AnyOf(Eq("No error information"), Eq("Unknown error -1")));
EXPECT_THAT(errno, Eq(ERANGE));
}
TEST(StrErrorTest, MultipleThreads) {
// In this test, we will start up 2 threads and have each one call
// StrError 1000 times, each time with a different errnum. We
// expect that StrError(errnum) will return a string equal to the
// one returned by strerror(errnum), if the code is known. Since
// strerror is known to be thread-hostile, collect all the expected
// strings up front.
const int kNumCodes = 1000;
std::vector<std::string> expected_strings(kNumCodes);
for (int i = 0; i < kNumCodes; ++i) {
expected_strings[i] = strerror(i);
}
std::atomic_int counter(0);
auto thread_fun = [&]() {
for (int i = 0; i < kNumCodes; ++i) {
++counter;
errno = ERANGE;
const std::string value = absl::base_internal::StrError(i);
// EXPECT_* could change errno. Stash it first.
int check_err = errno;
EXPECT_THAT(check_err, Eq(ERANGE));
// Only the GNU implementation is guaranteed to provide the
// string "Unknown error nnn". POSIX doesn't say anything.
if (!absl::StartsWith(value, "Unknown error ")) {
EXPECT_THAT(value, Eq(expected_strings[i]));
}
}
};
const int kNumThreads = 100;
std::vector<std::thread> threads;
for (int i = 0; i < kNumThreads; ++i) {
threads.push_back(std::thread(thread_fun));
}
for (auto& thread : threads) {
thread.join();
}
EXPECT_THAT(counter, Eq(kNumThreads * kNumCodes));
}
} // namespace

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// 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/sysinfo.h"
#include "absl/base/attributes.h"
#ifdef _WIN32
#include <windows.h>
#else
#include <fcntl.h>
#include <pthread.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#endif
#ifdef __linux__
#include <sys/syscall.h>
#endif
#if defined(__APPLE__) || defined(__FreeBSD__)
#include <sys/sysctl.h>
#endif
#ifdef __FreeBSD__
#include <pthread_np.h>
#endif
#ifdef __NetBSD__
#include <lwp.h>
#endif
#if defined(__myriad2__)
#include <rtems.h>
#endif
#if defined(__Fuchsia__)
#include <zircon/process.h>
#endif
#include <string.h>
#include <cassert>
#include <cerrno>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <limits>
#include <thread> // NOLINT(build/c++11)
#include <utility>
#include <vector>
#include "absl/base/call_once.h"
#include "absl/base/config.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/spinlock.h"
#include "absl/base/internal/unscaledcycleclock.h"
#include "absl/base/thread_annotations.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
#if defined(_WIN32)
// Returns number of bits set in `bitMask`
DWORD Win32CountSetBits(ULONG_PTR bitMask) {
for (DWORD bitSetCount = 0; ; ++bitSetCount) {
if (bitMask == 0) return bitSetCount;
bitMask &= bitMask - 1;
}
}
// Returns the number of logical CPUs using GetLogicalProcessorInformation(), or
// 0 if the number of processors is not available or can not be computed.
// https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getlogicalprocessorinformation
int Win32NumCPUs() {
#pragma comment(lib, "kernel32.lib")
using Info = SYSTEM_LOGICAL_PROCESSOR_INFORMATION;
DWORD info_size = sizeof(Info);
Info* info(static_cast<Info*>(malloc(info_size)));
if (info == nullptr) return 0;
bool success = GetLogicalProcessorInformation(info, &info_size);
if (!success && GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
free(info);
info = static_cast<Info*>(malloc(info_size));
if (info == nullptr) return 0;
success = GetLogicalProcessorInformation(info, &info_size);
}
DWORD logicalProcessorCount = 0;
if (success) {
Info* ptr = info;
DWORD byteOffset = 0;
while (byteOffset + sizeof(Info) <= info_size) {
switch (ptr->Relationship) {
case RelationProcessorCore:
logicalProcessorCount += Win32CountSetBits(ptr->ProcessorMask);
break;
case RelationNumaNode:
case RelationCache:
case RelationProcessorPackage:
// Ignore other entries
break;
default:
// Ignore unknown entries
break;
}
byteOffset += sizeof(Info);
ptr++;
}
}
free(info);
return static_cast<int>(logicalProcessorCount);
}
#endif
} // namespace
static int GetNumCPUs() {
#if defined(__myriad2__)
return 1;
#elif defined(_WIN32)
const int hardware_concurrency = Win32NumCPUs();
return hardware_concurrency ? hardware_concurrency : 1;
#elif defined(_AIX)
return sysconf(_SC_NPROCESSORS_ONLN);
#else
// Other possibilities:
// - Read /sys/devices/system/cpu/online and use cpumask_parse()
// - sysconf(_SC_NPROCESSORS_ONLN)
return static_cast<int>(std::thread::hardware_concurrency());
#endif
}
#if defined(_WIN32)
static double GetNominalCPUFrequency() {
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP) && \
!WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
// UWP apps don't have access to the registry and currently don't provide an
// API informing about CPU nominal frequency.
return 1.0;
#else
#pragma comment(lib, "advapi32.lib") // For Reg* functions.
HKEY key;
// Use the Reg* functions rather than the SH functions because shlwapi.dll
// pulls in gdi32.dll which makes process destruction much more costly.
if (RegOpenKeyExA(HKEY_LOCAL_MACHINE,
"HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0", 0,
KEY_READ, &key) == ERROR_SUCCESS) {
DWORD type = 0;
DWORD data = 0;
DWORD data_size = sizeof(data);
auto result = RegQueryValueExA(key, "~MHz", nullptr, &type,
reinterpret_cast<LPBYTE>(&data), &data_size);
RegCloseKey(key);
if (result == ERROR_SUCCESS && type == REG_DWORD &&
data_size == sizeof(data)) {
return data * 1e6; // Value is MHz.
}
}
return 1.0;
#endif // WINAPI_PARTITION_APP && !WINAPI_PARTITION_DESKTOP
}
#elif defined(CTL_HW) && defined(HW_CPU_FREQ)
static double GetNominalCPUFrequency() {
unsigned freq;
size_t size = sizeof(freq);
int mib[2] = {CTL_HW, HW_CPU_FREQ};
if (sysctl(mib, 2, &freq, &size, nullptr, 0) == 0) {
return static_cast<double>(freq);
}
return 1.0;
}
#else
// Helper function for reading a long from a file. Returns true if successful
// and the memory location pointed to by value is set to the value read.
static bool ReadLongFromFile(const char *file, long *value) {
bool ret = false;
#if defined(_POSIX_C_SOURCE)
const int file_mode = (O_RDONLY | O_CLOEXEC);
#else
const int file_mode = O_RDONLY;
#endif
int fd = open(file, file_mode);
if (fd != -1) {
char line[1024];
char *err;
memset(line, '\0', sizeof(line));
ssize_t len;
do {
len = read(fd, line, sizeof(line) - 1);
} while (len < 0 && errno == EINTR);
if (len <= 0) {
ret = false;
} else {
const long temp_value = strtol(line, &err, 10);
if (line[0] != '\0' && (*err == '\n' || *err == '\0')) {
*value = temp_value;
ret = true;
}
}
close(fd);
}
return ret;
}
#if defined(ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY)
// Reads a monotonic time source and returns a value in
// nanoseconds. The returned value uses an arbitrary epoch, not the
// Unix epoch.
static int64_t ReadMonotonicClockNanos() {
struct timespec t;
#ifdef CLOCK_MONOTONIC_RAW
int rc = clock_gettime(CLOCK_MONOTONIC_RAW, &t);
#else
int rc = clock_gettime(CLOCK_MONOTONIC, &t);
#endif
if (rc != 0) {
ABSL_INTERNAL_LOG(
FATAL, "clock_gettime() failed: (" + std::to_string(errno) + ")");
}
return int64_t{t.tv_sec} * 1000000000 + t.tv_nsec;
}
class UnscaledCycleClockWrapperForInitializeFrequency {
public:
static int64_t Now() { return base_internal::UnscaledCycleClock::Now(); }
};
struct TimeTscPair {
int64_t time; // From ReadMonotonicClockNanos().
int64_t tsc; // From UnscaledCycleClock::Now().
};
// Returns a pair of values (monotonic kernel time, TSC ticks) that
// approximately correspond to each other. This is accomplished by
// doing several reads and picking the reading with the lowest
// latency. This approach is used to minimize the probability that
// our thread was preempted between clock reads.
static TimeTscPair GetTimeTscPair() {
int64_t best_latency = std::numeric_limits<int64_t>::max();
TimeTscPair best;
for (int i = 0; i < 10; ++i) {
int64_t t0 = ReadMonotonicClockNanos();
int64_t tsc = UnscaledCycleClockWrapperForInitializeFrequency::Now();
int64_t t1 = ReadMonotonicClockNanos();
int64_t latency = t1 - t0;
if (latency < best_latency) {
best_latency = latency;
best.time = t0;
best.tsc = tsc;
}
}
return best;
}
// Measures and returns the TSC frequency by taking a pair of
// measurements approximately `sleep_nanoseconds` apart.
static double MeasureTscFrequencyWithSleep(int sleep_nanoseconds) {
auto t0 = GetTimeTscPair();
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = sleep_nanoseconds;
while (nanosleep(&ts, &ts) != 0 && errno == EINTR) {}
auto t1 = GetTimeTscPair();
double elapsed_ticks = t1.tsc - t0.tsc;
double elapsed_time = (t1.time - t0.time) * 1e-9;
return elapsed_ticks / elapsed_time;
}
// Measures and returns the TSC frequency by calling
// MeasureTscFrequencyWithSleep(), doubling the sleep interval until the
// frequency measurement stabilizes.
static double MeasureTscFrequency() {
double last_measurement = -1.0;
int sleep_nanoseconds = 1000000; // 1 millisecond.
for (int i = 0; i < 8; ++i) {
double measurement = MeasureTscFrequencyWithSleep(sleep_nanoseconds);
if (measurement * 0.99 < last_measurement &&
last_measurement < measurement * 1.01) {
// Use the current measurement if it is within 1% of the
// previous measurement.
return measurement;
}
last_measurement = measurement;
sleep_nanoseconds *= 2;
}
return last_measurement;
}
#endif // ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
static double GetNominalCPUFrequency() {
long freq = 0;
// Google's production kernel has a patch to export the TSC
// frequency through sysfs. If the kernel is exporting the TSC
// frequency use that. There are issues where cpuinfo_max_freq
// cannot be relied on because the BIOS may be exporting an invalid
// p-state (on x86) or p-states may be used to put the processor in
// a new mode (turbo mode). Essentially, those frequencies cannot
// always be relied upon. The same reasons apply to /proc/cpuinfo as
// well.
if (ReadLongFromFile("/sys/devices/system/cpu/cpu0/tsc_freq_khz", &freq)) {
return freq * 1e3; // Value is kHz.
}
#if defined(ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY)
// On these platforms, the TSC frequency is the nominal CPU
// frequency. But without having the kernel export it directly
// though /sys/devices/system/cpu/cpu0/tsc_freq_khz, there is no
// other way to reliably get the TSC frequency, so we have to
// measure it ourselves. Some CPUs abuse cpuinfo_max_freq by
// exporting "fake" frequencies for implementing new features. For
// example, Intel's turbo mode is enabled by exposing a p-state
// value with a higher frequency than that of the real TSC
// rate. Because of this, we prefer to measure the TSC rate
// ourselves on i386 and x86-64.
return MeasureTscFrequency();
#else
// If CPU scaling is in effect, we want to use the *maximum*
// frequency, not whatever CPU speed some random processor happens
// to be using now.
if (ReadLongFromFile("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq",
&freq)) {
return freq * 1e3; // Value is kHz.
}
return 1.0;
#endif // !ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
}
#endif
ABSL_CONST_INIT static once_flag init_num_cpus_once;
ABSL_CONST_INIT static int num_cpus = 0;
// NumCPUs() may be called before main() and before malloc is properly
// initialized, therefore this must not allocate memory.
int NumCPUs() {
base_internal::LowLevelCallOnce(
&init_num_cpus_once, []() { num_cpus = GetNumCPUs(); });
return num_cpus;
}
// A default frequency of 0.0 might be dangerous if it is used in division.
ABSL_CONST_INIT static once_flag init_nominal_cpu_frequency_once;
ABSL_CONST_INIT static double nominal_cpu_frequency = 1.0;
// NominalCPUFrequency() may be called before main() and before malloc is
// properly initialized, therefore this must not allocate memory.
double NominalCPUFrequency() {
base_internal::LowLevelCallOnce(
&init_nominal_cpu_frequency_once,
[]() { nominal_cpu_frequency = GetNominalCPUFrequency(); });
return nominal_cpu_frequency;
}
#if defined(_WIN32)
pid_t GetTID() {
return pid_t{GetCurrentThreadId()};
}
#elif defined(__linux__)
#ifndef SYS_gettid
#define SYS_gettid __NR_gettid
#endif
pid_t GetTID() {
return static_cast<pid_t>(syscall(SYS_gettid));
}
#elif defined(__akaros__)
pid_t GetTID() {
// Akaros has a concept of "vcore context", which is the state the program
// is forced into when we need to make a user-level scheduling decision, or
// run a signal handler. This is analogous to the interrupt context that a
// CPU might enter if it encounters some kind of exception.
//
// There is no current thread context in vcore context, but we need to give
// a reasonable answer if asked for a thread ID (e.g., in a signal handler).
// Thread 0 always exists, so if we are in vcore context, we return that.
//
// Otherwise, we know (since we are using pthreads) that the uthread struct
// current_uthread is pointing to is the first element of a
// struct pthread_tcb, so we extract and return the thread ID from that.
//
// TODO(dcross): Akaros anticipates moving the thread ID to the uthread
// structure at some point. We should modify this code to remove the cast
// when that happens.
if (in_vcore_context())
return 0;
return reinterpret_cast<struct pthread_tcb *>(current_uthread)->id;
}
#elif defined(__myriad2__)
pid_t GetTID() {
uint32_t tid;
rtems_task_ident(RTEMS_SELF, 0, &tid);
return tid;
}
#elif defined(__APPLE__)
pid_t GetTID() {
uint64_t tid;
// `nullptr` here implies this thread. This only fails if the specified
// thread is invalid or the pointer-to-tid is null, so we needn't worry about
// it.
pthread_threadid_np(nullptr, &tid);
return static_cast<pid_t>(tid);
}
#elif defined(__FreeBSD__)
pid_t GetTID() { return static_cast<pid_t>(pthread_getthreadid_np()); }
#elif defined(__OpenBSD__)
pid_t GetTID() { return getthrid(); }
#elif defined(__NetBSD__)
pid_t GetTID() { return static_cast<pid_t>(_lwp_self()); }
#elif defined(__native_client__)
pid_t GetTID() {
auto* thread = pthread_self();
static_assert(sizeof(pid_t) == sizeof(thread),
"In NaCL int expected to be the same size as a pointer");
return reinterpret_cast<pid_t>(thread);
}
#elif defined(__Fuchsia__)
pid_t GetTID() {
// Use our thread handle as the TID, which should be unique within this
// process (but may not be globally unique). The handle value was chosen over
// a kernel object ID (KOID) because zx_handle_t (32-bits) can be cast to a
// pid_t type without loss of precision, but a zx_koid_t (64-bits) cannot.
return static_cast<pid_t>(zx_thread_self());
}
#else
// Fallback implementation of `GetTID` using `pthread_self`.
pid_t GetTID() {
// `pthread_t` need not be arithmetic per POSIX; platforms where it isn't
// should be handled above.
return static_cast<pid_t>(pthread_self());
}
#endif
// GetCachedTID() caches the thread ID in thread-local storage (which is a
// userspace construct) to avoid unnecessary system calls. Without this caching,
// it can take roughly 98ns, while it takes roughly 1ns with this caching.
pid_t GetCachedTID() {
#ifdef ABSL_HAVE_THREAD_LOCAL
static thread_local pid_t thread_id = GetTID();
return thread_id;
#else
return GetTID();
#endif // ABSL_HAVE_THREAD_LOCAL
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
//
// This file includes routines to find out characteristics
// of the machine a program is running on. It is undoubtedly
// system-dependent.
// Functions listed here that accept a pid_t as an argument act on the
// current process if the pid_t argument is 0
// All functions here are thread-hostile due to file caching unless
// commented otherwise.
#ifndef ABSL_BASE_INTERNAL_SYSINFO_H_
#define ABSL_BASE_INTERNAL_SYSINFO_H_
#ifndef _WIN32
#include <sys/types.h>
#endif
#include <cstdint>
#include "absl/base/config.h"
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Nominal core processor cycles per second of each processor. This is _not_
// necessarily the frequency of the CycleClock counter (see cycleclock.h)
// Thread-safe.
double NominalCPUFrequency();
// Number of logical processors (hyperthreads) in system. Thread-safe.
int NumCPUs();
// Return the thread id of the current thread, as told by the system.
// No two currently-live threads implemented by the OS shall have the same ID.
// Thread ids of exited threads may be reused. Multiple user-level threads
// may have the same thread ID if multiplexed on the same OS thread.
//
// On Linux, you may send a signal to the resulting ID with kill(). However,
// it is recommended for portability that you use pthread_kill() instead.
#ifdef _WIN32
// On Windows, process id and thread id are of the same type according to the
// return types of GetProcessId() and GetThreadId() are both DWORD, an unsigned
// 32-bit type.
using pid_t = uint32_t;
#endif
pid_t GetTID();
// Like GetTID(), but caches the result in thread-local storage in order
// to avoid unnecessary system calls. Note that there are some cases where
// one must call through to GetTID directly, which is why this exists as a
// separate function. For example, GetCachedTID() is not safe to call in
// an asynchronous signal-handling context nor right after a call to fork().
pid_t GetCachedTID();
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SYSINFO_H_

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// 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/sysinfo.h"
#ifndef _WIN32
#include <sys/types.h>
#include <unistd.h>
#endif
#include <thread> // NOLINT(build/c++11)
#include <unordered_set>
#include <vector>
#include "gtest/gtest.h"
#include "absl/synchronization/barrier.h"
#include "absl/synchronization/mutex.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
TEST(SysinfoTest, NumCPUs) {
EXPECT_NE(NumCPUs(), 0)
<< "NumCPUs() should not have the default value of 0";
}
TEST(SysinfoTest, GetTID) {
EXPECT_EQ(GetTID(), GetTID()); // Basic compile and equality test.
#ifdef __native_client__
// Native Client has a race condition bug that leads to memory
// exaustion when repeatedly creating and joining threads.
// https://bugs.chromium.org/p/nativeclient/issues/detail?id=1027
return;
#endif
// Test that TIDs are unique to each thread.
// Uses a few loops to exercise implementations that reallocate IDs.
for (int i = 0; i < 10; ++i) {
constexpr int kNumThreads = 10;
Barrier all_threads_done(kNumThreads);
std::vector<std::thread> threads;
Mutex mutex;
std::unordered_set<pid_t> tids;
for (int j = 0; j < kNumThreads; ++j) {
threads.push_back(std::thread([&]() {
pid_t id = GetTID();
{
MutexLock lock(&mutex);
ASSERT_TRUE(tids.find(id) == tids.end());
tids.insert(id);
}
// We can't simply join the threads here. The threads need to
// be alive otherwise the TID might have been reallocated to
// another live thread.
all_threads_done.Block();
}));
}
for (auto& thread : threads) {
thread.join();
}
}
}
#ifdef __linux__
TEST(SysinfoTest, LinuxGetTID) {
// On Linux, for the main thread, GetTID()==getpid() is guaranteed by the API.
EXPECT_EQ(GetTID(), getpid());
}
#endif
} // namespace
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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/thread_identity.h"
#if !defined(_WIN32) || defined(__MINGW32__)
#include <pthread.h>
#ifndef __wasi__
// WASI does not provide this header, either way we disable use
// of signals with it below.
#include <signal.h>
#endif
#endif
#include <atomic>
#include <cassert>
#include <memory>
#include "absl/base/attributes.h"
#include "absl/base/call_once.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/spinlock.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if ABSL_THREAD_IDENTITY_MODE != ABSL_THREAD_IDENTITY_MODE_USE_CPP11
namespace {
// Used to co-ordinate one-time creation of our pthread_key
absl::once_flag init_thread_identity_key_once;
pthread_key_t thread_identity_pthread_key;
std::atomic<bool> pthread_key_initialized(false);
void AllocateThreadIdentityKey(ThreadIdentityReclaimerFunction reclaimer) {
pthread_key_create(&thread_identity_pthread_key, reclaimer);
pthread_key_initialized.store(true, std::memory_order_release);
}
} // namespace
#endif
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
// The actual TLS storage for a thread's currently associated ThreadIdentity.
// This is referenced by inline accessors in the header.
// "protected" visibility ensures that if multiple instances of Abseil code
// exist within a process (via dlopen() or similar), references to
// thread_identity_ptr from each instance of the code will refer to
// *different* instances of this ptr.
// Apple platforms have the visibility attribute, but issue a compile warning
// that protected visibility is unsupported.
ABSL_CONST_INIT // Must come before __attribute__((visibility("protected")))
#if ABSL_HAVE_ATTRIBUTE(visibility) && !defined(__APPLE__)
__attribute__((visibility("protected")))
#endif // ABSL_HAVE_ATTRIBUTE(visibility) && !defined(__APPLE__)
#if ABSL_PER_THREAD_TLS
// Prefer __thread to thread_local as benchmarks indicate it is a bit
// faster.
ABSL_PER_THREAD_TLS_KEYWORD ThreadIdentity* thread_identity_ptr = nullptr;
#elif defined(ABSL_HAVE_THREAD_LOCAL)
thread_local ThreadIdentity* thread_identity_ptr = nullptr;
#endif // ABSL_PER_THREAD_TLS
#endif // TLS or CPP11
void SetCurrentThreadIdentity(ThreadIdentity* identity,
ThreadIdentityReclaimerFunction reclaimer) {
assert(CurrentThreadIdentityIfPresent() == nullptr);
// Associate our destructor.
// NOTE: This call to pthread_setspecific is currently the only immovable
// barrier to CurrentThreadIdentity() always being async signal safe.
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
// NOTE: Not async-safe. But can be open-coded.
absl::call_once(init_thread_identity_key_once, AllocateThreadIdentityKey,
reclaimer);
#if defined(__wasi__) || defined(__EMSCRIPTEN__) || defined(__MINGW32__) || \
defined(__hexagon__)
// Emscripten, WASI and MinGW pthread implementations does not support
// signals. See
// https://kripken.github.io/emscripten-site/docs/porting/pthreads.html for
// more information.
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
#else
// We must mask signals around the call to setspecific as with current glibc,
// a concurrent getspecific (needed for GetCurrentThreadIdentityIfPresent())
// may zero our value.
//
// While not officially async-signal safe, getspecific within a signal handler
// is otherwise OK.
sigset_t all_signals;
sigset_t curr_signals;
sigfillset(&all_signals);
pthread_sigmask(SIG_SETMASK, &all_signals, &curr_signals);
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
pthread_sigmask(SIG_SETMASK, &curr_signals, nullptr);
#endif // !__EMSCRIPTEN__ && !__MINGW32__
#elif ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS
// NOTE: Not async-safe. But can be open-coded.
absl::call_once(init_thread_identity_key_once, AllocateThreadIdentityKey,
reclaimer);
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
thread_identity_ptr = identity;
#elif ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
thread_local std::unique_ptr<ThreadIdentity, ThreadIdentityReclaimerFunction>
holder(identity, reclaimer);
thread_identity_ptr = identity;
#else
#error Unimplemented ABSL_THREAD_IDENTITY_MODE
#endif
}
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
// Please see the comment on `CurrentThreadIdentityIfPresent` in
// thread_identity.h. When we cannot expose thread_local variables in
// headers, we opt for the correct-but-slower option of not inlining this
// function.
#ifndef ABSL_INTERNAL_INLINE_CURRENT_THREAD_IDENTITY_IF_PRESENT
ThreadIdentity* CurrentThreadIdentityIfPresent() { return thread_identity_ptr; }
#endif
#endif
void ClearCurrentThreadIdentity() {
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
thread_identity_ptr = nullptr;
#elif ABSL_THREAD_IDENTITY_MODE == \
ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
// pthread_setspecific expected to clear value on destruction
assert(CurrentThreadIdentityIfPresent() == nullptr);
#endif
}
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
ThreadIdentity* CurrentThreadIdentityIfPresent() {
bool initialized = pthread_key_initialized.load(std::memory_order_acquire);
if (!initialized) {
return nullptr;
}
return reinterpret_cast<ThreadIdentity*>(
pthread_getspecific(thread_identity_pthread_key));
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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.
//
// Each active thread has an ThreadIdentity that may represent the thread in
// various level interfaces. ThreadIdentity objects are never deallocated.
// When a thread terminates, its ThreadIdentity object may be reused for a
// thread created later.
#ifndef ABSL_BASE_INTERNAL_THREAD_IDENTITY_H_
#define ABSL_BASE_INTERNAL_THREAD_IDENTITY_H_
#ifndef _WIN32
#include <pthread.h>
// Defines __GOOGLE_GRTE_VERSION__ (via glibc-specific features.h) when
// supported.
#include <unistd.h>
#endif
#include <atomic>
#include <cstdint>
#include "absl/base/config.h"
#include "absl/base/internal/per_thread_tls.h"
#include "absl/base/optimization.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
struct SynchLocksHeld;
struct SynchWaitParams;
namespace base_internal {
class SpinLock;
struct ThreadIdentity;
// Used by the implementation of absl::Mutex and absl::CondVar.
struct PerThreadSynch {
// The internal representation of absl::Mutex and absl::CondVar rely
// on the alignment of PerThreadSynch. Both store the address of the
// PerThreadSynch in the high-order bits of their internal state,
// which means the low kLowZeroBits of the address of PerThreadSynch
// must be zero.
static constexpr int kLowZeroBits = 8;
static constexpr int kAlignment = 1 << kLowZeroBits;
// Returns the associated ThreadIdentity.
// This can be implemented as a cast because we guarantee
// PerThreadSynch is the first element of ThreadIdentity.
ThreadIdentity* thread_identity() {
return reinterpret_cast<ThreadIdentity*>(this);
}
PerThreadSynch* next; // Circular waiter queue; initialized to 0.
PerThreadSynch* skip; // If non-zero, all entries in Mutex queue
// up to and including "skip" have same
// condition as this, and will be woken later
bool may_skip; // if false while on mutex queue, a mutex unlocker
// is using this PerThreadSynch as a terminator. Its
// skip field must not be filled in because the loop
// might then skip over the terminator.
bool wake; // This thread is to be woken from a Mutex.
// If "x" is on a waiter list for a mutex, "x->cond_waiter" is true iff the
// waiter is waiting on the mutex as part of a CV Wait or Mutex Await.
//
// The value of "x->cond_waiter" is meaningless if "x" is not on a
// Mutex waiter list.
bool cond_waiter;
bool maybe_unlocking; // Valid at head of Mutex waiter queue;
// true if UnlockSlow could be searching
// for a waiter to wake. Used for an optimization
// in Enqueue(). true is always a valid value.
// Can be reset to false when the unlocker or any
// writer releases the lock, or a reader fully
// releases the lock. It may not be set to false
// by a reader that decrements the count to
// non-zero. protected by mutex spinlock
bool suppress_fatal_errors; // If true, try to proceed even in the face
// of broken invariants. This is used within
// fatal signal handlers to improve the
// chances of debug logging information being
// output successfully.
int priority; // Priority of thread (updated every so often).
// State values:
// kAvailable: This PerThreadSynch is available.
// kQueued: This PerThreadSynch is unavailable, it's currently queued on a
// Mutex or CondVar waistlist.
//
// Transitions from kQueued to kAvailable require a release
// barrier. This is needed as a waiter may use "state" to
// independently observe that it's no longer queued.
//
// Transitions from kAvailable to kQueued require no barrier, they
// are externally ordered by the Mutex.
enum State { kAvailable, kQueued };
std::atomic<State> state;
// The wait parameters of the current wait. waitp is null if the
// thread is not waiting. Transitions from null to non-null must
// occur before the enqueue commit point (state = kQueued in
// Enqueue() and CondVarEnqueue()). Transitions from non-null to
// null must occur after the wait is finished (state = kAvailable in
// Mutex::Block() and CondVar::WaitCommon()). This field may be
// changed only by the thread that describes this PerThreadSynch. A
// special case is Fer(), which calls Enqueue() on another thread,
// but with an identical SynchWaitParams pointer, thus leaving the
// pointer unchanged.
SynchWaitParams* waitp;
intptr_t readers; // Number of readers in mutex.
// When priority will next be read (cycles).
int64_t next_priority_read_cycles;
// Locks held; used during deadlock detection.
// Allocated in Synch_GetAllLocks() and freed in ReclaimThreadIdentity().
SynchLocksHeld* all_locks;
};
// The instances of this class are allocated in NewThreadIdentity() with an
// alignment of PerThreadSynch::kAlignment and never destroyed. Initialization
// should happen in OneTimeInitThreadIdentity().
//
// Instances may be reused by new threads - fields should be reset in
// ResetThreadIdentityBetweenReuse().
//
// NOTE: The layout of fields in this structure is critical, please do not
// add, remove, or modify the field placements without fully auditing the
// layout.
struct ThreadIdentity {
// Must be the first member. The Mutex implementation requires that
// the PerThreadSynch object associated with each thread is
// PerThreadSynch::kAlignment aligned. We provide this alignment on
// ThreadIdentity itself.
PerThreadSynch per_thread_synch;
// Private: Reserved for absl::synchronization_internal::Waiter.
struct WaiterState {
alignas(void*) char data[256];
} waiter_state;
// Used by PerThreadSem::{Get,Set}ThreadBlockedCounter().
std::atomic<int>* blocked_count_ptr;
// The following variables are mostly read/written just by the
// thread itself. The only exception is that these are read by
// a ticker thread as a hint.
std::atomic<int> ticker; // Tick counter, incremented once per second.
std::atomic<int> wait_start; // Ticker value when thread started waiting.
std::atomic<bool> is_idle; // Has thread become idle yet?
ThreadIdentity* next;
};
// Returns the ThreadIdentity object representing the calling thread; guaranteed
// to be unique for its lifetime. The returned object will remain valid for the
// program's lifetime; although it may be re-assigned to a subsequent thread.
// If one does not exist, return nullptr instead.
//
// Does not malloc(*), and is async-signal safe.
// [*] Technically pthread_setspecific() does malloc on first use; however this
// is handled internally within tcmalloc's initialization already. Note that
// darwin does *not* use tcmalloc, so this can catch you if using MallocHooks
// on Apple platforms. Whatever function is calling your MallocHooks will need
// to watch for recursion on Apple platforms.
//
// New ThreadIdentity objects can be constructed and associated with a thread
// by calling GetOrCreateCurrentThreadIdentity() in per-thread-sem.h.
ThreadIdentity* CurrentThreadIdentityIfPresent();
using ThreadIdentityReclaimerFunction = void (*)(void*);
// Sets the current thread identity to the given value. 'reclaimer' is a
// pointer to the global function for cleaning up instances on thread
// destruction.
void SetCurrentThreadIdentity(ThreadIdentity* identity,
ThreadIdentityReclaimerFunction reclaimer);
// Removes the currently associated ThreadIdentity from the running thread.
// This must be called from inside the ThreadIdentityReclaimerFunction, and only
// from that function.
void ClearCurrentThreadIdentity();
// May be chosen at compile time via: -DABSL_FORCE_THREAD_IDENTITY_MODE=<mode
// index>
#ifdef ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
#error ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC cannot be directly set
#else
#define ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC 0
#endif
#ifdef ABSL_THREAD_IDENTITY_MODE_USE_TLS
#error ABSL_THREAD_IDENTITY_MODE_USE_TLS cannot be directly set
#else
#define ABSL_THREAD_IDENTITY_MODE_USE_TLS 1
#endif
#ifdef ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#error ABSL_THREAD_IDENTITY_MODE_USE_CPP11 cannot be directly set
#else
#define ABSL_THREAD_IDENTITY_MODE_USE_CPP11 2
#endif
#ifdef ABSL_THREAD_IDENTITY_MODE
#error ABSL_THREAD_IDENTITY_MODE cannot be directly set
#elif defined(ABSL_FORCE_THREAD_IDENTITY_MODE)
#define ABSL_THREAD_IDENTITY_MODE ABSL_FORCE_THREAD_IDENTITY_MODE
#elif defined(_WIN32) && !defined(__MINGW32__)
#define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#elif defined(__APPLE__) && defined(ABSL_HAVE_THREAD_LOCAL)
#define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#elif ABSL_PER_THREAD_TLS && defined(__GOOGLE_GRTE_VERSION__) && \
(__GOOGLE_GRTE_VERSION__ >= 20140228L)
// Support for async-safe TLS was specifically added in GRTEv4. It's not
// present in the upstream eglibc.
// Note: Current default for production systems.
#define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_TLS
#else
#define ABSL_THREAD_IDENTITY_MODE \
ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
#endif
#if ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS || \
ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_CPP11
#if ABSL_PER_THREAD_TLS
ABSL_CONST_INIT extern ABSL_PER_THREAD_TLS_KEYWORD ThreadIdentity*
thread_identity_ptr;
#elif defined(ABSL_HAVE_THREAD_LOCAL)
ABSL_CONST_INIT extern thread_local ThreadIdentity* thread_identity_ptr;
#else
#error Thread-local storage not detected on this platform
#endif
// thread_local variables cannot be in headers exposed by DLLs or in certain
// build configurations on Apple platforms. However, it is important for
// performance reasons in general that `CurrentThreadIdentityIfPresent` be
// inlined. In the other cases we opt to have the function not be inlined. Note
// that `CurrentThreadIdentityIfPresent` is declared above so we can exclude
// this entire inline definition.
#if !defined(__APPLE__) && !defined(ABSL_BUILD_DLL) && \
!defined(ABSL_CONSUME_DLL)
#define ABSL_INTERNAL_INLINE_CURRENT_THREAD_IDENTITY_IF_PRESENT 1
#endif
#ifdef ABSL_INTERNAL_INLINE_CURRENT_THREAD_IDENTITY_IF_PRESENT
inline ThreadIdentity* CurrentThreadIdentityIfPresent() {
return thread_identity_ptr;
}
#endif
#elif ABSL_THREAD_IDENTITY_MODE != \
ABSL_THREAD_IDENTITY_MODE_USE_POSIX_SETSPECIFIC
#error Unknown ABSL_THREAD_IDENTITY_MODE
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_THREAD_IDENTITY_H_

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// 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 "benchmark/benchmark.h"
#include "absl/base/internal/thread_identity.h"
#include "absl/synchronization/internal/create_thread_identity.h"
#include "absl/synchronization/internal/per_thread_sem.h"
namespace {
void BM_SafeCurrentThreadIdentity(benchmark::State& state) {
for (auto _ : state) {
benchmark::DoNotOptimize(
absl::synchronization_internal::GetOrCreateCurrentThreadIdentity());
}
}
BENCHMARK(BM_SafeCurrentThreadIdentity);
void BM_UnsafeCurrentThreadIdentity(benchmark::State& state) {
for (auto _ : state) {
benchmark::DoNotOptimize(
absl::base_internal::CurrentThreadIdentityIfPresent());
}
}
BENCHMARK(BM_UnsafeCurrentThreadIdentity);
} // namespace

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// 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/thread_identity.h"
#include <thread> // NOLINT(build/c++11)
#include <vector>
#include "gtest/gtest.h"
#include "absl/base/attributes.h"
#include "absl/base/internal/spinlock.h"
#include "absl/base/macros.h"
#include "absl/base/thread_annotations.h"
#include "absl/synchronization/internal/per_thread_sem.h"
#include "absl/synchronization/mutex.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
ABSL_CONST_INIT static absl::base_internal::SpinLock map_lock(
absl::kConstInit, base_internal::SCHEDULE_KERNEL_ONLY);
ABSL_CONST_INIT static int num_identities_reused ABSL_GUARDED_BY(map_lock);
static const void* const kCheckNoIdentity = reinterpret_cast<void*>(1);
static void TestThreadIdentityCurrent(const void* assert_no_identity) {
ThreadIdentity* identity;
// We have to test this conditionally, because if the test framework relies
// on Abseil, then some previous action may have already allocated an
// identity.
if (assert_no_identity == kCheckNoIdentity) {
identity = CurrentThreadIdentityIfPresent();
EXPECT_TRUE(identity == nullptr);
}
identity = synchronization_internal::GetOrCreateCurrentThreadIdentity();
EXPECT_TRUE(identity != nullptr);
ThreadIdentity* identity_no_init;
identity_no_init = CurrentThreadIdentityIfPresent();
EXPECT_TRUE(identity == identity_no_init);
// Check that per_thread_synch is correctly aligned.
EXPECT_EQ(0, reinterpret_cast<intptr_t>(&identity->per_thread_synch) %
PerThreadSynch::kAlignment);
EXPECT_EQ(identity, identity->per_thread_synch.thread_identity());
absl::base_internal::SpinLockHolder l(&map_lock);
num_identities_reused++;
}
TEST(ThreadIdentityTest, BasicIdentityWorks) {
// This tests for the main() thread.
TestThreadIdentityCurrent(nullptr);
}
TEST(ThreadIdentityTest, BasicIdentityWorksThreaded) {
// Now try the same basic test with multiple threads being created and
// destroyed. This makes sure that:
// - New threads are created without a ThreadIdentity.
// - We re-allocate ThreadIdentity objects from the free-list.
// - If a thread implementation chooses to recycle threads, that
// correct re-initialization occurs.
static const int kNumLoops = 3;
static const int kNumThreads = 32;
for (int iter = 0; iter < kNumLoops; iter++) {
std::vector<std::thread> threads;
for (int i = 0; i < kNumThreads; ++i) {
threads.push_back(
std::thread(TestThreadIdentityCurrent, kCheckNoIdentity));
}
for (auto& thread : threads) {
thread.join();
}
}
// We should have recycled ThreadIdentity objects above; while (external)
// library threads allocating their own identities may preclude some
// reuse, we should have sufficient repetitions to exclude this.
absl::base_internal::SpinLockHolder l(&map_lock);
EXPECT_LT(kNumThreads, num_identities_reused);
}
TEST(ThreadIdentityTest, ReusedThreadIdentityMutexTest) {
// This test repeatedly creates and joins a series of threads, each of
// which acquires and releases shared Mutex locks. This verifies
// Mutex operations work correctly under a reused
// ThreadIdentity. Note that the most likely failure mode of this
// test is a crash or deadlock.
static const int kNumLoops = 10;
static const int kNumThreads = 12;
static const int kNumMutexes = 3;
static const int kNumLockLoops = 5;
Mutex mutexes[kNumMutexes];
for (int iter = 0; iter < kNumLoops; ++iter) {
std::vector<std::thread> threads;
for (int thread = 0; thread < kNumThreads; ++thread) {
threads.push_back(std::thread([&]() {
for (int l = 0; l < kNumLockLoops; ++l) {
for (int m = 0; m < kNumMutexes; ++m) {
MutexLock lock(&mutexes[m]);
}
}
}));
}
for (auto& thread : threads) {
thread.join();
}
}
}
} // namespace
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// 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/throw_delegate.h"
#include <cstdlib>
#include <functional>
#include <new>
#include <stdexcept>
#include "absl/base/config.h"
#include "absl/base/internal/raw_logging.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// NOTE: The exception types, like `std::logic_error`, do not exist on all
// platforms. (For example, the Android NDK does not have them.)
// Therefore, their use must be guarded by `#ifdef` or equivalent.
void ThrowStdLogicError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::logic_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdLogicError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::logic_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdInvalidArgument(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::invalid_argument(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdInvalidArgument(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::invalid_argument(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdDomainError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::domain_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdDomainError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::domain_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdLengthError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::length_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdLengthError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::length_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdOutOfRange(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::out_of_range(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdOutOfRange(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::out_of_range(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdRuntimeError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::runtime_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdRuntimeError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::runtime_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdRangeError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::range_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdRangeError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::range_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdOverflowError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::overflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdOverflowError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::overflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdUnderflowError(const std::string& what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::underflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg.c_str());
std::abort();
#endif
}
void ThrowStdUnderflowError(const char* what_arg) {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::underflow_error(what_arg);
#else
ABSL_RAW_LOG(FATAL, "%s", what_arg);
std::abort();
#endif
}
void ThrowStdBadFunctionCall() {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::bad_function_call();
#else
std::abort();
#endif
}
void ThrowStdBadAlloc() {
#ifdef ABSL_HAVE_EXCEPTIONS
throw std::bad_alloc();
#else
std::abort();
#endif
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// 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.
//
#ifndef ABSL_BASE_INTERNAL_THROW_DELEGATE_H_
#define ABSL_BASE_INTERNAL_THROW_DELEGATE_H_
#include <string>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Helper functions that allow throwing exceptions consistently from anywhere.
// The main use case is for header-based libraries (eg templates), as they will
// be built by many different targets with their own compiler options.
// In particular, this will allow a safe way to throw exceptions even if the
// caller is compiled with -fno-exceptions. This is intended for implementing
// things like map<>::at(), which the standard documents as throwing an
// exception on error.
//
// Using other techniques like #if tricks could lead to ODR violations.
//
// You shouldn't use it unless you're writing code that you know will be built
// both with and without exceptions and you need to conform to an interface
// that uses exceptions.
[[noreturn]] void ThrowStdLogicError(const std::string& what_arg);
[[noreturn]] void ThrowStdLogicError(const char* what_arg);
[[noreturn]] void ThrowStdInvalidArgument(const std::string& what_arg);
[[noreturn]] void ThrowStdInvalidArgument(const char* what_arg);
[[noreturn]] void ThrowStdDomainError(const std::string& what_arg);
[[noreturn]] void ThrowStdDomainError(const char* what_arg);
[[noreturn]] void ThrowStdLengthError(const std::string& what_arg);
[[noreturn]] void ThrowStdLengthError(const char* what_arg);
[[noreturn]] void ThrowStdOutOfRange(const std::string& what_arg);
[[noreturn]] void ThrowStdOutOfRange(const char* what_arg);
[[noreturn]] void ThrowStdRuntimeError(const std::string& what_arg);
[[noreturn]] void ThrowStdRuntimeError(const char* what_arg);
[[noreturn]] void ThrowStdRangeError(const std::string& what_arg);
[[noreturn]] void ThrowStdRangeError(const char* what_arg);
[[noreturn]] void ThrowStdOverflowError(const std::string& what_arg);
[[noreturn]] void ThrowStdOverflowError(const char* what_arg);
[[noreturn]] void ThrowStdUnderflowError(const std::string& what_arg);
[[noreturn]] void ThrowStdUnderflowError(const char* what_arg);
[[noreturn]] void ThrowStdBadFunctionCall();
[[noreturn]] void ThrowStdBadAlloc();
// ThrowStdBadArrayNewLength() cannot be consistently supported because
// std::bad_array_new_length is missing in libstdc++ until 4.9.0.
// https://gcc.gnu.org/onlinedocs/gcc-4.8.3/libstdc++/api/a01379_source.html
// https://gcc.gnu.org/onlinedocs/gcc-4.9.0/libstdc++/api/a01327_source.html
// libcxx (as of 3.2) and msvc (as of 2015) both have it.
// [[noreturn]] void ThrowStdBadArrayNewLength();
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_THROW_DELEGATE_H_

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// Copyright 2024 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/tracing.h"
#include "absl/base/attributes.h"
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
extern "C" {
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceWait)(
const void*, ObjectKind) {}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceContinue)(
const void*, ObjectKind) {}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceSignal)(
const void*, ObjectKind) {}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceObserved)(
const void*, ObjectKind) {}
} // extern "C"
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl

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// Copyright 2024 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_TRACING_H_
#define ABSL_BASE_INTERNAL_TRACING_H_
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Well known Abseil object types that have causality.
enum class ObjectKind { kUnknown, kBlockingCounter, kNotification };
// `TraceWait` and `TraceContinue` record the start and end of a potentially
// blocking wait operation on `object`. `object` typically represents a higher
// level synchronization object such as `absl::Notification`.
void TraceWait(const void* object, ObjectKind kind);
void TraceContinue(const void* object, ObjectKind kind);
// `TraceSignal` records a signal on `object`.
void TraceSignal(const void* object, ObjectKind kind);
// `TraceObserved` records the non-blocking observation of a signaled object.
void TraceObserved(const void* object, ObjectKind kind);
// ---------------------------------------------------------------------------
// Weak implementation detail:
//
// We define the weak API as extern "C": in some build configurations we pass
// `--detect-odr-violations` to the gold linker. This causes it to flag weak
// symbol overrides as ODR violations. Because ODR only applies to C++ and not
// C, `--detect-odr-violations` ignores symbols not mangled with C++ names.
// By changing our extension points to be extern "C", we dodge this check.
// ---------------------------------------------------------------------------
extern "C" {
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceWait)(const void* object,
ObjectKind kind);
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceContinue)(const void* object,
ObjectKind kind);
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceSignal)(const void* object,
ObjectKind kind);
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceObserved)(const void* object,
ObjectKind kind);
} // extern "C"
inline void TraceWait(const void* object, ObjectKind kind) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceWait)(object, kind);
}
inline void TraceContinue(const void* object, ObjectKind kind) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceContinue)(object, kind);
}
inline void TraceSignal(const void* object, ObjectKind kind) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceSignal)(object, kind);
}
inline void TraceObserved(const void* object, ObjectKind kind) {
ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceObserved)(object, kind);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_TRACING_H_

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// Copyright 2024 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 <tuple>
#include <vector>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/tracing.h"
#if ABSL_HAVE_ATTRIBUTE_WEAK
namespace {
using ::testing::ElementsAre;
using ::absl::base_internal::ObjectKind;
enum Function { kWait, kContinue, kSignal, kObserved };
using Record = std::tuple<Function, const void*, ObjectKind>;
thread_local std::vector<Record>* tls_records = nullptr;
} // namespace
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Strong extern "C" implementation.
extern "C" {
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceWait)(const void* object,
ObjectKind kind) {
if (tls_records != nullptr) {
tls_records->push_back({kWait, object, kind});
}
}
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceContinue)(const void* object,
ObjectKind kind) {
if (tls_records != nullptr) {
tls_records->push_back({kContinue, object, kind});
}
}
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceSignal)(const void* object,
ObjectKind kind) {
if (tls_records != nullptr) {
tls_records->push_back({kSignal, object, kind});
}
}
void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceObserved)(const void* object,
ObjectKind kind) {
if (tls_records != nullptr) {
tls_records->push_back({kObserved, object, kind});
}
}
} // extern "C"
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
namespace {
TEST(TracingInternal, InvokesStrongFunctionWithNullptr) {
std::vector<Record> records;
tls_records = &records;
auto kind = absl::base_internal::ObjectKind::kUnknown;
absl::base_internal::TraceWait(nullptr, kind);
absl::base_internal::TraceContinue(nullptr, kind);
absl::base_internal::TraceSignal(nullptr, kind);
absl::base_internal::TraceObserved(nullptr, kind);
tls_records = nullptr;
EXPECT_THAT(records, ElementsAre(Record{kWait, nullptr, kind},
Record{kContinue, nullptr, kind},
Record{kSignal, nullptr, kind},
Record{kObserved, nullptr, kind}));
}
TEST(TracingInternal, InvokesStrongFunctionWithObjectAddress) {
int object = 0;
std::vector<Record> records;
tls_records = &records;
auto kind = absl::base_internal::ObjectKind::kUnknown;
absl::base_internal::TraceWait(&object, kind);
absl::base_internal::TraceContinue(&object, kind);
absl::base_internal::TraceSignal(&object, kind);
absl::base_internal::TraceObserved(&object, kind);
tls_records = nullptr;
EXPECT_THAT(records, ElementsAre(Record{kWait, &object, kind},
Record{kContinue, &object, kind},
Record{kSignal, &object, kind},
Record{kObserved, &object, kind}));
}
} // namespace
#endif // ABSL_HAVE_ATTRIBUTE_WEAK

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// Copyright 2024 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 "gtest/gtest.h"
#include "absl/base/internal/tracing.h"
namespace {
TEST(TracingInternal, HasDefaultImplementation) {
auto kind = absl::base_internal::ObjectKind::kUnknown;
absl::base_internal::TraceWait(nullptr, kind);
absl::base_internal::TraceContinue(nullptr, kind);
absl::base_internal::TraceSignal(nullptr, kind);
absl::base_internal::TraceObserved(nullptr, kind);
int object = 0;
absl::base_internal::TraceWait(&object, kind);
absl::base_internal::TraceContinue(&object, kind);
absl::base_internal::TraceSignal(&object, kind);
absl::base_internal::TraceObserved(&object, kind);
}
} // namespace

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// 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.
//
// This file is intended solely for spinlock.h.
// It provides ThreadSanitizer annotations for custom mutexes.
// See <sanitizer/tsan_interface.h> for meaning of these annotations.
#ifndef ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_
#define ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_
#include "absl/base/config.h"
// ABSL_INTERNAL_HAVE_TSAN_INTERFACE
// Macro intended only for internal use.
//
// Checks whether LLVM Thread Sanitizer interfaces are available.
// First made available in LLVM 5.0 (Sep 2017).
#ifdef ABSL_INTERNAL_HAVE_TSAN_INTERFACE
#error "ABSL_INTERNAL_HAVE_TSAN_INTERFACE cannot be directly set."
#endif
#if defined(ABSL_HAVE_THREAD_SANITIZER) && defined(__has_include)
#if __has_include(<sanitizer/tsan_interface.h>)
#define ABSL_INTERNAL_HAVE_TSAN_INTERFACE 1
#endif
#endif
#ifdef ABSL_INTERNAL_HAVE_TSAN_INTERFACE
#include <sanitizer/tsan_interface.h>
#define ABSL_TSAN_MUTEX_CREATE __tsan_mutex_create
#define ABSL_TSAN_MUTEX_DESTROY __tsan_mutex_destroy
#define ABSL_TSAN_MUTEX_PRE_LOCK __tsan_mutex_pre_lock
#define ABSL_TSAN_MUTEX_POST_LOCK __tsan_mutex_post_lock
#define ABSL_TSAN_MUTEX_PRE_UNLOCK __tsan_mutex_pre_unlock
#define ABSL_TSAN_MUTEX_POST_UNLOCK __tsan_mutex_post_unlock
#define ABSL_TSAN_MUTEX_PRE_SIGNAL __tsan_mutex_pre_signal
#define ABSL_TSAN_MUTEX_POST_SIGNAL __tsan_mutex_post_signal
#define ABSL_TSAN_MUTEX_PRE_DIVERT __tsan_mutex_pre_divert
#define ABSL_TSAN_MUTEX_POST_DIVERT __tsan_mutex_post_divert
#else
#define ABSL_TSAN_MUTEX_CREATE(...)
#define ABSL_TSAN_MUTEX_DESTROY(...)
#define ABSL_TSAN_MUTEX_PRE_LOCK(...)
#define ABSL_TSAN_MUTEX_POST_LOCK(...)
#define ABSL_TSAN_MUTEX_PRE_UNLOCK(...)
#define ABSL_TSAN_MUTEX_POST_UNLOCK(...)
#define ABSL_TSAN_MUTEX_PRE_SIGNAL(...)
#define ABSL_TSAN_MUTEX_POST_SIGNAL(...)
#define ABSL_TSAN_MUTEX_PRE_DIVERT(...)
#define ABSL_TSAN_MUTEX_POST_DIVERT(...)
#endif
#endif // ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_

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//
// 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.
//
#ifndef ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_
#define ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_
#include <string.h>
#include <cstdint>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/nullability.h"
// unaligned APIs
// Portable handling of unaligned loads, stores, and copies.
// The unaligned API is C++ only. The declarations use C++ features
// (namespaces, inline) which are absent or incompatible in C.
#if defined(__cplusplus)
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
inline uint16_t UnalignedLoad16(absl::Nonnull<const void *> p) {
uint16_t t;
memcpy(&t, p, sizeof t);
return t;
}
inline uint32_t UnalignedLoad32(absl::Nonnull<const void *> p) {
uint32_t t;
memcpy(&t, p, sizeof t);
return t;
}
inline uint64_t UnalignedLoad64(absl::Nonnull<const void *> p) {
uint64_t t;
memcpy(&t, p, sizeof t);
return t;
}
inline void UnalignedStore16(absl::Nonnull<void *> p, uint16_t v) {
memcpy(p, &v, sizeof v);
}
inline void UnalignedStore32(absl::Nonnull<void *> p, uint32_t v) {
memcpy(p, &v, sizeof v);
}
inline void UnalignedStore64(absl::Nonnull<void *> p, uint64_t v) {
memcpy(p, &v, sizeof v);
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#define ABSL_INTERNAL_UNALIGNED_LOAD16(_p) \
(absl::base_internal::UnalignedLoad16(_p))
#define ABSL_INTERNAL_UNALIGNED_LOAD32(_p) \
(absl::base_internal::UnalignedLoad32(_p))
#define ABSL_INTERNAL_UNALIGNED_LOAD64(_p) \
(absl::base_internal::UnalignedLoad64(_p))
#define ABSL_INTERNAL_UNALIGNED_STORE16(_p, _val) \
(absl::base_internal::UnalignedStore16(_p, _val))
#define ABSL_INTERNAL_UNALIGNED_STORE32(_p, _val) \
(absl::base_internal::UnalignedStore32(_p, _val))
#define ABSL_INTERNAL_UNALIGNED_STORE64(_p, _val) \
(absl::base_internal::UnalignedStore64(_p, _val))
#endif // defined(__cplusplus), end of unaligned API
#endif // ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_

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// Copyright 2020 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 "gtest/gtest.h"
#include "absl/base/optimization.h"
#include "absl/strings/string_view.h"
// This test by itself does not do anything fancy, but it serves as binary I can
// query in shell test.
namespace {
template <class T>
void DoNotOptimize(const T& var) {
#ifdef __GNUC__
asm volatile("" : "+m"(const_cast<T&>(var)));
#else
std::cout << (void*)&var;
#endif
}
int very_long_int_variable_name ABSL_INTERNAL_UNIQUE_SMALL_NAME() = 0;
char very_long_str_variable_name[] ABSL_INTERNAL_UNIQUE_SMALL_NAME() = "abc";
TEST(UniqueSmallName, NonAutomaticVar) {
EXPECT_EQ(very_long_int_variable_name, 0);
EXPECT_EQ(absl::string_view(very_long_str_variable_name), "abc");
}
int VeryLongFreeFunctionName() ABSL_INTERNAL_UNIQUE_SMALL_NAME();
TEST(UniqueSmallName, FreeFunction) {
DoNotOptimize(&VeryLongFreeFunctionName);
EXPECT_EQ(VeryLongFreeFunctionName(), 456);
}
int VeryLongFreeFunctionName() { return 456; }
struct VeryLongStructName {
explicit VeryLongStructName(int i);
int VeryLongMethodName() ABSL_INTERNAL_UNIQUE_SMALL_NAME();
static int VeryLongStaticMethodName() ABSL_INTERNAL_UNIQUE_SMALL_NAME();
private:
int fld;
};
TEST(UniqueSmallName, Struct) {
VeryLongStructName var(10);
DoNotOptimize(var);
DoNotOptimize(&VeryLongStructName::VeryLongMethodName);
DoNotOptimize(&VeryLongStructName::VeryLongStaticMethodName);
EXPECT_EQ(var.VeryLongMethodName(), 10);
EXPECT_EQ(VeryLongStructName::VeryLongStaticMethodName(), 123);
}
VeryLongStructName::VeryLongStructName(int i) : fld(i) {}
int VeryLongStructName::VeryLongMethodName() { return fld; }
int VeryLongStructName::VeryLongStaticMethodName() { return 123; }
} // namespace

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// 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/unscaledcycleclock.h"
#if ABSL_USE_UNSCALED_CYCLECLOCK
#if defined(_WIN32)
#include <intrin.h>
#endif
#if defined(__powerpc__) || defined(__ppc__)
#ifdef __GLIBC__
#include <sys/platform/ppc.h>
#elif defined(__FreeBSD__)
// clang-format off
// This order does actually matter =(.
#include <sys/types.h>
#include <sys/sysctl.h>
// clang-format on
#include "absl/base/call_once.h"
#endif
#endif
#include "absl/base/internal/sysinfo.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
#if defined(__i386__)
int64_t UnscaledCycleClock::Now() {
int64_t ret;
__asm__ volatile("rdtsc" : "=A"(ret));
return ret;
}
double UnscaledCycleClock::Frequency() {
return base_internal::NominalCPUFrequency();
}
#elif defined(__x86_64__)
double UnscaledCycleClock::Frequency() {
return base_internal::NominalCPUFrequency();
}
#elif defined(__powerpc__) || defined(__ppc__)
int64_t UnscaledCycleClock::Now() {
#ifdef __GLIBC__
return __ppc_get_timebase();
#else
#ifdef __powerpc64__
int64_t tbr;
asm volatile("mfspr %0, 268" : "=r"(tbr));
return tbr;
#else
int32_t tbu, tbl, tmp;
asm volatile(
"mftbu %[hi32]\n"
"mftb %[lo32]\n"
"mftbu %[tmp]\n"
"cmpw %[tmp],%[hi32]\n"
"bne $-16\n" // Retry on failure.
: [hi32] "=r"(tbu), [lo32] "=r"(tbl), [tmp] "=r"(tmp));
return (static_cast<int64_t>(tbu) << 32) | tbl;
#endif
#endif
}
double UnscaledCycleClock::Frequency() {
#ifdef __GLIBC__
return __ppc_get_timebase_freq();
#elif defined(_AIX)
// This is the same constant value as returned by
// __ppc_get_timebase_freq().
return static_cast<double>(512000000);
#elif defined(__FreeBSD__)
static once_flag init_timebase_frequency_once;
static double timebase_frequency = 0.0;
base_internal::LowLevelCallOnce(&init_timebase_frequency_once, [&]() {
size_t length = sizeof(timebase_frequency);
sysctlbyname("kern.timecounter.tc.timebase.frequency", &timebase_frequency,
&length, nullptr, 0);
});
return timebase_frequency;
#else
#error Must implement UnscaledCycleClock::Frequency()
#endif
}
#elif defined(__aarch64__)
double UnscaledCycleClock::Frequency() {
uint64_t aarch64_timer_frequency;
asm volatile("mrs %0, cntfrq_el0" : "=r"(aarch64_timer_frequency));
return aarch64_timer_frequency;
}
#elif defined(_M_IX86) || defined(_M_X64)
#pragma intrinsic(__rdtsc)
int64_t UnscaledCycleClock::Now() { return __rdtsc(); }
double UnscaledCycleClock::Frequency() {
return base_internal::NominalCPUFrequency();
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_USE_UNSCALED_CYCLECLOCK

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// 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.
//
// UnscaledCycleClock
// An UnscaledCycleClock yields the value and frequency of a cycle counter
// that increments at a rate that is approximately constant.
// This class is for internal use only, you should consider using CycleClock
// instead.
//
// Notes:
// The cycle counter frequency is not necessarily the core clock frequency.
// That is, CycleCounter cycles are not necessarily "CPU cycles".
//
// An arbitrary offset may have been added to the counter at power on.
//
// On some platforms, the rate and offset of the counter may differ
// slightly when read from different CPUs of a multiprocessor. Usually,
// we try to ensure that the operating system adjusts values periodically
// so that values agree approximately. If you need stronger guarantees,
// consider using alternate interfaces.
//
// The CPU is not required to maintain the ordering of a cycle counter read
// with respect to surrounding instructions.
#ifndef ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_
#define ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_
#include <cstdint>
#if defined(__APPLE__)
#include <TargetConditionals.h>
#endif
#include "absl/base/config.h"
#include "absl/base/internal/unscaledcycleclock_config.h"
#if ABSL_USE_UNSCALED_CYCLECLOCK
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace time_internal {
class UnscaledCycleClockWrapperForGetCurrentTime;
} // namespace time_internal
namespace base_internal {
class CycleClock;
class UnscaledCycleClockWrapperForInitializeFrequency;
class UnscaledCycleClock {
private:
UnscaledCycleClock() = delete;
// Return the value of a cycle counter that counts at a rate that is
// approximately constant.
static int64_t Now();
// Return the how much UnscaledCycleClock::Now() increases per second.
// This is not necessarily the core CPU clock frequency.
// It may be the nominal value report by the kernel, rather than a measured
// value.
static double Frequency();
// Allowed users
friend class base_internal::CycleClock;
friend class time_internal::UnscaledCycleClockWrapperForGetCurrentTime;
friend class base_internal::UnscaledCycleClockWrapperForInitializeFrequency;
};
#if defined(__x86_64__)
inline int64_t UnscaledCycleClock::Now() {
uint64_t low, high;
__asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
return static_cast<int64_t>((high << 32) | low);
}
#elif defined(__aarch64__)
// System timer of ARMv8 runs at a different frequency than the CPU's.
// The frequency is fixed, typically in the range 1-50MHz. It can be
// read at CNTFRQ special register. We assume the OS has set up
// the virtual timer properly.
inline int64_t UnscaledCycleClock::Now() {
int64_t virtual_timer_value;
asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value));
return virtual_timer_value;
}
#endif
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_USE_UNSCALED_CYCLECLOCK
#endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_

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// Copyright 2022 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_UNSCALEDCYCLECLOCK_CONFIG_H_
#define ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_
#if defined(__APPLE__)
#include <TargetConditionals.h>
#endif
// The following platforms have an implementation of a hardware counter.
#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
defined(__powerpc__) || defined(__ppc__) || defined(_M_IX86) || \
(defined(_M_X64) && !defined(_M_ARM64EC))
#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 1
#else
#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 0
#endif
// The following platforms often disable access to the hardware
// counter (through a sandbox) even if the underlying hardware has a
// usable counter. The CycleTimer interface also requires a *scaled*
// CycleClock that runs at atleast 1 MHz. We've found some Android
// ARM64 devices where this is not the case, so we disable it by
// default on Android ARM64.
#if defined(__native_client__) || (defined(__APPLE__)) || \
(defined(__ANDROID__) && defined(__aarch64__))
#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 0
#else
#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 1
#endif
// UnscaledCycleClock is an optional internal feature.
// Use "#if ABSL_USE_UNSCALED_CYCLECLOCK" to test for its presence.
// Can be overridden at compile-time via -DABSL_USE_UNSCALED_CYCLECLOCK=0|1
#if !defined(ABSL_USE_UNSCALED_CYCLECLOCK)
#define ABSL_USE_UNSCALED_CYCLECLOCK \
(ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION && \
ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT)
#endif
#if ABSL_USE_UNSCALED_CYCLECLOCK
// This macro can be used to test if UnscaledCycleClock::Frequency()
// is NominalCPUFrequency() on a particular platform.
#if (defined(__i386__) || defined(__x86_64__) || defined(_M_IX86) || \
defined(_M_X64))
#define ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
#endif
#endif
#endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_