diff options
Diffstat (limited to 'third_party/abseil-cpp/absl/base/internal')
64 files changed, 9063 insertions, 0 deletions
diff --git a/third_party/abseil-cpp/absl/base/internal/atomic_hook.h b/third_party/abseil-cpp/absl/base/internal/atomic_hook.h new file mode 100644 index 0000000000..ae21cd7fe5 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/atomic_hook.h @@ -0,0 +1,200 @@ +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/atomic_hook_test.cc b/third_party/abseil-cpp/absl/base/internal/atomic_hook_test.cc new file mode 100644 index 0000000000..e577a8fd93 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/atomic_hook_test.cc @@ -0,0 +1,97 @@ +// 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 diff --git a/third_party/abseil-cpp/absl/base/internal/atomic_hook_test_helper.cc b/third_party/abseil-cpp/absl/base/internal/atomic_hook_test_helper.cc new file mode 100644 index 0000000000..537d47cd2d --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/atomic_hook_test_helper.cc @@ -0,0 +1,32 @@ +// 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 diff --git a/third_party/abseil-cpp/absl/base/internal/atomic_hook_test_helper.h b/third_party/abseil-cpp/absl/base/internal/atomic_hook_test_helper.h new file mode 100644 index 0000000000..3e72b4977d --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/atomic_hook_test_helper.h @@ -0,0 +1,34 @@ +// 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_ATOMIC_HOOK_TEST_HELPER_H_ +#define ABSL_BASE_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_ATOMIC_HOOK_TEST_HELPER_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/bits.h b/third_party/abseil-cpp/absl/base/internal/bits.h new file mode 100644 index 0000000000..8b03453c18 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/bits.h @@ -0,0 +1,218 @@ +// 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_BITS_H_ +#define ABSL_BASE_INTERNAL_BITS_H_ + +// This file contains bitwise ops which are implementation details of various +// absl libraries. + +#include <cstdint> + +#include "absl/base/config.h" + +// Clang on Windows has __builtin_clzll; otherwise we need to use the +// windows intrinsic functions. +#if defined(_MSC_VER) +#include <intrin.h> +#if defined(_M_X64) +#pragma intrinsic(_BitScanReverse64) +#pragma intrinsic(_BitScanForward64) +#endif +#pragma intrinsic(_BitScanReverse) +#pragma intrinsic(_BitScanForward) +#endif + +#include "absl/base/attributes.h" + +#if defined(_MSC_VER) +// We can achieve something similar to attribute((always_inline)) with MSVC by +// using the __forceinline keyword, however this is not perfect. MSVC is +// much less aggressive about inlining, and even with the __forceinline keyword. +#define ABSL_BASE_INTERNAL_FORCEINLINE __forceinline +#else +// Use default attribute inline. +#define ABSL_BASE_INTERNAL_FORCEINLINE inline ABSL_ATTRIBUTE_ALWAYS_INLINE +#endif + + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros64Slow(uint64_t n) { + int zeroes = 60; + if (n >> 32) { + zeroes -= 32; + n >>= 32; + } + if (n >> 16) { + zeroes -= 16; + n >>= 16; + } + if (n >> 8) { + zeroes -= 8; + n >>= 8; + } + if (n >> 4) { + zeroes -= 4; + n >>= 4; + } + return "\4\3\2\2\1\1\1\1\0\0\0\0\0\0\0"[n] + zeroes; +} + +ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros64(uint64_t n) { +#if defined(_MSC_VER) && defined(_M_X64) + // MSVC does not have __buitin_clzll. Use _BitScanReverse64. + unsigned long result = 0; // NOLINT(runtime/int) + if (_BitScanReverse64(&result, n)) { + return 63 - result; + } + return 64; +#elif defined(_MSC_VER) + // MSVC does not have __buitin_clzll. Compose two calls to _BitScanReverse + unsigned long result = 0; // NOLINT(runtime/int) + if ((n >> 32) && _BitScanReverse(&result, n >> 32)) { + return 31 - result; + } + if (_BitScanReverse(&result, n)) { + return 63 - result; + } + return 64; +#elif defined(__GNUC__) + // Use __builtin_clzll, which uses the following instructions: + // x86: bsr + // ARM64: clz + // PPC: cntlzd + static_assert(sizeof(unsigned long long) == sizeof(n), // NOLINT(runtime/int) + "__builtin_clzll does not take 64-bit arg"); + + // Handle 0 as a special case because __builtin_clzll(0) is undefined. + if (n == 0) { + return 64; + } + return __builtin_clzll(n); +#else + return CountLeadingZeros64Slow(n); +#endif +} + +ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros32Slow(uint64_t n) { + int zeroes = 28; + if (n >> 16) { + zeroes -= 16; + n >>= 16; + } + if (n >> 8) { + zeroes -= 8; + n >>= 8; + } + if (n >> 4) { + zeroes -= 4; + n >>= 4; + } + return "\4\3\2\2\1\1\1\1\0\0\0\0\0\0\0"[n] + zeroes; +} + +ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros32(uint32_t n) { +#if defined(_MSC_VER) + unsigned long result = 0; // NOLINT(runtime/int) + if (_BitScanReverse(&result, n)) { + return 31 - result; + } + return 32; +#elif defined(__GNUC__) + // Use __builtin_clz, which uses the following instructions: + // x86: bsr + // ARM64: clz + // PPC: cntlzd + static_assert(sizeof(int) == sizeof(n), + "__builtin_clz does not take 32-bit arg"); + + // Handle 0 as a special case because __builtin_clz(0) is undefined. + if (n == 0) { + return 32; + } + return __builtin_clz(n); +#else + return CountLeadingZeros32Slow(n); +#endif +} + +ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero64Slow(uint64_t n) { + int c = 63; + n &= ~n + 1; + if (n & 0x00000000FFFFFFFF) c -= 32; + if (n & 0x0000FFFF0000FFFF) c -= 16; + if (n & 0x00FF00FF00FF00FF) c -= 8; + if (n & 0x0F0F0F0F0F0F0F0F) c -= 4; + if (n & 0x3333333333333333) c -= 2; + if (n & 0x5555555555555555) c -= 1; + return c; +} + +ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero64(uint64_t n) { +#if defined(_MSC_VER) && defined(_M_X64) + unsigned long result = 0; // NOLINT(runtime/int) + _BitScanForward64(&result, n); + return result; +#elif defined(_MSC_VER) + unsigned long result = 0; // NOLINT(runtime/int) + if (static_cast<uint32_t>(n) == 0) { + _BitScanForward(&result, n >> 32); + return result + 32; + } + _BitScanForward(&result, n); + return result; +#elif defined(__GNUC__) + static_assert(sizeof(unsigned long long) == sizeof(n), // NOLINT(runtime/int) + "__builtin_ctzll does not take 64-bit arg"); + return __builtin_ctzll(n); +#else + return CountTrailingZerosNonZero64Slow(n); +#endif +} + +ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero32Slow(uint32_t n) { + int c = 31; + n &= ~n + 1; + if (n & 0x0000FFFF) c -= 16; + if (n & 0x00FF00FF) c -= 8; + if (n & 0x0F0F0F0F) c -= 4; + if (n & 0x33333333) c -= 2; + if (n & 0x55555555) c -= 1; + return c; +} + +ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero32(uint32_t n) { +#if defined(_MSC_VER) + unsigned long result = 0; // NOLINT(runtime/int) + _BitScanForward(&result, n); + return result; +#elif defined(__GNUC__) + static_assert(sizeof(int) == sizeof(n), + "__builtin_ctz does not take 32-bit arg"); + return __builtin_ctz(n); +#else + return CountTrailingZerosNonZero32Slow(n); +#endif +} + +#undef ABSL_BASE_INTERNAL_FORCEINLINE + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_BITS_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/bits_test.cc b/third_party/abseil-cpp/absl/base/internal/bits_test.cc new file mode 100644 index 0000000000..7855fa6297 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/bits_test.cc @@ -0,0 +1,97 @@ +// 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/bits.h" + +#include "gtest/gtest.h" + +namespace { + +int CLZ64(uint64_t n) { + int fast = absl::base_internal::CountLeadingZeros64(n); + int slow = absl::base_internal::CountLeadingZeros64Slow(n); + EXPECT_EQ(fast, slow) << n; + return fast; +} + +TEST(BitsTest, CountLeadingZeros64) { + EXPECT_EQ(64, CLZ64(uint64_t{})); + EXPECT_EQ(0, CLZ64(~uint64_t{})); + + for (int index = 0; index < 64; index++) { + uint64_t x = static_cast<uint64_t>(1) << index; + const auto cnt = 63 - index; + ASSERT_EQ(cnt, CLZ64(x)) << index; + ASSERT_EQ(cnt, CLZ64(x + x - 1)) << index; + } +} + +int CLZ32(uint32_t n) { + int fast = absl::base_internal::CountLeadingZeros32(n); + int slow = absl::base_internal::CountLeadingZeros32Slow(n); + EXPECT_EQ(fast, slow) << n; + return fast; +} + +TEST(BitsTest, CountLeadingZeros32) { + EXPECT_EQ(32, CLZ32(uint32_t{})); + EXPECT_EQ(0, CLZ32(~uint32_t{})); + + for (int index = 0; index < 32; index++) { + uint32_t x = static_cast<uint32_t>(1) << index; + const auto cnt = 31 - index; + ASSERT_EQ(cnt, CLZ32(x)) << index; + ASSERT_EQ(cnt, CLZ32(x + x - 1)) << index; + ASSERT_EQ(CLZ64(x), CLZ32(x) + 32); + } +} + +int CTZ64(uint64_t n) { + int fast = absl::base_internal::CountTrailingZerosNonZero64(n); + int slow = absl::base_internal::CountTrailingZerosNonZero64Slow(n); + EXPECT_EQ(fast, slow) << n; + return fast; +} + +TEST(BitsTest, CountTrailingZerosNonZero64) { + EXPECT_EQ(0, CTZ64(~uint64_t{})); + + for (int index = 0; index < 64; index++) { + uint64_t x = static_cast<uint64_t>(1) << index; + const auto cnt = index; + ASSERT_EQ(cnt, CTZ64(x)) << index; + ASSERT_EQ(cnt, CTZ64(~(x - 1))) << index; + } +} + +int CTZ32(uint32_t n) { + int fast = absl::base_internal::CountTrailingZerosNonZero32(n); + int slow = absl::base_internal::CountTrailingZerosNonZero32Slow(n); + EXPECT_EQ(fast, slow) << n; + return fast; +} + +TEST(BitsTest, CountTrailingZerosNonZero32) { + EXPECT_EQ(0, CTZ32(~uint32_t{})); + + for (int index = 0; index < 32; index++) { + uint32_t x = static_cast<uint32_t>(1) << index; + const auto cnt = index; + ASSERT_EQ(cnt, CTZ32(x)) << index; + ASSERT_EQ(cnt, CTZ32(~(x - 1))) << index; + } +} + + +} // namespace diff --git a/third_party/abseil-cpp/absl/base/internal/cmake_thread_test.cc b/third_party/abseil-cpp/absl/base/internal/cmake_thread_test.cc new file mode 100644 index 0000000000..f70bb24eb7 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/cmake_thread_test.cc @@ -0,0 +1,22 @@ +// 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; +} diff --git a/third_party/abseil-cpp/absl/base/internal/cycleclock.cc b/third_party/abseil-cpp/absl/base/internal/cycleclock.cc new file mode 100644 index 0000000000..0e65005b89 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/cycleclock.cc @@ -0,0 +1,107 @@ +// 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/internal/unscaledcycleclock.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +#if ABSL_USE_UNSCALED_CYCLECLOCK + +namespace { + +#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. +static constexpr int32_t kShift = 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. +static constexpr int32_t kShift = 0; +#endif +#else +// In debug mode use a different shift to discourage depending on a +// particular shift value. +static constexpr int32_t kShift = 2; +#endif + +static constexpr double kFrequencyScale = 1.0 / (1 << kShift); +static std::atomic<CycleClockSourceFunc> cycle_clock_source; + +CycleClockSourceFunc LoadCycleClockSource() { + // 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; + } + // 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); +} + +} // namespace + +int64_t CycleClock::Now() { + auto fn = LoadCycleClockSource(); + if (fn == nullptr) { + return base_internal::UnscaledCycleClock::Now() >> kShift; + } + return fn() >> kShift; +} + +double CycleClock::Frequency() { + return kFrequencyScale * base_internal::UnscaledCycleClock::Frequency(); +} + +void CycleClockSource::Register(CycleClockSourceFunc source) { + // Corresponds to the load(std::memory_order_acquire) in LoadCycleClockSource. + cycle_clock_source.store(source, std::memory_order_release); +} + +#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 diff --git a/third_party/abseil-cpp/absl/base/internal/cycleclock.h b/third_party/abseil-cpp/absl/base/internal/cycleclock.h new file mode 100644 index 0000000000..a18b584445 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/cycleclock.h @@ -0,0 +1,94 @@ +// +// 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 <cstdint> + +#include "absl/base/config.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +// ----------------------------------------------------------------------------- +// 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: + CycleClock() = delete; // no instances + CycleClock(const CycleClock&) = delete; + CycleClock& operator=(const CycleClock&) = delete; +}; + +using CycleClockSourceFunc = int64_t (*)(); + +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); +}; + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_CYCLECLOCK_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/direct_mmap.h b/third_party/abseil-cpp/absl/base/internal/direct_mmap.h new file mode 100644 index 0000000000..5618867ba0 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/direct_mmap.h @@ -0,0 +1,161 @@ +// 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" + +#if 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. +#ifdef __BIONIC__ +// 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__ +#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__ + +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, + off64_t offset) noexcept { +#if defined(__i386__) || defined(__ARM_ARCH_3__) || defined(__ARM_EABI__) || \ + (defined(__mips__) && _MIPS_SIM == _MIPS_SIM_ABI32) || \ + (defined(__PPC__) && !defined(__PPC64__)) || \ + (defined(__s390__) && !defined(__s390x__)) + // 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, offset / pagesize); +#else + return reinterpret_cast<void*>( + syscall(SYS_mmap2, start, length, prot, flags, fd, + static_cast<off_t>(offset / pagesize))); +#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_ diff --git a/third_party/abseil-cpp/absl/base/internal/endian.h b/third_party/abseil-cpp/absl/base/internal/endian.h new file mode 100644 index 0000000000..9677530e8d --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/endian.h @@ -0,0 +1,266 @@ +// 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_ + +// The following guarantees declaration of the byte swap functions +#ifdef _MSC_VER +#include <stdlib.h> // NOLINT(build/include) +#elif defined(__FreeBSD__) +#include <sys/endian.h> +#elif defined(__GLIBC__) +#include <byteswap.h> // IWYU pragma: export +#endif + +#include <cstdint> +#include "absl/base/config.h" +#include "absl/base/internal/unaligned_access.h" +#include "absl/base/port.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN + +// Use compiler byte-swapping intrinsics if they are available. 32-bit +// and 64-bit versions are available in Clang and GCC as of GCC 4.3.0. +// The 16-bit version is available in Clang and GCC only as of GCC 4.8.0. +// For simplicity, we enable them all only for GCC 4.8.0 or later. +#if defined(__clang__) || \ + (defined(__GNUC__) && \ + ((__GNUC__ == 4 && __GNUC_MINOR__ >= 8) || __GNUC__ >= 5)) +inline uint64_t gbswap_64(uint64_t host_int) { + return __builtin_bswap64(host_int); +} +inline uint32_t gbswap_32(uint32_t host_int) { + return __builtin_bswap32(host_int); +} +inline uint16_t gbswap_16(uint16_t host_int) { + return __builtin_bswap16(host_int); +} + +#elif defined(_MSC_VER) +inline uint64_t gbswap_64(uint64_t host_int) { + return _byteswap_uint64(host_int); +} +inline uint32_t gbswap_32(uint32_t host_int) { + return _byteswap_ulong(host_int); +} +inline uint16_t gbswap_16(uint16_t host_int) { + return _byteswap_ushort(host_int); +} + +#else +inline uint64_t gbswap_64(uint64_t host_int) { +#if defined(__GNUC__) && defined(__x86_64__) && !defined(__APPLE__) + // Adapted from /usr/include/byteswap.h. Not available on Mac. + if (__builtin_constant_p(host_int)) { + return __bswap_constant_64(host_int); + } else { + uint64_t result; + __asm__("bswap %0" : "=r"(result) : "0"(host_int)); + return result; + } +#elif defined(__GLIBC__) + return bswap_64(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 // bswap_64 +} + +inline uint32_t gbswap_32(uint32_t host_int) { +#if defined(__GLIBC__) + return bswap_32(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 defined(__GLIBC__) + return bswap_16(host_int); +#else + return (((host_int & uint16_t{0xFF}) << 8) | + ((host_int & uint16_t{0xFF00}) >> 8)); +#endif +} + +#endif // intrinsics available + +#ifdef ABSL_IS_LITTLE_ENDIAN + +// Definitions for ntohl etc. that don't require us to include +// netinet/in.h. We wrap gbswap_32 and gbswap_16 in functions rather +// than just #defining them because in debug mode, gcc doesn't +// correctly handle the (rather involved) definitions of bswap_32. +// gcc guarantees that inline functions are as fast as macros, so +// this isn't a performance hit. +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 + +// These definitions are simpler on big-endian machines +// These are functions instead of macros to avoid self-assignment warnings +// on calls such as "i = ghtnol(i);". This also provides type checking. +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 */ + +// Functions to do unaligned loads and stores in little-endian order. +inline uint16_t Load16(const void *p) { + return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p)); +} + +inline void Store16(void *p, uint16_t v) { + ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v)); +} + +inline uint32_t Load32(const void *p) { + return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p)); +} + +inline void Store32(void *p, uint32_t v) { + ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v)); +} + +inline uint64_t Load64(const void *p) { + return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p)); +} + +inline void Store64(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 */ + +// Functions to do unaligned loads and stores in big-endian order. +inline uint16_t Load16(const void *p) { + return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p)); +} + +inline void Store16(void *p, uint16_t v) { + ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v)); +} + +inline uint32_t Load32(const void *p) { + return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p)); +} + +inline void Store32(void *p, uint32_t v) { + ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v)); +} + +inline uint64_t Load64(const void *p) { + return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p)); +} + +inline void Store64(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_ diff --git a/third_party/abseil-cpp/absl/base/internal/endian_test.cc b/third_party/abseil-cpp/absl/base/internal/endian_test.cc new file mode 100644 index 0000000000..aa6b849690 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/endian_test.cc @@ -0,0 +1,265 @@ +// 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 + +template<typename T> +std::vector<T> GenerateAllValuesForType() { + std::vector<T> result; + T next = std::numeric_limits<T>::min(); + while (true) { + result.push_back(next); + if (next == std::numeric_limits<T>::max()) { + return result; + } + ++next; + } +} + +template<typename T> +std::vector<T> GenerateRandomIntegers(size_t numValuesToTest) { + std::vector<T> result; + std::mt19937_64 rng(kRandomSeed); + for (size_t i = 0; i < numValuesToTest; ++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(GenerateAllValuesForType<uint16_t>(), &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 diff --git a/third_party/abseil-cpp/absl/base/internal/errno_saver.h b/third_party/abseil-cpp/absl/base/internal/errno_saver.h new file mode 100644 index 0000000000..251de510fc --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/errno_saver.h @@ -0,0 +1,43 @@ +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/errno_saver_test.cc b/third_party/abseil-cpp/absl/base/internal/errno_saver_test.cc new file mode 100644 index 0000000000..b845e2dd1a --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/errno_saver_test.cc @@ -0,0 +1,44 @@ +// 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" + +namespace { +using ::testing::Eq; + +struct ErrnoPrinter { + int no; +}; +std::ostream &operator<<(std::ostream &os, ErrnoPrinter ep) { + return os << 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 diff --git a/third_party/abseil-cpp/absl/base/internal/exception_safety_testing.cc b/third_party/abseil-cpp/absl/base/internal/exception_safety_testing.cc new file mode 100644 index 0000000000..6ccac41864 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/exception_safety_testing.cc @@ -0,0 +1,79 @@ +// 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 diff --git a/third_party/abseil-cpp/absl/base/internal/exception_safety_testing.h b/third_party/abseil-cpp/absl/base/internal/exception_safety_testing.h new file mode 100644 index 0000000000..6ba89d05df --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/exception_safety_testing.h @@ -0,0 +1,1101 @@ +// 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. + +// Utilities for testing exception-safety + +#ifndef ABSL_BASE_INTERNAL_EXCEPTION_SAFETY_TESTING_H_ +#define ABSL_BASE_INTERNAL_EXCEPTION_SAFETY_TESTING_H_ + +#include "absl/base/config.h" + +#ifdef ABSL_HAVE_EXCEPTIONS + +#include <cstddef> +#include <cstdint> +#include <functional> +#include <initializer_list> +#include <iosfwd> +#include <string> +#include <tuple> +#include <unordered_map> + +#include "gtest/gtest.h" +#include "absl/base/internal/pretty_function.h" +#include "absl/memory/memory.h" +#include "absl/meta/type_traits.h" +#include "absl/strings/string_view.h" +#include "absl/strings/substitute.h" +#include "absl/utility/utility.h" + +namespace testing { + +enum class TypeSpec; +enum class AllocSpec; + +constexpr TypeSpec operator|(TypeSpec a, TypeSpec b) { + using T = absl::underlying_type_t<TypeSpec>; + return static_cast<TypeSpec>(static_cast<T>(a) | static_cast<T>(b)); +} + +constexpr TypeSpec operator&(TypeSpec a, TypeSpec b) { + using T = absl::underlying_type_t<TypeSpec>; + return static_cast<TypeSpec>(static_cast<T>(a) & static_cast<T>(b)); +} + +constexpr AllocSpec operator|(AllocSpec a, AllocSpec b) { + using T = absl::underlying_type_t<AllocSpec>; + return static_cast<AllocSpec>(static_cast<T>(a) | static_cast<T>(b)); +} + +constexpr AllocSpec operator&(AllocSpec a, AllocSpec b) { + using T = absl::underlying_type_t<AllocSpec>; + return static_cast<AllocSpec>(static_cast<T>(a) & static_cast<T>(b)); +} + +namespace exceptions_internal { + +std::string GetSpecString(TypeSpec); +std::string GetSpecString(AllocSpec); + +struct NoThrowTag {}; +struct StrongGuaranteeTagType {}; + +// A simple exception class. We throw this so that test code can catch +// exceptions specifically thrown by ThrowingValue. +class TestException { + public: + explicit TestException(absl::string_view msg) : msg_(msg) {} + virtual ~TestException() {} + virtual const char* what() const noexcept { return msg_.c_str(); } + + private: + std::string msg_; +}; + +// TestBadAllocException exists because allocation functions must throw an +// exception which can be caught by a handler of std::bad_alloc. We use a child +// class of std::bad_alloc so we can customise the error message, and also +// derive from TestException so we don't accidentally end up catching an actual +// bad_alloc exception in TestExceptionSafety. +class TestBadAllocException : public std::bad_alloc, public TestException { + public: + explicit TestBadAllocException(absl::string_view msg) : TestException(msg) {} + using TestException::what; +}; + +extern int countdown; + +// Allows the countdown variable to be set manually (defaulting to the initial +// value of 0) +inline void SetCountdown(int i = 0) { countdown = i; } +// Sets the countdown to the terminal value -1 +inline void UnsetCountdown() { SetCountdown(-1); } + +void MaybeThrow(absl::string_view msg, bool throw_bad_alloc = false); + +testing::AssertionResult FailureMessage(const TestException& e, + int countdown) noexcept; + +struct TrackedAddress { + bool is_alive; + std::string description; +}; + +// Inspects the constructions and destructions of anything inheriting from +// TrackedObject. This allows us to safely "leak" TrackedObjects, as +// ConstructorTracker will destroy everything left over in its destructor. +class ConstructorTracker { + public: + explicit ConstructorTracker(int count) : countdown_(count) { + assert(current_tracker_instance_ == nullptr); + current_tracker_instance_ = this; + } + + ~ConstructorTracker() { + assert(current_tracker_instance_ == this); + current_tracker_instance_ = nullptr; + + for (auto& it : address_map_) { + void* address = it.first; + TrackedAddress& tracked_address = it.second; + if (tracked_address.is_alive) { + ADD_FAILURE() << ErrorMessage(address, tracked_address.description, + countdown_, "Object was not destroyed."); + } + } + } + + static void ObjectConstructed(void* address, std::string description) { + if (!CurrentlyTracking()) return; + + TrackedAddress& tracked_address = + current_tracker_instance_->address_map_[address]; + if (tracked_address.is_alive) { + ADD_FAILURE() << ErrorMessage( + address, tracked_address.description, + current_tracker_instance_->countdown_, + "Object was re-constructed. Current object was constructed by " + + description); + } + tracked_address = {true, std::move(description)}; + } + + static void ObjectDestructed(void* address) { + if (!CurrentlyTracking()) return; + + auto it = current_tracker_instance_->address_map_.find(address); + // Not tracked. Ignore. + if (it == current_tracker_instance_->address_map_.end()) return; + + TrackedAddress& tracked_address = it->second; + if (!tracked_address.is_alive) { + ADD_FAILURE() << ErrorMessage(address, tracked_address.description, + current_tracker_instance_->countdown_, + "Object was re-destroyed."); + } + tracked_address.is_alive = false; + } + + private: + static bool CurrentlyTracking() { + return current_tracker_instance_ != nullptr; + } + + static std::string ErrorMessage(void* address, + const std::string& address_description, + int countdown, + const std::string& error_description) { + return absl::Substitute( + "With coundtown at $0:\n" + " $1\n" + " Object originally constructed by $2\n" + " Object address: $3\n", + countdown, error_description, address_description, address); + } + + std::unordered_map<void*, TrackedAddress> address_map_; + int countdown_; + + static ConstructorTracker* current_tracker_instance_; +}; + +class TrackedObject { + public: + TrackedObject(const TrackedObject&) = delete; + TrackedObject(TrackedObject&&) = delete; + + protected: + explicit TrackedObject(std::string description) { + ConstructorTracker::ObjectConstructed(this, std::move(description)); + } + + ~TrackedObject() noexcept { ConstructorTracker::ObjectDestructed(this); } +}; +} // namespace exceptions_internal + +extern exceptions_internal::NoThrowTag nothrow_ctor; + +extern exceptions_internal::StrongGuaranteeTagType strong_guarantee; + +// A test class which is convertible to bool. The conversion can be +// instrumented to throw at a controlled time. +class ThrowingBool { + public: + ThrowingBool(bool b) noexcept : b_(b) {} // NOLINT(runtime/explicit) + operator bool() const { // NOLINT + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return b_; + } + + private: + bool b_; +}; + +/* + * Configuration enum for the ThrowingValue type that defines behavior for the + * lifetime of the instance. Use testing::nothrow_ctor to prevent the integer + * constructor from throwing. + * + * kEverythingThrows: Every operation can throw an exception + * kNoThrowCopy: Copy construction and copy assignment will not throw + * kNoThrowMove: Move construction and move assignment will not throw + * kNoThrowNew: Overloaded operators new and new[] will not throw + */ +enum class TypeSpec { + kEverythingThrows = 0, + kNoThrowCopy = 1, + kNoThrowMove = 1 << 1, + kNoThrowNew = 1 << 2, +}; + +/* + * A testing class instrumented to throw an exception at a controlled time. + * + * ThrowingValue implements a slightly relaxed version of the Regular concept -- + * that is it's a value type with the expected semantics. It also implements + * arithmetic operations. It doesn't implement member and pointer operators + * like operator-> or operator[]. + * + * ThrowingValue can be instrumented to have certain operations be noexcept by + * using compile-time bitfield template arguments. That is, to make an + * ThrowingValue which has noexcept move construction/assignment and noexcept + * copy construction/assignment, use the following: + * ThrowingValue<testing::kNoThrowMove | testing::kNoThrowCopy> my_thrwr{val}; + */ +template <TypeSpec Spec = TypeSpec::kEverythingThrows> +class ThrowingValue : private exceptions_internal::TrackedObject { + static constexpr bool IsSpecified(TypeSpec spec) { + return static_cast<bool>(Spec & spec); + } + + static constexpr int kDefaultValue = 0; + static constexpr int kBadValue = 938550620; + + public: + ThrowingValue() : TrackedObject(GetInstanceString(kDefaultValue)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ = kDefaultValue; + } + + ThrowingValue(const ThrowingValue& other) noexcept( + IsSpecified(TypeSpec::kNoThrowCopy)) + : TrackedObject(GetInstanceString(other.dummy_)) { + if (!IsSpecified(TypeSpec::kNoThrowCopy)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + } + dummy_ = other.dummy_; + } + + ThrowingValue(ThrowingValue&& other) noexcept( + IsSpecified(TypeSpec::kNoThrowMove)) + : TrackedObject(GetInstanceString(other.dummy_)) { + if (!IsSpecified(TypeSpec::kNoThrowMove)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + } + dummy_ = other.dummy_; + } + + explicit ThrowingValue(int i) : TrackedObject(GetInstanceString(i)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ = i; + } + + ThrowingValue(int i, exceptions_internal::NoThrowTag) noexcept + : TrackedObject(GetInstanceString(i)), dummy_(i) {} + + // absl expects nothrow destructors + ~ThrowingValue() noexcept = default; + + ThrowingValue& operator=(const ThrowingValue& other) noexcept( + IsSpecified(TypeSpec::kNoThrowCopy)) { + dummy_ = kBadValue; + if (!IsSpecified(TypeSpec::kNoThrowCopy)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + } + dummy_ = other.dummy_; + return *this; + } + + ThrowingValue& operator=(ThrowingValue&& other) noexcept( + IsSpecified(TypeSpec::kNoThrowMove)) { + dummy_ = kBadValue; + if (!IsSpecified(TypeSpec::kNoThrowMove)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + } + dummy_ = other.dummy_; + return *this; + } + + // Arithmetic Operators + ThrowingValue operator+(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ + other.dummy_, nothrow_ctor); + } + + ThrowingValue operator+() const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_, nothrow_ctor); + } + + ThrowingValue operator-(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ - other.dummy_, nothrow_ctor); + } + + ThrowingValue operator-() const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(-dummy_, nothrow_ctor); + } + + ThrowingValue& operator++() { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + ++dummy_; + return *this; + } + + ThrowingValue operator++(int) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + auto out = ThrowingValue(dummy_, nothrow_ctor); + ++dummy_; + return out; + } + + ThrowingValue& operator--() { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + --dummy_; + return *this; + } + + ThrowingValue operator--(int) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + auto out = ThrowingValue(dummy_, nothrow_ctor); + --dummy_; + return out; + } + + ThrowingValue operator*(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ * other.dummy_, nothrow_ctor); + } + + ThrowingValue operator/(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ / other.dummy_, nothrow_ctor); + } + + ThrowingValue operator%(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ % other.dummy_, nothrow_ctor); + } + + ThrowingValue operator<<(int shift) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ << shift, nothrow_ctor); + } + + ThrowingValue operator>>(int shift) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ >> shift, nothrow_ctor); + } + + // Comparison Operators + // NOTE: We use `ThrowingBool` instead of `bool` because most STL + // types/containers requires T to be convertible to bool. + friend ThrowingBool operator==(const ThrowingValue& a, + const ThrowingValue& b) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return a.dummy_ == b.dummy_; + } + friend ThrowingBool operator!=(const ThrowingValue& a, + const ThrowingValue& b) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return a.dummy_ != b.dummy_; + } + friend ThrowingBool operator<(const ThrowingValue& a, + const ThrowingValue& b) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return a.dummy_ < b.dummy_; + } + friend ThrowingBool operator<=(const ThrowingValue& a, + const ThrowingValue& b) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return a.dummy_ <= b.dummy_; + } + friend ThrowingBool operator>(const ThrowingValue& a, + const ThrowingValue& b) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return a.dummy_ > b.dummy_; + } + friend ThrowingBool operator>=(const ThrowingValue& a, + const ThrowingValue& b) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return a.dummy_ >= b.dummy_; + } + + // Logical Operators + ThrowingBool operator!() const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return !dummy_; + } + + ThrowingBool operator&&(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return dummy_ && other.dummy_; + } + + ThrowingBool operator||(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return dummy_ || other.dummy_; + } + + // Bitwise Logical Operators + ThrowingValue operator~() const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(~dummy_, nothrow_ctor); + } + + ThrowingValue operator&(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ & other.dummy_, nothrow_ctor); + } + + ThrowingValue operator|(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ | other.dummy_, nothrow_ctor); + } + + ThrowingValue operator^(const ThrowingValue& other) const { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return ThrowingValue(dummy_ ^ other.dummy_, nothrow_ctor); + } + + // Compound Assignment operators + ThrowingValue& operator+=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ += other.dummy_; + return *this; + } + + ThrowingValue& operator-=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ -= other.dummy_; + return *this; + } + + ThrowingValue& operator*=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ *= other.dummy_; + return *this; + } + + ThrowingValue& operator/=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ /= other.dummy_; + return *this; + } + + ThrowingValue& operator%=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ %= other.dummy_; + return *this; + } + + ThrowingValue& operator&=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ &= other.dummy_; + return *this; + } + + ThrowingValue& operator|=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ |= other.dummy_; + return *this; + } + + ThrowingValue& operator^=(const ThrowingValue& other) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ ^= other.dummy_; + return *this; + } + + ThrowingValue& operator<<=(int shift) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ <<= shift; + return *this; + } + + ThrowingValue& operator>>=(int shift) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ >>= shift; + return *this; + } + + // Pointer operators + void operator&() const = delete; // NOLINT(runtime/operator) + + // Stream operators + friend std::ostream& operator<<(std::ostream& os, const ThrowingValue& tv) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return os << GetInstanceString(tv.dummy_); + } + + friend std::istream& operator>>(std::istream& is, const ThrowingValue&) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + return is; + } + + // Memory management operators + // Args.. allows us to overload regular and placement new in one shot + template <typename... Args> + static void* operator new(size_t s, Args&&... args) noexcept( + IsSpecified(TypeSpec::kNoThrowNew)) { + if (!IsSpecified(TypeSpec::kNoThrowNew)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION, true); + } + return ::operator new(s, std::forward<Args>(args)...); + } + + template <typename... Args> + static void* operator new[](size_t s, Args&&... args) noexcept( + IsSpecified(TypeSpec::kNoThrowNew)) { + if (!IsSpecified(TypeSpec::kNoThrowNew)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION, true); + } + return ::operator new[](s, std::forward<Args>(args)...); + } + + // Abseil doesn't support throwing overloaded operator delete. These are + // provided so a throwing operator-new can clean up after itself. + // + // We provide both regular and templated operator delete because if only the + // templated version is provided as we did with operator new, the compiler has + // no way of knowing which overload of operator delete to call. See + // https://en.cppreference.com/w/cpp/memory/new/operator_delete and + // https://en.cppreference.com/w/cpp/language/delete for the gory details. + void operator delete(void* p) noexcept { ::operator delete(p); } + + template <typename... Args> + void operator delete(void* p, Args&&... args) noexcept { + ::operator delete(p, std::forward<Args>(args)...); + } + + void operator delete[](void* p) noexcept { return ::operator delete[](p); } + + template <typename... Args> + void operator delete[](void* p, Args&&... args) noexcept { + return ::operator delete[](p, std::forward<Args>(args)...); + } + + // Non-standard access to the actual contained value. No need for this to + // throw. + int& Get() noexcept { return dummy_; } + const int& Get() const noexcept { return dummy_; } + + private: + static std::string GetInstanceString(int dummy) { + return absl::StrCat("ThrowingValue<", + exceptions_internal::GetSpecString(Spec), ">(", dummy, + ")"); + } + + int dummy_; +}; +// While not having to do with exceptions, explicitly delete comma operator, to +// make sure we don't use it on user-supplied types. +template <TypeSpec Spec, typename T> +void operator,(const ThrowingValue<Spec>&, T&&) = delete; +template <TypeSpec Spec, typename T> +void operator,(T&&, const ThrowingValue<Spec>&) = delete; + +/* + * Configuration enum for the ThrowingAllocator type that defines behavior for + * the lifetime of the instance. + * + * kEverythingThrows: Calls to the member functions may throw + * kNoThrowAllocate: Calls to the member functions will not throw + */ +enum class AllocSpec { + kEverythingThrows = 0, + kNoThrowAllocate = 1, +}; + +/* + * An allocator type which is instrumented to throw at a controlled time, or not + * to throw, using AllocSpec. The supported settings are the default of every + * function which is allowed to throw in a conforming allocator possibly + * throwing, or nothing throws, in line with the ABSL_ALLOCATOR_THROWS + * configuration macro. + */ +template <typename T, AllocSpec Spec = AllocSpec::kEverythingThrows> +class ThrowingAllocator : private exceptions_internal::TrackedObject { + static constexpr bool IsSpecified(AllocSpec spec) { + return static_cast<bool>(Spec & spec); + } + + public: + using pointer = T*; + using const_pointer = const T*; + using reference = T&; + using const_reference = const T&; + using void_pointer = void*; + using const_void_pointer = const void*; + using value_type = T; + using size_type = size_t; + using difference_type = ptrdiff_t; + + using is_nothrow = + std::integral_constant<bool, Spec == AllocSpec::kNoThrowAllocate>; + using propagate_on_container_copy_assignment = std::true_type; + using propagate_on_container_move_assignment = std::true_type; + using propagate_on_container_swap = std::true_type; + using is_always_equal = std::false_type; + + ThrowingAllocator() : TrackedObject(GetInstanceString(next_id_)) { + exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION); + dummy_ = std::make_shared<const int>(next_id_++); + } + + template <typename U> + ThrowingAllocator(const ThrowingAllocator<U, Spec>& other) noexcept // NOLINT + : TrackedObject(GetInstanceString(*other.State())), + dummy_(other.State()) {} + + // According to C++11 standard [17.6.3.5], Table 28, the move/copy ctors of + // allocator shall not exit via an exception, thus they are marked noexcept. + ThrowingAllocator(const ThrowingAllocator& other) noexcept + : TrackedObject(GetInstanceString(*other.State())), + dummy_(other.State()) {} + + template <typename U> + ThrowingAllocator(ThrowingAllocator<U, Spec>&& other) noexcept // NOLINT + : TrackedObject(GetInstanceString(*other.State())), + dummy_(std::move(other.State())) {} + + ThrowingAllocator(ThrowingAllocator&& other) noexcept + : TrackedObject(GetInstanceString(*other.State())), + dummy_(std::move(other.State())) {} + + ~ThrowingAllocator() noexcept = default; + + ThrowingAllocator& operator=(const ThrowingAllocator& other) noexcept { + dummy_ = other.State(); + return *this; + } + + template <typename U> + ThrowingAllocator& operator=( + const ThrowingAllocator<U, Spec>& other) noexcept { + dummy_ = other.State(); + return *this; + } + + template <typename U> + ThrowingAllocator& operator=(ThrowingAllocator<U, Spec>&& other) noexcept { + dummy_ = std::move(other.State()); + return *this; + } + + template <typename U> + struct rebind { + using other = ThrowingAllocator<U, Spec>; + }; + + pointer allocate(size_type n) noexcept( + IsSpecified(AllocSpec::kNoThrowAllocate)) { + ReadStateAndMaybeThrow(ABSL_PRETTY_FUNCTION); + return static_cast<pointer>(::operator new(n * sizeof(T))); + } + + pointer allocate(size_type n, const_void_pointer) noexcept( + IsSpecified(AllocSpec::kNoThrowAllocate)) { + return allocate(n); + } + + void deallocate(pointer ptr, size_type) noexcept { + ReadState(); + ::operator delete(static_cast<void*>(ptr)); + } + + template <typename U, typename... Args> + void construct(U* ptr, Args&&... args) noexcept( + IsSpecified(AllocSpec::kNoThrowAllocate)) { + ReadStateAndMaybeThrow(ABSL_PRETTY_FUNCTION); + ::new (static_cast<void*>(ptr)) U(std::forward<Args>(args)...); + } + + template <typename U> + void destroy(U* p) noexcept { + ReadState(); + p->~U(); + } + + size_type max_size() const noexcept { + return (std::numeric_limits<difference_type>::max)() / sizeof(value_type); + } + + ThrowingAllocator select_on_container_copy_construction() noexcept( + IsSpecified(AllocSpec::kNoThrowAllocate)) { + auto& out = *this; + ReadStateAndMaybeThrow(ABSL_PRETTY_FUNCTION); + return out; + } + + template <typename U> + bool operator==(const ThrowingAllocator<U, Spec>& other) const noexcept { + return dummy_ == other.dummy_; + } + + template <typename U> + bool operator!=(const ThrowingAllocator<U, Spec>& other) const noexcept { + return dummy_ != other.dummy_; + } + + template <typename, AllocSpec> + friend class ThrowingAllocator; + + private: + static std::string GetInstanceString(int dummy) { + return absl::StrCat("ThrowingAllocator<", + exceptions_internal::GetSpecString(Spec), ">(", dummy, + ")"); + } + + const std::shared_ptr<const int>& State() const { return dummy_; } + std::shared_ptr<const int>& State() { return dummy_; } + + void ReadState() { + // we know that this will never be true, but the compiler doesn't, so this + // should safely force a read of the value. + if (*dummy_ < 0) std::abort(); + } + + void ReadStateAndMaybeThrow(absl::string_view msg) const { + if (!IsSpecified(AllocSpec::kNoThrowAllocate)) { + exceptions_internal::MaybeThrow( + absl::Substitute("Allocator id $0 threw from $1", *dummy_, msg)); + } + } + + static int next_id_; + std::shared_ptr<const int> dummy_; +}; + +template <typename T, AllocSpec Spec> +int ThrowingAllocator<T, Spec>::next_id_ = 0; + +// Tests for resource leaks by attempting to construct a T using args repeatedly +// until successful, using the countdown method. Side effects can then be +// tested for resource leaks. +template <typename T, typename... Args> +void TestThrowingCtor(Args&&... args) { + struct Cleanup { + ~Cleanup() { exceptions_internal::UnsetCountdown(); } + } c; + for (int count = 0;; ++count) { + exceptions_internal::ConstructorTracker ct(count); + exceptions_internal::SetCountdown(count); + try { + T temp(std::forward<Args>(args)...); + static_cast<void>(temp); + break; + } catch (const exceptions_internal::TestException&) { + } + } +} + +// Tests the nothrow guarantee of the provided nullary operation. If the an +// exception is thrown, the result will be AssertionFailure(). Otherwise, it +// will be AssertionSuccess(). +template <typename Operation> +testing::AssertionResult TestNothrowOp(const Operation& operation) { + struct Cleanup { + Cleanup() { exceptions_internal::SetCountdown(); } + ~Cleanup() { exceptions_internal::UnsetCountdown(); } + } c; + try { + operation(); + return testing::AssertionSuccess(); + } catch (const exceptions_internal::TestException&) { + return testing::AssertionFailure() + << "TestException thrown during call to operation() when nothrow " + "guarantee was expected."; + } catch (...) { + return testing::AssertionFailure() + << "Unknown exception thrown during call to operation() when " + "nothrow guarantee was expected."; + } +} + +namespace exceptions_internal { + +// Dummy struct for ExceptionSafetyTestBuilder<> partial state. +struct UninitializedT {}; + +template <typename T> +class DefaultFactory { + public: + explicit DefaultFactory(const T& t) : t_(t) {} + std::unique_ptr<T> operator()() const { return absl::make_unique<T>(t_); } + + private: + T t_; +}; + +template <size_t LazyContractsCount, typename LazyFactory, + typename LazyOperation> +using EnableIfTestable = typename absl::enable_if_t< + LazyContractsCount != 0 && + !std::is_same<LazyFactory, UninitializedT>::value && + !std::is_same<LazyOperation, UninitializedT>::value>; + +template <typename Factory = UninitializedT, + typename Operation = UninitializedT, typename... Contracts> +class ExceptionSafetyTestBuilder; + +} // namespace exceptions_internal + +/* + * Constructs an empty ExceptionSafetyTestBuilder. All + * ExceptionSafetyTestBuilder objects are immutable and all With[thing] mutation + * methods return new instances of ExceptionSafetyTestBuilder. + * + * In order to test a T for exception safety, a factory for that T, a testable + * operation, and at least one contract callback returning an assertion + * result must be applied using the respective methods. + */ +exceptions_internal::ExceptionSafetyTestBuilder<> MakeExceptionSafetyTester(); + +namespace exceptions_internal { +template <typename T> +struct IsUniquePtr : std::false_type {}; + +template <typename T, typename D> +struct IsUniquePtr<std::unique_ptr<T, D>> : std::true_type {}; + +template <typename Factory> +struct FactoryPtrTypeHelper { + using type = decltype(std::declval<const Factory&>()()); + + static_assert(IsUniquePtr<type>::value, "Factories must return a unique_ptr"); +}; + +template <typename Factory> +using FactoryPtrType = typename FactoryPtrTypeHelper<Factory>::type; + +template <typename Factory> +using FactoryElementType = typename FactoryPtrType<Factory>::element_type; + +template <typename T> +class ExceptionSafetyTest { + using Factory = std::function<std::unique_ptr<T>()>; + using Operation = std::function<void(T*)>; + using Contract = std::function<AssertionResult(T*)>; + + public: + template <typename... Contracts> + explicit ExceptionSafetyTest(const Factory& f, const Operation& op, + const Contracts&... contracts) + : factory_(f), operation_(op), contracts_{WrapContract(contracts)...} {} + + AssertionResult Test() const { + for (int count = 0;; ++count) { + exceptions_internal::ConstructorTracker ct(count); + + for (const auto& contract : contracts_) { + auto t_ptr = factory_(); + try { + SetCountdown(count); + operation_(t_ptr.get()); + // Unset for the case that the operation throws no exceptions, which + // would leave the countdown set and break the *next* exception safety + // test after this one. + UnsetCountdown(); + return AssertionSuccess(); + } catch (const exceptions_internal::TestException& e) { + if (!contract(t_ptr.get())) { + return AssertionFailure() << e.what() << " failed contract check"; + } + } + } + } + } + + private: + template <typename ContractFn> + Contract WrapContract(const ContractFn& contract) { + return [contract](T* t_ptr) { return AssertionResult(contract(t_ptr)); }; + } + + Contract WrapContract(StrongGuaranteeTagType) { + return [this](T* t_ptr) { return AssertionResult(*factory_() == *t_ptr); }; + } + + Factory factory_; + Operation operation_; + std::vector<Contract> contracts_; +}; + +/* + * Builds a tester object that tests if performing a operation on a T follows + * exception safety guarantees. Verification is done via contract assertion + * callbacks applied to T instances post-throw. + * + * Template parameters for ExceptionSafetyTestBuilder: + * + * - Factory: The factory object (passed in via tester.WithFactory(...) or + * tester.WithInitialValue(...)) must be invocable with the signature + * `std::unique_ptr<T> operator()() const` where T is the type being tested. + * It is used for reliably creating identical T instances to test on. + * + * - Operation: The operation object (passsed in via tester.WithOperation(...) + * or tester.Test(...)) must be invocable with the signature + * `void operator()(T*) const` where T is the type being tested. It is used + * for performing steps on a T instance that may throw and that need to be + * checked for exception safety. Each call to the operation will receive a + * fresh T instance so it's free to modify and destroy the T instances as it + * pleases. + * + * - Contracts...: The contract assertion callback objects (passed in via + * tester.WithContracts(...)) must be invocable with the signature + * `testing::AssertionResult operator()(T*) const` where T is the type being + * tested. Contract assertion callbacks are provided T instances post-throw. + * They must return testing::AssertionSuccess when the type contracts of the + * provided T instance hold. If the type contracts of the T instance do not + * hold, they must return testing::AssertionFailure. Execution order of + * Contracts... is unspecified. They will each individually get a fresh T + * instance so they are free to modify and destroy the T instances as they + * please. + */ +template <typename Factory, typename Operation, typename... Contracts> +class ExceptionSafetyTestBuilder { + public: + /* + * Returns a new ExceptionSafetyTestBuilder with an included T factory based + * on the provided T instance. The existing factory will not be included in + * the newly created tester instance. The created factory returns a new T + * instance by copy-constructing the provided const T& t. + * + * Preconditions for tester.WithInitialValue(const T& t): + * + * - The const T& t object must be copy-constructible where T is the type + * being tested. For non-copy-constructible objects, use the method + * tester.WithFactory(...). + */ + template <typename T> + ExceptionSafetyTestBuilder<DefaultFactory<T>, Operation, Contracts...> + WithInitialValue(const T& t) const { + return WithFactory(DefaultFactory<T>(t)); + } + + /* + * Returns a new ExceptionSafetyTestBuilder with the provided T factory + * included. The existing factory will not be included in the newly-created + * tester instance. This method is intended for use with types lacking a copy + * constructor. Types that can be copy-constructed should instead use the + * method tester.WithInitialValue(...). + */ + template <typename NewFactory> + ExceptionSafetyTestBuilder<absl::decay_t<NewFactory>, Operation, Contracts...> + WithFactory(const NewFactory& new_factory) const { + return {new_factory, operation_, contracts_}; + } + + /* + * Returns a new ExceptionSafetyTestBuilder with the provided testable + * operation included. The existing operation will not be included in the + * newly created tester. + */ + template <typename NewOperation> + ExceptionSafetyTestBuilder<Factory, absl::decay_t<NewOperation>, Contracts...> + WithOperation(const NewOperation& new_operation) const { + return {factory_, new_operation, contracts_}; + } + + /* + * Returns a new ExceptionSafetyTestBuilder with the provided MoreContracts... + * combined with the Contracts... that were already included in the instance + * on which the method was called. Contracts... cannot be removed or replaced + * once added to an ExceptionSafetyTestBuilder instance. A fresh object must + * be created in order to get an empty Contracts... list. + * + * In addition to passing in custom contract assertion callbacks, this method + * accepts `testing::strong_guarantee` as an argument which checks T instances + * post-throw against freshly created T instances via operator== to verify + * that any state changes made during the execution of the operation were + * properly rolled back. + */ + template <typename... MoreContracts> + ExceptionSafetyTestBuilder<Factory, Operation, Contracts..., + absl::decay_t<MoreContracts>...> + WithContracts(const MoreContracts&... more_contracts) const { + return { + factory_, operation_, + std::tuple_cat(contracts_, std::tuple<absl::decay_t<MoreContracts>...>( + more_contracts...))}; + } + + /* + * Returns a testing::AssertionResult that is the reduced result of the + * exception safety algorithm. The algorithm short circuits and returns + * AssertionFailure after the first contract callback returns an + * AssertionFailure. Otherwise, if all contract callbacks return an + * AssertionSuccess, the reduced result is AssertionSuccess. + * + * The passed-in testable operation will not be saved in a new tester instance + * nor will it modify/replace the existing tester instance. This is useful + * when each operation being tested is unique and does not need to be reused. + * + * Preconditions for tester.Test(const NewOperation& new_operation): + * + * - May only be called after at least one contract assertion callback and a + * factory or initial value have been provided. + */ + template < + typename NewOperation, + typename = EnableIfTestable<sizeof...(Contracts), Factory, NewOperation>> + testing::AssertionResult Test(const NewOperation& new_operation) const { + return TestImpl(new_operation, absl::index_sequence_for<Contracts...>()); + } + + /* + * Returns a testing::AssertionResult that is the reduced result of the + * exception safety algorithm. The algorithm short circuits and returns + * AssertionFailure after the first contract callback returns an + * AssertionFailure. Otherwise, if all contract callbacks return an + * AssertionSuccess, the reduced result is AssertionSuccess. + * + * Preconditions for tester.Test(): + * + * - May only be called after at least one contract assertion callback, a + * factory or initial value and a testable operation have been provided. + */ + template < + typename LazyOperation = Operation, + typename = EnableIfTestable<sizeof...(Contracts), Factory, LazyOperation>> + testing::AssertionResult Test() const { + return Test(operation_); + } + + private: + template <typename, typename, typename...> + friend class ExceptionSafetyTestBuilder; + + friend ExceptionSafetyTestBuilder<> testing::MakeExceptionSafetyTester(); + + ExceptionSafetyTestBuilder() {} + + ExceptionSafetyTestBuilder(const Factory& f, const Operation& o, + const std::tuple<Contracts...>& i) + : factory_(f), operation_(o), contracts_(i) {} + + template <typename SelectedOperation, size_t... Indices> + testing::AssertionResult TestImpl(SelectedOperation selected_operation, + absl::index_sequence<Indices...>) const { + return ExceptionSafetyTest<FactoryElementType<Factory>>( + factory_, selected_operation, std::get<Indices>(contracts_)...) + .Test(); + } + + Factory factory_; + Operation operation_; + std::tuple<Contracts...> contracts_; +}; + +} // namespace exceptions_internal + +} // namespace testing + +#endif // ABSL_HAVE_EXCEPTIONS + +#endif // ABSL_BASE_INTERNAL_EXCEPTION_SAFETY_TESTING_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/exception_testing.h b/third_party/abseil-cpp/absl/base/internal/exception_testing.h new file mode 100644 index 0000000000..01b5465571 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/exception_testing.h @@ -0,0 +1,42 @@ +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/exponential_biased.cc b/third_party/abseil-cpp/absl/base/internal/exponential_biased.cc new file mode 100644 index 0000000000..1b30c061e3 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/exponential_biased.cc @@ -0,0 +1,93 @@ +// 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/exponential_biased.h" + +#include <stdint.h> + +#include <algorithm> +#include <atomic> +#include <cmath> +#include <limits> + +#include "absl/base/attributes.h" +#include "absl/base/optimization.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +// The algorithm generates a random number between 0 and 1 and applies the +// inverse cumulative distribution function for an exponential. Specifically: +// Let m be the inverse of the sample period, then the probability +// distribution function is m*exp(-mx) so the CDF is +// p = 1 - exp(-mx), so +// q = 1 - p = exp(-mx) +// log_e(q) = -mx +// -log_e(q)/m = x +// log_2(q) * (-log_e(2) * 1/m) = x +// In the code, q is actually in the range 1 to 2**26, hence the -26 below +int64_t ExponentialBiased::GetSkipCount(int64_t mean) { + if (ABSL_PREDICT_FALSE(!initialized_)) { + Initialize(); + } + + uint64_t rng = NextRandom(rng_); + rng_ = rng; + + // Take the top 26 bits as the random number + // (This plus the 1<<58 sampling bound give a max possible step of + // 5194297183973780480 bytes.) + // The uint32_t cast is to prevent a (hard-to-reproduce) NAN + // under piii debug for some binaries. + double q = static_cast<uint32_t>(rng >> (kPrngNumBits - 26)) + 1.0; + // Put the computed p-value through the CDF of a geometric. + double interval = bias_ + (std::log2(q) - 26) * (-std::log(2.0) * mean); + // Very large values of interval overflow int64_t. To avoid that, we will + // cheat and clamp any huge values to (int64_t max)/2. This is a potential + // source of bias, but the mean would need to be such a large value that it's + // not likely to come up. For example, with a mean of 1e18, the probability of + // hitting this condition is about 1/1000. For a mean of 1e17, standard + // calculators claim that this event won't happen. + if (interval > static_cast<double>(std::numeric_limits<int64_t>::max() / 2)) { + // Assume huge values are bias neutral, retain bias for next call. + return std::numeric_limits<int64_t>::max() / 2; + } + double value = std::round(interval); + bias_ = interval - value; + return value; +} + +int64_t ExponentialBiased::GetStride(int64_t mean) { + return GetSkipCount(mean - 1) + 1; +} + +void ExponentialBiased::Initialize() { + // We don't get well distributed numbers from `this` so we call NextRandom() a + // bunch to mush the bits around. We use a global_rand to handle the case + // where the same thread (by memory address) gets created and destroyed + // repeatedly. + ABSL_CONST_INIT static std::atomic<uint32_t> global_rand(0); + uint64_t r = reinterpret_cast<uint64_t>(this) + + global_rand.fetch_add(1, std::memory_order_relaxed); + for (int i = 0; i < 20; ++i) { + r = NextRandom(r); + } + rng_ = r; + initialized_ = true; +} + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/exponential_biased.h b/third_party/abseil-cpp/absl/base/internal/exponential_biased.h new file mode 100644 index 0000000000..94f79a3378 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/exponential_biased.h @@ -0,0 +1,130 @@ +// 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_EXPONENTIAL_BIASED_H_ +#define ABSL_BASE_INTERNAL_EXPONENTIAL_BIASED_H_ + +#include <stdint.h> + +#include "absl/base/config.h" +#include "absl/base/macros.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +// ExponentialBiased provides a small and fast random number generator for a +// rounded exponential distribution. This generator manages very little state, +// and imposes no synchronization overhead. This makes it useful in specialized +// scenarios requiring minimum overhead, such as stride based periodic sampling. +// +// ExponentialBiased provides two closely related functions, GetSkipCount() and +// GetStride(), both returning a rounded integer defining a number of events +// required before some event with a given mean probability occurs. +// +// The distribution is useful to generate a random wait time or some periodic +// event with a given mean probability. For example, if an action is supposed to +// happen on average once every 'N' events, then we can get a random 'stride' +// counting down how long before the event to happen. For example, if we'd want +// to sample one in every 1000 'Frobber' calls, our code could look like this: +// +// Frobber::Frobber() { +// stride_ = exponential_biased_.GetStride(1000); +// } +// +// void Frobber::Frob(int arg) { +// if (--stride == 0) { +// SampleFrob(arg); +// stride_ = exponential_biased_.GetStride(1000); +// } +// ... +// } +// +// The rounding of the return value creates a bias, especially for smaller means +// where the distribution of the fraction is not evenly distributed. We correct +// this bias by tracking the fraction we rounded up or down on each iteration, +// effectively tracking the distance between the cumulative value, and the +// rounded cumulative value. For example, given a mean of 2: +// +// raw = 1.63076, cumulative = 1.63076, rounded = 2, bias = -0.36923 +// raw = 0.14624, cumulative = 1.77701, rounded = 2, bias = 0.14624 +// raw = 4.93194, cumulative = 6.70895, rounded = 7, bias = -0.06805 +// raw = 0.24206, cumulative = 6.95101, rounded = 7, bias = 0.24206 +// etc... +// +// Adjusting with rounding bias is relatively trivial: +// +// double value = bias_ + exponential_distribution(mean)(); +// double rounded_value = std::round(value); +// bias_ = value - rounded_value; +// return rounded_value; +// +// This class is thread-compatible. +class ExponentialBiased { + public: + // The number of bits set by NextRandom. + static constexpr int kPrngNumBits = 48; + + // `GetSkipCount()` returns the number of events to skip before some chosen + // event happens. For example, randomly tossing a coin, we will on average + // throw heads once before we get tails. We can simulate random coin tosses + // using GetSkipCount() as: + // + // ExponentialBiased eb; + // for (...) { + // int number_of_heads_before_tail = eb.GetSkipCount(1); + // for (int flips = 0; flips < number_of_heads_before_tail; ++flips) { + // printf("head..."); + // } + // printf("tail\n"); + // } + // + int64_t GetSkipCount(int64_t mean); + + // GetStride() returns the number of events required for a specific event to + // happen. See the class comments for a usage example. `GetStride()` is + // equivalent to `GetSkipCount(mean - 1) + 1`. When to use `GetStride()` or + // `GetSkipCount()` depends mostly on what best fits the use case. + int64_t GetStride(int64_t mean); + + // Computes a random number in the range [0, 1<<(kPrngNumBits+1) - 1] + // + // This is public to enable testing. + static uint64_t NextRandom(uint64_t rnd); + + private: + void Initialize(); + + uint64_t rng_{0}; + double bias_{0}; + bool initialized_{false}; +}; + +// Returns the next prng value. +// pRNG is: aX+b mod c with a = 0x5DEECE66D, b = 0xB, c = 1<<48 +// This is the lrand64 generator. +inline uint64_t ExponentialBiased::NextRandom(uint64_t rnd) { + const uint64_t prng_mult = uint64_t{0x5DEECE66D}; + const uint64_t prng_add = 0xB; + const uint64_t prng_mod_power = 48; + const uint64_t prng_mod_mask = + ~((~static_cast<uint64_t>(0)) << prng_mod_power); + return (prng_mult * rnd + prng_add) & prng_mod_mask; +} + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_EXPONENTIAL_BIASED_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/exponential_biased_test.cc b/third_party/abseil-cpp/absl/base/internal/exponential_biased_test.cc new file mode 100644 index 0000000000..90a482d2a9 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/exponential_biased_test.cc @@ -0,0 +1,199 @@ +// 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/exponential_biased.h" + +#include <stddef.h> + +#include <cmath> +#include <cstdint> +#include <vector> + +#include "gmock/gmock.h" +#include "gtest/gtest.h" +#include "absl/strings/str_cat.h" + +using ::testing::Ge; + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +MATCHER_P2(IsBetween, a, b, + absl::StrCat(std::string(negation ? "isn't" : "is"), " between ", a, + " and ", b)) { + return a <= arg && arg <= b; +} + +// Tests of the quality of the random numbers generated +// This uses the Anderson Darling test for uniformity. +// See "Evaluating the Anderson-Darling Distribution" by Marsaglia +// for details. + +// Short cut version of ADinf(z), z>0 (from Marsaglia) +// This returns the p-value for Anderson Darling statistic in +// the limit as n-> infinity. For finite n, apply the error fix below. +double AndersonDarlingInf(double z) { + if (z < 2) { + return exp(-1.2337141 / z) / sqrt(z) * + (2.00012 + + (0.247105 - + (0.0649821 - (0.0347962 - (0.011672 - 0.00168691 * z) * z) * z) * + z) * + z); + } + return exp( + -exp(1.0776 - + (2.30695 - + (0.43424 - (0.082433 - (0.008056 - 0.0003146 * z) * z) * z) * z) * + z)); +} + +// Corrects the approximation error in AndersonDarlingInf for small values of n +// Add this to AndersonDarlingInf to get a better approximation +// (from Marsaglia) +double AndersonDarlingErrFix(int n, double x) { + if (x > 0.8) { + return (-130.2137 + + (745.2337 - + (1705.091 - (1950.646 - (1116.360 - 255.7844 * x) * x) * x) * x) * + x) / + n; + } + double cutoff = 0.01265 + 0.1757 / n; + if (x < cutoff) { + double t = x / cutoff; + t = sqrt(t) * (1 - t) * (49 * t - 102); + return t * (0.0037 / (n * n) + 0.00078 / n + 0.00006) / n; + } else { + double t = (x - cutoff) / (0.8 - cutoff); + t = -0.00022633 + + (6.54034 - (14.6538 - (14.458 - (8.259 - 1.91864 * t) * t) * t) * t) * + t; + return t * (0.04213 + 0.01365 / n) / n; + } +} + +// Returns the AndersonDarling p-value given n and the value of the statistic +double AndersonDarlingPValue(int n, double z) { + double ad = AndersonDarlingInf(z); + double errfix = AndersonDarlingErrFix(n, ad); + return ad + errfix; +} + +double AndersonDarlingStatistic(const std::vector<double>& random_sample) { + int n = random_sample.size(); + double ad_sum = 0; + for (int i = 0; i < n; i++) { + ad_sum += (2 * i + 1) * + std::log(random_sample[i] * (1 - random_sample[n - 1 - i])); + } + double ad_statistic = -n - 1 / static_cast<double>(n) * ad_sum; + return ad_statistic; +} + +// Tests if the array of doubles is uniformly distributed. +// Returns the p-value of the Anderson Darling Statistic +// for the given set of sorted random doubles +// See "Evaluating the Anderson-Darling Distribution" by +// Marsaglia and Marsaglia for details. +double AndersonDarlingTest(const std::vector<double>& random_sample) { + double ad_statistic = AndersonDarlingStatistic(random_sample); + double p = AndersonDarlingPValue(random_sample.size(), ad_statistic); + return p; +} + +TEST(ExponentialBiasedTest, CoinTossDemoWithGetSkipCount) { + ExponentialBiased eb; + for (int runs = 0; runs < 10; ++runs) { + for (int flips = eb.GetSkipCount(1); flips > 0; --flips) { + printf("head..."); + } + printf("tail\n"); + } + int heads = 0; + for (int i = 0; i < 10000000; i += 1 + eb.GetSkipCount(1)) { + ++heads; + } + printf("Heads = %d (%f%%)\n", heads, 100.0 * heads / 10000000); +} + +TEST(ExponentialBiasedTest, SampleDemoWithStride) { + ExponentialBiased eb; + int stride = eb.GetStride(10); + int samples = 0; + for (int i = 0; i < 10000000; ++i) { + if (--stride == 0) { + ++samples; + stride = eb.GetStride(10); + } + } + printf("Samples = %d (%f%%)\n", samples, 100.0 * samples / 10000000); +} + + +// Testing that NextRandom generates uniform random numbers. Applies the +// Anderson-Darling test for uniformity +TEST(ExponentialBiasedTest, TestNextRandom) { + for (auto n : std::vector<int>({ + 10, // Check short-range correlation + 100, 1000, + 10000 // Make sure there's no systemic error + })) { + uint64_t x = 1; + // This assumes that the prng returns 48 bit numbers + uint64_t max_prng_value = static_cast<uint64_t>(1) << 48; + // Initialize. + for (int i = 1; i <= 20; i++) { + x = ExponentialBiased::NextRandom(x); + } + std::vector<uint64_t> int_random_sample(n); + // Collect samples + for (int i = 0; i < n; i++) { + int_random_sample[i] = x; + x = ExponentialBiased::NextRandom(x); + } + // First sort them... + std::sort(int_random_sample.begin(), int_random_sample.end()); + std::vector<double> random_sample(n); + // Convert them to uniform randoms (in the range [0,1]) + for (int i = 0; i < n; i++) { + random_sample[i] = + static_cast<double>(int_random_sample[i]) / max_prng_value; + } + // Now compute the Anderson-Darling statistic + double ad_pvalue = AndersonDarlingTest(random_sample); + EXPECT_GT(std::min(ad_pvalue, 1 - ad_pvalue), 0.0001) + << "prng is not uniform: n = " << n << " p = " << ad_pvalue; + } +} + +// The generator needs to be available as a thread_local and as a static +// variable. +TEST(ExponentialBiasedTest, InitializationModes) { + ABSL_CONST_INIT static ExponentialBiased eb_static; + EXPECT_THAT(eb_static.GetSkipCount(2), Ge(0)); + +#if ABSL_HAVE_THREAD_LOCAL + thread_local ExponentialBiased eb_thread; + EXPECT_THAT(eb_thread.GetSkipCount(2), Ge(0)); +#endif + + ExponentialBiased eb_stack; + EXPECT_THAT(eb_stack.GetSkipCount(2), Ge(0)); +} + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/hide_ptr.h b/third_party/abseil-cpp/absl/base/internal/hide_ptr.h new file mode 100644 index 0000000000..1dba80909a --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/hide_ptr.h @@ -0,0 +1,51 @@ +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/identity.h b/third_party/abseil-cpp/absl/base/internal/identity.h new file mode 100644 index 0000000000..a3154ed7bc --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/identity.h @@ -0,0 +1,37 @@ +// 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 { + +template <typename T> +struct identity { + typedef T type; +}; + +template <typename T> +using identity_t = typename identity<T>::type; + +} // namespace internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_IDENTITY_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/inline_variable.h b/third_party/abseil-cpp/absl/base/internal/inline_variable.h new file mode 100644 index 0000000000..130d8c2476 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/inline_variable.h @@ -0,0 +1,107 @@ +// 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_EMULATION_H_ +#define ABSL_BASE_INTERNAL_INLINE_VARIABLE_EMULATION_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: +// 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::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::identity_t<type> name = init + +#else + +// See above comment at top of file for details. +// +// Note: +// 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::identity_t<var_type> kInstance = init; \ + }; \ + \ + template <class AbslInternalDummy> \ + constexpr ::absl::internal::identity_t<var_type> \ + AbslInternalInlineVariableHolder##name<AbslInternalDummy>::kInstance; \ + \ + static constexpr const ::absl::internal::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_EMULATION_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/inline_variable_testing.h b/third_party/abseil-cpp/absl/base/internal/inline_variable_testing.h new file mode 100644 index 0000000000..3856b9f80f --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/inline_variable_testing.h @@ -0,0 +1,46 @@ +// 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_INLINE_VARIABLE_TESTING_H_ +#define ABSL_BASE_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_INLINE_VARIABLE_TESTING_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/invoke.h b/third_party/abseil-cpp/absl/base/internal/invoke.h new file mode 100644 index 0000000000..c4eceebd7c --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/invoke.h @@ -0,0 +1,187 @@ +// 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. +// +// [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 <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) { + return (std::forward<Obj>(obj).* + std::forward<MemFun>(mem_fun))(std::forward<Args>(args)...); + } +}; + +// ((*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 InvokeT = 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> +InvokeT<F, Args...> Invoke(F&& f, Args&&... args) { + return Invoker<F, Args...>::type::Invoke(std::forward<F>(f), + std::forward<Args>(args)...); +} +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_INVOKE_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/low_level_alloc.cc b/third_party/abseil-cpp/absl/base/internal/low_level_alloc.cc new file mode 100644 index 0000000000..1bf94438d6 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/low_level_alloc.cc @@ -0,0 +1,620 @@ +// 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 + +#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" + +// MAP_ANONYMOUS +#if defined(__APPLE__) +// For mmap, Linux defines both MAP_ANONYMOUS and MAP_ANON and says MAP_ANON is +// deprecated. In Darwin, MAP_ANON is all there is. +#if !defined MAP_ANONYMOUS +#define MAP_ANONYMOUS MAP_ANON +#endif // !MAP_ANONYMOUS +#endif // __APPLE__ + +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__) + return getpagesize(); +#else + return 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(int32_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, ®ion->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(0, 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); + } + +#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; + } + 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 diff --git a/third_party/abseil-cpp/absl/base/internal/low_level_alloc.h b/third_party/abseil-cpp/absl/base/internal/low_level_alloc.h new file mode 100644 index 0000000000..db91951c82 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/low_level_alloc.h @@ -0,0 +1,126 @@ +// 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__) +#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(int32_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_ diff --git a/third_party/abseil-cpp/absl/base/internal/low_level_alloc_test.cc b/third_party/abseil-cpp/absl/base/internal/low_level_alloc_test.cc new file mode 100644 index 0000000000..7abbbf9c59 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/low_level_alloc_test.cc @@ -0,0 +1,160 @@ +// 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> + +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 std::unordered_map<int, BlockDesc> AllocMap; + AllocMap allocated; + AllocMap::iterator it; + BlockDesc block_desc; + int rnd; + LowLevelAlloc::Arena *arena = 0; + 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 == 0 + ? 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"); + return 0; +} diff --git a/third_party/abseil-cpp/absl/base/internal/low_level_scheduling.h b/third_party/abseil-cpp/absl/base/internal/low_level_scheduling.h new file mode 100644 index 0000000000..961cc981b8 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/low_level_scheduling.h @@ -0,0 +1,107 @@ +// 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/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 +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(); + + 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; + }; + + // Access to SchedulingGuard is explicitly white-listed. + friend class SchedulingHelper; + friend class SpinLock; + + SchedulingGuard(const SchedulingGuard&) = delete; + SchedulingGuard& operator=(const SchedulingGuard&) = delete; +}; + +//------------------------------------------------------------------------------ +// End of public interfaces. +//------------------------------------------------------------------------------ + +inline bool SchedulingGuard::ReschedulingIsAllowed() { + return false; +} + +inline bool SchedulingGuard::DisableRescheduling() { + return false; +} + +inline void SchedulingGuard::EnableRescheduling(bool /* disable_result */) { + return; +} + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_LOW_LEVEL_SCHEDULING_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/per_thread_tls.h b/third_party/abseil-cpp/absl/base/internal/per_thread_tls.h new file mode 100644 index 0000000000..cf5e97a047 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/per_thread_tls.h @@ -0,0 +1,52 @@ +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/periodic_sampler.cc b/third_party/abseil-cpp/absl/base/internal/periodic_sampler.cc new file mode 100644 index 0000000000..520dabbaa0 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/periodic_sampler.cc @@ -0,0 +1,53 @@ +// 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/periodic_sampler.h" + +#include <atomic> + +#include "absl/base/internal/exponential_biased.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +int64_t PeriodicSamplerBase::GetExponentialBiased(int period) noexcept { + return rng_.GetStride(period); +} + +bool PeriodicSamplerBase::SubtleConfirmSample() noexcept { + int current_period = period(); + + // Deal with period case 0 (always off) and 1 (always on) + if (ABSL_PREDICT_FALSE(current_period < 2)) { + stride_ = 0; + return current_period == 1; + } + + // Check if this is the first call to Sample() + if (ABSL_PREDICT_FALSE(stride_ == 1)) { + stride_ = static_cast<uint64_t>(-GetExponentialBiased(current_period)); + if (static_cast<int64_t>(stride_) < -1) { + ++stride_; + return false; + } + } + + stride_ = static_cast<uint64_t>(-GetExponentialBiased(current_period)); + return true; +} + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/periodic_sampler.h b/third_party/abseil-cpp/absl/base/internal/periodic_sampler.h new file mode 100644 index 0000000000..f8a86796b1 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/periodic_sampler.h @@ -0,0 +1,211 @@ +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_BASE_INTERNAL_PERIODIC_SAMPLER_H_ +#define ABSL_BASE_INTERNAL_PERIODIC_SAMPLER_H_ + +#include <stdint.h> + +#include <atomic> + +#include "absl/base/internal/exponential_biased.h" +#include "absl/base/optimization.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +// PeriodicSamplerBase provides the basic period sampler implementation. +// +// This is the base class for the templated PeriodicSampler class, which holds +// a global std::atomic value identified by a user defined tag, such that +// each specific PeriodSampler implementation holds its own global period. +// +// PeriodicSamplerBase is thread-compatible except where stated otherwise. +class PeriodicSamplerBase { + public: + // PeriodicSamplerBase is trivial / copyable / movable / destructible. + PeriodicSamplerBase() = default; + PeriodicSamplerBase(PeriodicSamplerBase&&) = default; + PeriodicSamplerBase(const PeriodicSamplerBase&) = default; + + // Returns true roughly once every `period` calls. This is established by a + // randomly picked `stride` that is counted down on each call to `Sample`. + // This stride is picked such that the probability of `Sample()` returning + // true is 1 in `period`. + inline bool Sample() noexcept; + + // The below methods are intended for optimized use cases where the + // size of the inlined fast path code is highly important. Applications + // should use the `Sample()` method unless they have proof that their + // specific use case requires the optimizations offered by these methods. + // + // An example of such a use case is SwissTable sampling. All sampling checks + // are in inlined SwissTable methods, and the number of call sites is huge. + // In this case, the inlined code size added to each translation unit calling + // SwissTable methods is non-trivial. + // + // The `SubtleMaybeSample()` function spuriously returns true even if the + // function should not be sampled, applications MUST match each call to + // 'SubtleMaybeSample()' returning true with a `SubtleConfirmSample()` call, + // and use the result of the latter as the sampling decision. + // In other words: the code should logically be equivalent to: + // + // if (SubtleMaybeSample() && SubtleConfirmSample()) { + // // Sample this call + // } + // + // In the 'inline-size' optimized case, the `SubtleConfirmSample()` call can + // be placed out of line, for example, the typical use case looks as follows: + // + // // --- frobber.h ----------- + // void FrobberSampled(); + // + // inline void FrobberImpl() { + // // ... + // } + // + // inline void Frobber() { + // if (ABSL_PREDICT_FALSE(sampler.SubtleMaybeSample())) { + // FrobberSampled(); + // } else { + // FrobberImpl(); + // } + // } + // + // // --- frobber.cc ----------- + // void FrobberSampled() { + // if (!sampler.SubtleConfirmSample())) { + // // Spurious false positive + // FrobberImpl(); + // return; + // } + // + // // Sampled execution + // // ... + // } + inline bool SubtleMaybeSample() noexcept; + bool SubtleConfirmSample() noexcept; + + protected: + // We explicitly don't use a virtual destructor as this class is never + // virtually destroyed, and it keeps the class trivial, which avoids TLS + // prologue and epilogue code for our TLS instances. + ~PeriodicSamplerBase() = default; + + // Returns the next stride for our sampler. + // This function is virtual for testing purposes only. + virtual int64_t GetExponentialBiased(int period) noexcept; + + private: + // Returns the current period of this sampler. Thread-safe. + virtual int period() const noexcept = 0; + + // Keep and decrement stride_ as an unsigned integer, but compare the value + // to zero casted as a signed int. clang and msvc do not create optimum code + // if we use signed for the combined decrement and sign comparison. + // + // Below 3 alternative options, all compiles generate the best code + // using the unsigned increment <---> signed int comparison option. + // + // Option 1: + // int64_t stride_; + // if (ABSL_PREDICT_TRUE(++stride_ < 0)) { ... } + // + // GCC x64 (OK) : https://gcc.godbolt.org/z/R5MzzA + // GCC ppc (OK) : https://gcc.godbolt.org/z/z7NZAt + // Clang x64 (BAD): https://gcc.godbolt.org/z/t4gPsd + // ICC x64 (OK) : https://gcc.godbolt.org/z/rE6s8W + // MSVC x64 (OK) : https://gcc.godbolt.org/z/ARMXqS + // + // Option 2: + // int64_t stride_ = 0; + // if (ABSL_PREDICT_TRUE(--stride_ >= 0)) { ... } + // + // GCC x64 (OK) : https://gcc.godbolt.org/z/jSQxYK + // GCC ppc (OK) : https://gcc.godbolt.org/z/VJdYaA + // Clang x64 (BAD): https://gcc.godbolt.org/z/Xm4NjX + // ICC x64 (OK) : https://gcc.godbolt.org/z/4snaFd + // MSVC x64 (BAD): https://gcc.godbolt.org/z/BgnEKE + // + // Option 3: + // uint64_t stride_; + // if (ABSL_PREDICT_TRUE(static_cast<int64_t>(++stride_) < 0)) { ... } + // + // GCC x64 (OK) : https://gcc.godbolt.org/z/bFbfPy + // GCC ppc (OK) : https://gcc.godbolt.org/z/S9KkUE + // Clang x64 (OK) : https://gcc.godbolt.org/z/UYzRb4 + // ICC x64 (OK) : https://gcc.godbolt.org/z/ptTNfD + // MSVC x64 (OK) : https://gcc.godbolt.org/z/76j4-5 + uint64_t stride_ = 0; + ExponentialBiased rng_; +}; + +inline bool PeriodicSamplerBase::SubtleMaybeSample() noexcept { + // See comments on `stride_` for the unsigned increment / signed compare. + if (ABSL_PREDICT_TRUE(static_cast<int64_t>(++stride_) < 0)) { + return false; + } + return true; +} + +inline bool PeriodicSamplerBase::Sample() noexcept { + return ABSL_PREDICT_FALSE(SubtleMaybeSample()) ? SubtleConfirmSample() + : false; +} + +// PeriodicSampler is a concreted periodic sampler implementation. +// The user provided Tag identifies the implementation, and is required to +// isolate the global state of this instance from other instances. +// +// Typical use case: +// +// struct HashTablezTag {}; +// thread_local PeriodicSampler sampler; +// +// void HashTableSamplingLogic(...) { +// if (sampler.Sample()) { +// HashTableSlowSamplePath(...); +// } +// } +// +template <typename Tag, int default_period = 0> +class PeriodicSampler final : public PeriodicSamplerBase { + public: + ~PeriodicSampler() = default; + + int period() const noexcept final { + return period_.load(std::memory_order_relaxed); + } + + // Sets the global period for this sampler. Thread-safe. + // Setting a period of 0 disables the sampler, i.e., every call to Sample() + // will return false. Setting a period of 1 puts the sampler in 'always on' + // mode, i.e., every call to Sample() returns true. + static void SetGlobalPeriod(int period) { + period_.store(period, std::memory_order_relaxed); + } + + private: + static std::atomic<int> period_; +}; + +template <typename Tag, int default_period> +std::atomic<int> PeriodicSampler<Tag, default_period>::period_(default_period); + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_PERIODIC_SAMPLER_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/periodic_sampler_benchmark.cc b/third_party/abseil-cpp/absl/base/internal/periodic_sampler_benchmark.cc new file mode 100644 index 0000000000..5ad469ce79 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/periodic_sampler_benchmark.cc @@ -0,0 +1,79 @@ +// 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 "benchmark/benchmark.h" +#include "absl/base/internal/periodic_sampler.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { +namespace { + +template <typename Sampler> +void BM_Sample(Sampler* sampler, benchmark::State& state) { + for (auto _ : state) { + benchmark::DoNotOptimize(sampler); + benchmark::DoNotOptimize(sampler->Sample()); + } +} + +template <typename Sampler> +void BM_SampleMinunumInlined(Sampler* sampler, benchmark::State& state) { + for (auto _ : state) { + benchmark::DoNotOptimize(sampler); + if (ABSL_PREDICT_FALSE(sampler->SubtleMaybeSample())) { + benchmark::DoNotOptimize(sampler->SubtleConfirmSample()); + } + } +} + +void BM_PeriodicSampler_TinySample(benchmark::State& state) { + struct Tag {}; + PeriodicSampler<Tag, 10> sampler; + BM_Sample(&sampler, state); +} +BENCHMARK(BM_PeriodicSampler_TinySample); + +void BM_PeriodicSampler_ShortSample(benchmark::State& state) { + struct Tag {}; + PeriodicSampler<Tag, 1024> sampler; + BM_Sample(&sampler, state); +} +BENCHMARK(BM_PeriodicSampler_ShortSample); + +void BM_PeriodicSampler_LongSample(benchmark::State& state) { + struct Tag {}; + PeriodicSampler<Tag, 1024 * 1024> sampler; + BM_Sample(&sampler, state); +} +BENCHMARK(BM_PeriodicSampler_LongSample); + +void BM_PeriodicSampler_LongSampleMinunumInlined(benchmark::State& state) { + struct Tag {}; + PeriodicSampler<Tag, 1024 * 1024> sampler; + BM_SampleMinunumInlined(&sampler, state); +} +BENCHMARK(BM_PeriodicSampler_LongSampleMinunumInlined); + +void BM_PeriodicSampler_Disabled(benchmark::State& state) { + struct Tag {}; + PeriodicSampler<Tag, 0> sampler; + BM_Sample(&sampler, state); +} +BENCHMARK(BM_PeriodicSampler_Disabled); + +} // namespace +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/periodic_sampler_test.cc b/third_party/abseil-cpp/absl/base/internal/periodic_sampler_test.cc new file mode 100644 index 0000000000..3b301e37ab --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/periodic_sampler_test.cc @@ -0,0 +1,177 @@ +// 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/periodic_sampler.h" + +#include <thread> // NOLINT(build/c++11) + +#include "gmock/gmock.h" +#include "gtest/gtest.h" +#include "absl/base/attributes.h" +#include "absl/base/macros.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { +namespace { + +using testing::Eq; +using testing::Return; +using testing::StrictMock; + +class MockPeriodicSampler : public PeriodicSamplerBase { + public: + virtual ~MockPeriodicSampler() = default; + + MOCK_METHOD(int, period, (), (const, noexcept)); + MOCK_METHOD(int64_t, GetExponentialBiased, (int), (noexcept)); +}; + +TEST(PeriodicSamplerBaseTest, Sample) { + StrictMock<MockPeriodicSampler> sampler; + + EXPECT_CALL(sampler, period()).Times(3).WillRepeatedly(Return(16)); + EXPECT_CALL(sampler, GetExponentialBiased(16)) + .WillOnce(Return(2)) + .WillOnce(Return(3)) + .WillOnce(Return(4)); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_TRUE(sampler.Sample()); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); + EXPECT_TRUE(sampler.Sample()); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); +} + +TEST(PeriodicSamplerBaseTest, ImmediatelySample) { + StrictMock<MockPeriodicSampler> sampler; + + EXPECT_CALL(sampler, period()).Times(2).WillRepeatedly(Return(16)); + EXPECT_CALL(sampler, GetExponentialBiased(16)) + .WillOnce(Return(1)) + .WillOnce(Return(2)) + .WillOnce(Return(3)); + + EXPECT_TRUE(sampler.Sample()); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_TRUE(sampler.Sample()); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); +} + +TEST(PeriodicSamplerBaseTest, Disabled) { + StrictMock<MockPeriodicSampler> sampler; + + EXPECT_CALL(sampler, period()).Times(3).WillRepeatedly(Return(0)); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); +} + +TEST(PeriodicSamplerBaseTest, AlwaysOn) { + StrictMock<MockPeriodicSampler> sampler; + + EXPECT_CALL(sampler, period()).Times(3).WillRepeatedly(Return(1)); + + EXPECT_TRUE(sampler.Sample()); + EXPECT_TRUE(sampler.Sample()); + EXPECT_TRUE(sampler.Sample()); +} + +TEST(PeriodicSamplerBaseTest, Disable) { + StrictMock<MockPeriodicSampler> sampler; + + EXPECT_CALL(sampler, period()).WillOnce(Return(16)); + EXPECT_CALL(sampler, GetExponentialBiased(16)).WillOnce(Return(3)); + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); + + EXPECT_CALL(sampler, period()).Times(2).WillRepeatedly(Return(0)); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); +} + +TEST(PeriodicSamplerBaseTest, Enable) { + StrictMock<MockPeriodicSampler> sampler; + + EXPECT_CALL(sampler, period()).WillOnce(Return(0)); + EXPECT_FALSE(sampler.Sample()); + + EXPECT_CALL(sampler, period()).Times(2).WillRepeatedly(Return(16)); + EXPECT_CALL(sampler, GetExponentialBiased(16)) + .Times(2) + .WillRepeatedly(Return(3)); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); + EXPECT_TRUE(sampler.Sample()); + + EXPECT_FALSE(sampler.Sample()); + EXPECT_FALSE(sampler.Sample()); +} + +TEST(PeriodicSamplerTest, ConstructConstInit) { + struct Tag {}; + ABSL_CONST_INIT static PeriodicSampler<Tag> sampler; + (void)sampler; +} + +TEST(PeriodicSamplerTest, DefaultPeriod0) { + struct Tag {}; + PeriodicSampler<Tag> sampler; + EXPECT_THAT(sampler.period(), Eq(0)); +} + +TEST(PeriodicSamplerTest, DefaultPeriod) { + struct Tag {}; + PeriodicSampler<Tag, 100> sampler; + EXPECT_THAT(sampler.period(), Eq(100)); +} + +TEST(PeriodicSamplerTest, SetGlobalPeriod) { + struct Tag1 {}; + struct Tag2 {}; + PeriodicSampler<Tag1, 25> sampler1; + PeriodicSampler<Tag2, 50> sampler2; + + EXPECT_THAT(sampler1.period(), Eq(25)); + EXPECT_THAT(sampler2.period(), Eq(50)); + + std::thread thread([] { + PeriodicSampler<Tag1, 25> sampler1; + PeriodicSampler<Tag2, 50> sampler2; + EXPECT_THAT(sampler1.period(), Eq(25)); + EXPECT_THAT(sampler2.period(), Eq(50)); + sampler1.SetGlobalPeriod(10); + sampler2.SetGlobalPeriod(20); + }); + thread.join(); + + EXPECT_THAT(sampler1.period(), Eq(10)); + EXPECT_THAT(sampler2.period(), Eq(20)); +} + +} // namespace +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/pretty_function.h b/third_party/abseil-cpp/absl/base/internal/pretty_function.h new file mode 100644 index 0000000000..35d51676dc --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/pretty_function.h @@ -0,0 +1,33 @@ +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/raw_logging.cc b/third_party/abseil-cpp/absl/base/internal/raw_logging.cc new file mode 100644 index 0000000000..40cea55061 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/raw_logging.cc @@ -0,0 +1,240 @@ +// 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 <stddef.h> +#include <cstdarg> +#include <cstdio> +#include <cstdlib> +#include <cstring> + +#include "absl/base/attributes.h" +#include "absl/base/config.h" +#include "absl/base/internal/atomic_hook.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(__Fuchsia__) || defined(__native_client__) || \ + 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 + +// 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 +// whitelisted set of platforms for which we expect not to be able to raw log. + +ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static absl::base_internal::AtomicHook< + absl::raw_logging_internal::LogPrefixHook> + log_prefix_hook; +ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static absl::base_internal::AtomicHook< + absl::raw_logging_internal::AbortHook> + abort_hook; + +#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED +static const 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[]. +inline static bool VADoRawLog(char** buf, int* size, const char* format, + va_list ap) ABSL_PRINTF_ATTRIBUTE(3, 0); +inline static bool VADoRawLog(char** buf, int* size, + const char* format, va_list ap) { + int n = vsnprintf(*buf, *size, format, ap); + bool result = true; + if (n < 0 || n > *size) { + result = false; + if (static_cast<size_t>(*size) > sizeof(kTruncated)) { + n = *size - sizeof(kTruncated); // room for truncation message + } else { + n = 0; // no room for truncation message + } + } + *size -= n; + *buf += n; + return result; +} +#endif // ABSL_LOW_LEVEL_WRITE_SUPPORTED + +static constexpr int kLogBufSize = 3000; + +namespace { + +// 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, ...) { + va_list ap; + va_start(ap, format); + int n = vsnprintf(*buf, *size, format, ap); + va_end(ap); + if (n < 0 || n > *size) return false; + *size -= n; + *buf += n; + return true; +} + +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 + + auto log_prefix_hook_ptr = log_prefix_hook.Load(); + if (log_prefix_hook_ptr) { + enabled = log_prefix_hook_ptr(severity, file, line, &buf, &size); + } else { + if (enabled) { + DoRawLog(&buf, &size, "[%s : %d] RAW: ", file, line); + } + } + 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); + } + absl::raw_logging_internal::SafeWriteToStderr(buffer, strlen(buffer)); + } +#else + static_cast<void>(format); + static_cast<void>(ap); +#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(); + } +} + +} // namespace + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace raw_logging_internal { +void SafeWriteToStderr(const char *s, size_t len) { +#if defined(ABSL_HAVE_SYSCALL_WRITE) + 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, 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, ...) ABSL_PRINTF_ATTRIBUTE(4, 5); +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); +} + +// 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. +static void DefaultInternalLog(absl::LogSeverity severity, const char* file, + int line, const std::string& message) { + RawLog(severity, file, line, "%s", message.c_str()); +} + +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_DLL ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES + absl::base_internal::AtomicHook<InternalLogFunction> + internal_log_function(DefaultInternalLog); + +void RegisterInternalLogFunction(InternalLogFunction func) { + internal_log_function.Store(func); +} + +} // namespace raw_logging_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/raw_logging.h b/third_party/abseil-cpp/absl/base/internal/raw_logging.h new file mode 100644 index 0000000000..418d6c856f --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/raw_logging.h @@ -0,0 +1,183 @@ +// 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_logging_internal_basename = \ + ::absl::raw_logging_internal::Basename(__FILE__, \ + sizeof(__FILE__) - 1); \ + ::absl::raw_logging_internal::RawLog(ABSL_RAW_LOGGING_INTERNAL_##severity, \ + absl_raw_logging_internal_basename, \ + __LINE__, __VA_ARGS__); \ + } 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 { \ + ::absl::raw_logging_internal::internal_log_function( \ + ABSL_RAW_LOGGING_INTERNAL_##severity, __FILE__, __LINE__, message); \ + } 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) + +#define ABSL_RAW_LOGGING_INTERNAL_INFO ::absl::LogSeverity::kInfo +#define ABSL_RAW_LOGGING_INTERNAL_WARNING ::absl::LogSeverity::kWarning +#define ABSL_RAW_LOGGING_INTERNAL_ERROR ::absl::LogSeverity::kError +#define ABSL_RAW_LOGGING_INTERNAL_FATAL ::absl::LogSeverity::kFatal +#define ABSL_RAW_LOGGING_INTERNAL_LEVEL(severity) \ + ::absl::NormalizeLogSeverity(severity) + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace raw_logging_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 safe, low-level manner. +// +// In POSIX this means calling write(), which is async-signal safe and does +// not malloc. If the platform supports the SYS_write syscall, we invoke that +// directly to side-step any libc interception. +void SafeWriteToStderr(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_logging 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_logging 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. +// 'buffer' and 'buf_size' are pointers to the buffer and buffer size. If the +// hook writes a prefix, it must increment *buffer and decrement *buf_size +// accordingly. +using LogPrefixHook = bool (*)(absl::LogSeverity severity, const char* file, + int line, char** buffer, int* buf_size); + +// Function type for a raw_logging 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 LogPrefixHook.) +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_DLL ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES extern base_internal::AtomicHook< + InternalLogFunction> + internal_log_function; + +void RegisterInternalLogFunction(InternalLogFunction func); + +} // namespace raw_logging_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_RAW_LOGGING_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/scheduling_mode.h b/third_party/abseil-cpp/absl/base/internal/scheduling_mode.h new file mode 100644 index 0000000000..8be5ab6dd3 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/scheduling_mode.h @@ -0,0 +1,58 @@ +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/scoped_set_env.cc b/third_party/abseil-cpp/absl/base/internal/scoped_set_env.cc new file mode 100644 index 0000000000..8a934cb511 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/scoped_set_env.cc @@ -0,0 +1,81 @@ +// 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 diff --git a/third_party/abseil-cpp/absl/base/internal/scoped_set_env.h b/third_party/abseil-cpp/absl/base/internal/scoped_set_env.h new file mode 100644 index 0000000000..19ec7b5d8a --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/scoped_set_env.h @@ -0,0 +1,45 @@ +// +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/scoped_set_env_test.cc b/third_party/abseil-cpp/absl/base/internal/scoped_set_env_test.cc new file mode 100644 index 0000000000..5cbad246c6 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/scoped_set_env_test.cc @@ -0,0 +1,99 @@ +// 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 diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock.cc b/third_party/abseil-cpp/absl/base/internal/spinlock.cc new file mode 100644 index 0000000000..830d4729af --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock.cc @@ -0,0 +1,233 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/base/internal/spinlock.h" + +#include <algorithm> +#include <atomic> +#include <limits> + +#include "absl/base/attributes.h" +#include "absl/base/internal/atomic_hook.h" +#include "absl/base/internal/cycleclock.h" +#include "absl/base/internal/spinlock_wait.h" +#include "absl/base/internal/sysinfo.h" /* For NumCPUs() */ +#include "absl/base/call_once.h" + +// Description of lock-word: +// 31..00: [............................3][2][1][0] +// +// [0]: kSpinLockHeld +// [1]: kSpinLockCooperative +// [2]: kSpinLockDisabledScheduling +// [31..3]: ONLY kSpinLockSleeper OR +// Wait time in cycles >> PROFILE_TIMESTAMP_SHIFT +// +// Detailed descriptions: +// +// Bit [0]: The lock is considered held iff kSpinLockHeld is set. +// +// Bit [1]: Eligible waiters (e.g. Fibers) may co-operatively reschedule when +// contended iff kSpinLockCooperative is set. +// +// Bit [2]: This bit is exclusive from bit [1]. It is used only by a +// non-cooperative lock. When set, indicates that scheduling was +// successfully disabled when the lock was acquired. May be unset, +// even if non-cooperative, if a ThreadIdentity did not yet exist at +// time of acquisition. +// +// Bit [3]: If this is the only upper bit ([31..3]) set then this lock was +// acquired without contention, however, at least one waiter exists. +// +// Otherwise, bits [31..3] represent the time spent by the current lock +// holder to acquire the lock. There may be outstanding waiter(s). + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static base_internal::AtomicHook<void (*)( + const void *lock, int64_t wait_cycles)> + submit_profile_data; + +void RegisterSpinLockProfiler(void (*fn)(const void *contendedlock, + int64_t wait_cycles)) { + submit_profile_data.Store(fn); +} + +// Uncommon constructors. +SpinLock::SpinLock(base_internal::SchedulingMode mode) + : lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) { + ABSL_TSAN_MUTEX_CREATE(this, __tsan_mutex_not_static); +} + +SpinLock::SpinLock(base_internal::LinkerInitialized, + base_internal::SchedulingMode mode) { + ABSL_TSAN_MUTEX_CREATE(this, 0); + if (IsCooperative(mode)) { + InitLinkerInitializedAndCooperative(); + } + // Otherwise, lockword_ is already initialized. +} + +// Static (linker initialized) spinlocks always start life as functional +// non-cooperative locks. When their static constructor does run, it will call +// this initializer to augment the lockword with the cooperative bit. By +// actually taking the lock when we do this we avoid the need for an atomic +// operation in the regular unlock path. +// +// SlowLock() must be careful to re-test for this bit so that any outstanding +// waiters may be upgraded to cooperative status. +void SpinLock::InitLinkerInitializedAndCooperative() { + Lock(); + lockword_.fetch_or(kSpinLockCooperative, std::memory_order_relaxed); + Unlock(); +} + +// Monitor the lock to see if its value changes within some time period +// (adaptive_spin_count loop iterations). The last value read from the lock +// is returned from the method. +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; + } + // The lock was not obtained initially, so this thread needs to wait for + // it. Record the current timestamp in the local variable wait_start_time + // so the total wait time can be stored in the lockword once this thread + // obtains the lock. + int64_t wait_start_time = CycleClock::Now(); + uint32_t wait_cycles = 0; + int lock_wait_call_count = 0; + while ((lock_value & kSpinLockHeld) != 0) { + // If the lock is currently held, but not marked as having a sleeper, mark + // it as having a sleeper. + if ((lock_value & kWaitTimeMask) == 0) { + // Here, just "mark" that the thread is going to sleep. Don't store the + // lock wait time in the lock as that will cause the current lock + // owner to think it experienced contention. + if (lockword_.compare_exchange_strong( + lock_value, lock_value | kSpinLockSleeper, + std::memory_order_relaxed, std::memory_order_relaxed)) { + // Successfully transitioned to kSpinLockSleeper. Pass + // kSpinLockSleeper to the SpinLockWait routine to properly indicate + // the last lock_value observed. + lock_value |= kSpinLockSleeper; + } else if ((lock_value & kSpinLockHeld) == 0) { + // Lock is free again, so try and acquire it before sleeping. The + // new lock state will be the number of cycles this thread waited if + // this thread obtains the lock. + lock_value = TryLockInternal(lock_value, wait_cycles); + continue; // Skip the delay at the end of the loop. + } + } + + base_internal::SchedulingMode scheduling_mode; + if ((lock_value & kSpinLockCooperative) != 0) { + scheduling_mode = base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL; + } else { + scheduling_mode = base_internal::SCHEDULE_KERNEL_ONLY; + } + // SpinLockDelay() calls into fiber scheduler, we need to see + // synchronization there to avoid false positives. + ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0); + // Wait for an OS specific delay. + base_internal::SpinLockDelay(&lockword_, lock_value, ++lock_wait_call_count, + scheduling_mode); + ABSL_TSAN_MUTEX_POST_DIVERT(this, 0); + // Spin again after returning from the wait routine to give this thread + // some chance of obtaining the lock. + lock_value = SpinLoop(); + wait_cycles = EncodeWaitCycles(wait_start_time, CycleClock::Now()); + lock_value = TryLockInternal(lock_value, wait_cycles); + } +} + +void SpinLock::SlowUnlock(uint32_t lock_value) { + base_internal::SpinLockWake(&lockword_, + false); // wake waiter if necessary + + // If our acquisition was contended, collect contentionz profile info. We + // reserve a unitary wait time to represent that a waiter exists without our + // own acquisition having been contended. + if ((lock_value & kWaitTimeMask) != kSpinLockSleeper) { + const uint64_t wait_cycles = DecodeWaitCycles(lock_value); + ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0); + submit_profile_data(this, wait_cycles); + ABSL_TSAN_MUTEX_POST_DIVERT(this, 0); + } +} + +// We use the upper 29 bits of the lock word to store the time spent waiting to +// acquire this lock. This is reported by contentionz profiling. Since the +// lower bits of the cycle counter wrap very quickly on high-frequency +// processors we divide to reduce the granularity to 2^PROFILE_TIMESTAMP_SHIFT +// 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. +enum { PROFILE_TIMESTAMP_SHIFT = 7 }; +enum { LOCKWORD_RESERVED_SHIFT = 3 }; // We currently reserve the lower 3 bits. + +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() >> LOCKWORD_RESERVED_SHIFT; + int64_t scaled_wait_time = + (wait_end_time - wait_start_time) >> PROFILE_TIMESTAMP_SHIFT; + + // 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) << LOCKWORD_RESERVED_SHIFT); + + 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 << LOCKWORD_RESERVED_SHIFT); + if (clamped == kSpinLockSleeper) { + return kMinWaitTime; + } + return clamped; +} + +uint64_t SpinLock::DecodeWaitCycles(uint32_t lock_value) { + // Cast to uint32_t first to ensure bits [63:32] are cleared. + const uint64_t scaled_wait_time = + static_cast<uint32_t>(lock_value & kWaitTimeMask); + return scaled_wait_time + << (PROFILE_TIMESTAMP_SHIFT - LOCKWORD_RESERVED_SHIFT); +} + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock.h b/third_party/abseil-cpp/absl/base/internal/spinlock.h new file mode 100644 index 0000000000..24e2e9a6f8 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock.h @@ -0,0 +1,243 @@ +// +// 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 three situations: +// - for use in code that Mutex itself depends on +// - to get a faster fast-path release under low contention (without an +// atomic read-modify-write) In return, SpinLock has worse behaviour under +// contention, which is why Mutex is preferred in most situations. +// - for async signal safety (see below) + +// SpinLock 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. + +#ifndef ABSL_BASE_INTERNAL_SPINLOCK_H_ +#define ABSL_BASE_INTERNAL_SPINLOCK_H_ + +#include <stdint.h> +#include <sys/types.h> + +#include <atomic> + +#include "absl/base/attributes.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/macros.h" +#include "absl/base/port.h" +#include "absl/base/thread_annotations.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +class ABSL_LOCKABLE SpinLock { + public: + SpinLock() : lockword_(kSpinLockCooperative) { + ABSL_TSAN_MUTEX_CREATE(this, __tsan_mutex_not_static); + } + + // Special constructor for use with static SpinLock objects. E.g., + // + // static SpinLock lock(base_internal::kLinkerInitialized); + // + // When initialized using this constructor, we depend on the fact + // that the linker has already initialized the memory appropriately. The lock + // is initialized in non-cooperative mode. + // + // A SpinLock constructed like this can be freely used from global + // initializers without worrying about the order in which global + // initializers run. + explicit SpinLock(base_internal::LinkerInitialized) { + // Does nothing; lockword_ is already initialized + ABSL_TSAN_MUTEX_CREATE(this, 0); + } + + // 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); + SpinLock(base_internal::LinkerInitialized, + base_internal::SchedulingMode mode); + + ~SpinLock() { ABSL_TSAN_MUTEX_DESTROY(this, __tsan_mutex_not_static); } + + // 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. + 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()). + inline bool IsHeld() const { + return (lockword_.load(std::memory_order_relaxed) & kSpinLockHeld) != 0; + } + + 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 uint64_t DecodeWaitCycles(uint32_t lock_value); + + // Provide access to protected method above. Use for testing only. + friend struct SpinLockTest; + + 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 a lock disables scheduling. + // bit[3:31] encodes time a lock spent on waiting as a 29-bit unsigned int. + enum { kSpinLockHeld = 1 }; + enum { kSpinLockCooperative = 2 }; + enum { kSpinLockDisabledScheduling = 4 }; + enum { kSpinLockSleeper = 8 }; + enum { kWaitTimeMask = // Includes kSpinLockSleeper. + ~(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; + } + + uint32_t TryLockInternal(uint32_t lock_value, uint32_t wait_cycles); + void InitLinkerInitializedAndCooperative(); + 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. +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_ diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock_akaros.inc b/third_party/abseil-cpp/absl/base/internal/spinlock_akaros.inc new file mode 100644 index 0000000000..bc468940fc --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock_akaros.inc @@ -0,0 +1,35 @@ +// 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 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 AbslInternalSpinLockWake( + std::atomic<uint32_t>* /* lock_word */, bool /* all */) {} + +} // extern "C" diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock_benchmark.cc b/third_party/abseil-cpp/absl/base/internal/spinlock_benchmark.cc new file mode 100644 index 0000000000..0451c65f95 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock_benchmark.cc @@ -0,0 +1,52 @@ +// 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/synchronization/internal/create_thread_identity.h" +#include "benchmark/benchmark.h" + +namespace { + +template <absl::base_internal::SchedulingMode scheduling_mode> +static void BM_SpinLock(benchmark::State& state) { + // Ensure a ThreadIdentity is installed. + ABSL_INTERNAL_CHECK( + absl::synchronization_internal::GetOrCreateCurrentThreadIdentity() != + nullptr, + "GetOrCreateCurrentThreadIdentity() failed"); + + static auto* spinlock = new absl::base_internal::SpinLock(scheduling_mode); + for (auto _ : state) { + absl::base_internal::SpinLockHolder holder(spinlock); + } +} + +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(); + +} // namespace diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock_linux.inc b/third_party/abseil-cpp/absl/base/internal/spinlock_linux.inc new file mode 100644 index 0000000000..323edd62f4 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock_linux.inc @@ -0,0 +1,66 @@ +// 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 + +extern "C" { + +ABSL_ATTRIBUTE_WEAK void AbslInternalSpinLockDelay( + std::atomic<uint32_t> *w, uint32_t value, int loop, + absl::base_internal::SchedulingMode) { + absl::base_internal::ErrnoSaver errno_saver; + struct timespec tm; + tm.tv_sec = 0; + tm.tv_nsec = absl::base_internal::SpinLockSuggestedDelayNS(loop); + syscall(SYS_futex, w, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, value, &tm); +} + +ABSL_ATTRIBUTE_WEAK void AbslInternalSpinLockWake(std::atomic<uint32_t> *w, + bool all) { + syscall(SYS_futex, w, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, all ? INT_MAX : 1, 0); +} + +} // extern "C" diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock_posix.inc b/third_party/abseil-cpp/absl/base/internal/spinlock_posix.inc new file mode 100644 index 0000000000..fcd21b151b --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock_posix.inc @@ -0,0 +1,46 @@ +// 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 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 AbslInternalSpinLockWake( + std::atomic<uint32_t>* /* lock_word */, bool /* all */) {} + +} // extern "C" diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock_wait.cc b/third_party/abseil-cpp/absl/base/internal/spinlock_wait.cc new file mode 100644 index 0000000000..fa824be1c0 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock_wait.cc @@ -0,0 +1,81 @@ +// 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 diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock_wait.h b/third_party/abseil-cpp/absl/base/internal/spinlock_wait.h new file mode 100644 index 0000000000..169bc749fb --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock_wait.h @@ -0,0 +1,93 @@ +// 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. +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. This call is a hint, and on some +// systems it may be a no-op; 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 delay that can be truncated by a call to SpinLockWake(w). +// In all cases, it must return in bounded time even if SpinLockWake() is not +// called. +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 AbslInternalSpinLockWake(std::atomic<uint32_t> *w, bool all); +void 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) { + 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) { + AbslInternalSpinLockDelay(w, value, loop, scheduling_mode); +} + +#endif // ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/spinlock_win32.inc b/third_party/abseil-cpp/absl/base/internal/spinlock_win32.inc new file mode 100644 index 0000000000..78654b5b59 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/spinlock_win32.inc @@ -0,0 +1,37 @@ +// 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 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 { + Sleep(absl::base_internal::SpinLockSuggestedDelayNS(loop) / 1000000); + } +} + +void AbslInternalSpinLockWake(std::atomic<uint32_t>* /* lock_word */, + bool /* all */) {} + +} // extern "C" diff --git a/third_party/abseil-cpp/absl/base/internal/sysinfo.cc b/third_party/abseil-cpp/absl/base/internal/sysinfo.cc new file mode 100644 index 0000000000..a0930e9781 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/sysinfo.cc @@ -0,0 +1,416 @@ +// 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 + +#if defined(__myriad2__) +#include <rtems.h> +#endif + +#include <string.h> +#include <cassert> +#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/internal/raw_logging.h" +#include "absl/base/internal/spinlock.h" +#include "absl/base/internal/unscaledcycleclock.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +static int GetNumCPUs() { +#if defined(__myriad2__) + return 1; +#else + // Other possibilities: + // - Read /sys/devices/system/cpu/online and use cpumask_parse() + // - sysconf(_SC_NPROCESSORS_ONLN) + return std::thread::hardware_concurrency(); +#endif +} + +#if defined(_WIN32) + +static double GetNominalCPUFrequency() { +#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", 0, &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; +} + +#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; + int fd = open(file, O_RDONLY); + if (fd != -1) { + char line[1024]; + char *err; + memset(line, '\0', sizeof(line)); + int len = read(fd, line, sizeof(line) - 1); + 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) { + perror("clock_gettime() failed"); + abort(); + } + 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 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; +} + +#else + +// Fallback implementation of GetTID using pthread_getspecific. +static once_flag tid_once; +static pthread_key_t tid_key; +static absl::base_internal::SpinLock tid_lock( + absl::base_internal::kLinkerInitialized); + +// We set a bit per thread in this array to indicate that an ID is in +// use. ID 0 is unused because it is the default value returned by +// pthread_getspecific(). +static std::vector<uint32_t>* tid_array GUARDED_BY(tid_lock) = nullptr; +static constexpr int kBitsPerWord = 32; // tid_array is uint32_t. + +// Returns the TID to tid_array. +static void FreeTID(void *v) { + intptr_t tid = reinterpret_cast<intptr_t>(v); + int word = tid / kBitsPerWord; + uint32_t mask = ~(1u << (tid % kBitsPerWord)); + absl::base_internal::SpinLockHolder lock(&tid_lock); + assert(0 <= word && static_cast<size_t>(word) < tid_array->size()); + (*tid_array)[word] &= mask; +} + +static void InitGetTID() { + if (pthread_key_create(&tid_key, FreeTID) != 0) { + // The logging system calls GetTID() so it can't be used here. + perror("pthread_key_create failed"); + abort(); + } + + // Initialize tid_array. + absl::base_internal::SpinLockHolder lock(&tid_lock); + tid_array = new std::vector<uint32_t>(1); + (*tid_array)[0] = 1; // ID 0 is never-allocated. +} + +// Return a per-thread small integer ID from pthread's thread-specific data. +pid_t GetTID() { + absl::call_once(tid_once, InitGetTID); + + intptr_t tid = reinterpret_cast<intptr_t>(pthread_getspecific(tid_key)); + if (tid != 0) { + return tid; + } + + int bit; // tid_array[word] = 1u << bit; + size_t word; + { + // Search for the first unused ID. + absl::base_internal::SpinLockHolder lock(&tid_lock); + // First search for a word in the array that is not all ones. + word = 0; + while (word < tid_array->size() && ~(*tid_array)[word] == 0) { + ++word; + } + if (word == tid_array->size()) { + tid_array->push_back(0); // No space left, add kBitsPerWord more IDs. + } + // Search for a zero bit in the word. + bit = 0; + while (bit < kBitsPerWord && (((*tid_array)[word] >> bit) & 1) != 0) { + ++bit; + } + tid = (word * kBitsPerWord) + bit; + (*tid_array)[word] |= 1u << bit; // Mark the TID as allocated. + } + + if (pthread_setspecific(tid_key, reinterpret_cast<void *>(tid)) != 0) { + perror("pthread_setspecific failed"); + abort(); + } + + return static_cast<pid_t>(tid); +} + +#endif + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/sysinfo.h b/third_party/abseil-cpp/absl/base/internal/sysinfo.h new file mode 100644 index 0000000000..7246d5dd95 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/sysinfo.h @@ -0,0 +1,66 @@ +// 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/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(); + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_BASE_INTERNAL_SYSINFO_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/sysinfo_test.cc b/third_party/abseil-cpp/absl/base/internal/sysinfo_test.cc new file mode 100644 index 0000000000..fa8b88b1dc --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/sysinfo_test.cc @@ -0,0 +1,100 @@ +// 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, NominalCPUFrequency) { +#if !(defined(__aarch64__) && defined(__linux__)) && !defined(__EMSCRIPTEN__) + EXPECT_GE(NominalCPUFrequency(), 1000.0) + << "NominalCPUFrequency() did not return a reasonable value"; +#else + // Aarch64 cannot read the CPU frequency from sysfs, so we get back 1.0. + // Emscripten does not have a sysfs to read from at all. + EXPECT_EQ(NominalCPUFrequency(), 1.0) + << "CPU frequency detection was fixed! Please update unittest."; +#endif +} + +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 diff --git a/third_party/abseil-cpp/absl/base/internal/thread_annotations.h b/third_party/abseil-cpp/absl/base/internal/thread_annotations.h new file mode 100644 index 0000000000..4dab6a9c15 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/thread_annotations.h @@ -0,0 +1,271 @@ +// 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. +// +// ----------------------------------------------------------------------------- +// File: thread_annotations.h +// ----------------------------------------------------------------------------- +// +// WARNING: This is a backwards compatible header and it will be removed after +// the migration to prefixed thread annotations is finished; please include +// "absl/base/thread_annotations.h". +// +// This header file contains macro definitions for thread safety annotations +// that allow developers to document the locking policies of multi-threaded +// code. The annotations can also help program analysis tools to identify +// potential thread safety issues. +// +// These annotations are implemented using compiler attributes. Using the macros +// defined here instead of raw attributes allow for portability and future +// compatibility. +// +// When referring to mutexes in the arguments of the attributes, you should +// use variable names or more complex expressions (e.g. my_object->mutex_) +// that evaluate to a concrete mutex object whenever possible. If the mutex +// you want to refer to is not in scope, you may use a member pointer +// (e.g. &MyClass::mutex_) to refer to a mutex in some (unknown) object. + +#ifndef ABSL_BASE_INTERNAL_THREAD_ANNOTATIONS_H_ +#define ABSL_BASE_INTERNAL_THREAD_ANNOTATIONS_H_ + +#if defined(__clang__) +#define THREAD_ANNOTATION_ATTRIBUTE__(x) __attribute__((x)) +#else +#define THREAD_ANNOTATION_ATTRIBUTE__(x) // no-op +#endif + +// GUARDED_BY() +// +// Documents if a shared field or global variable needs to be protected by a +// mutex. GUARDED_BY() allows the user to specify a particular mutex that +// should be held when accessing the annotated variable. +// +// Although this annotation (and PT_GUARDED_BY, below) cannot be applied to +// local variables, a local variable and its associated mutex can often be +// combined into a small class or struct, thereby allowing the annotation. +// +// Example: +// +// class Foo { +// Mutex mu_; +// int p1_ GUARDED_BY(mu_); +// ... +// }; +#define GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x)) + +// PT_GUARDED_BY() +// +// Documents if the memory location pointed to by a pointer should be guarded +// by a mutex when dereferencing the pointer. +// +// Example: +// class Foo { +// Mutex mu_; +// int *p1_ PT_GUARDED_BY(mu_); +// ... +// }; +// +// Note that a pointer variable to a shared memory location could itself be a +// shared variable. +// +// Example: +// +// // `q_`, guarded by `mu1_`, points to a shared memory location that is +// // guarded by `mu2_`: +// int *q_ GUARDED_BY(mu1_) PT_GUARDED_BY(mu2_); +#define PT_GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x)) + +// ACQUIRED_AFTER() / ACQUIRED_BEFORE() +// +// Documents the acquisition order between locks that can be held +// simultaneously by a thread. For any two locks that need to be annotated +// to establish an acquisition order, only one of them needs the annotation. +// (i.e. You don't have to annotate both locks with both ACQUIRED_AFTER +// and ACQUIRED_BEFORE.) +// +// As with GUARDED_BY, this is only applicable to mutexes that are shared +// fields or global variables. +// +// Example: +// +// Mutex m1_; +// Mutex m2_ ACQUIRED_AFTER(m1_); +#define ACQUIRED_AFTER(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(__VA_ARGS__)) + +#define ACQUIRED_BEFORE(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(__VA_ARGS__)) + +// EXCLUSIVE_LOCKS_REQUIRED() / SHARED_LOCKS_REQUIRED() +// +// Documents a function that expects a mutex to be held prior to entry. +// The mutex is expected to be held both on entry to, and exit from, the +// function. +// +// An exclusive lock allows read-write access to the guarded data member(s), and +// only one thread can acquire a lock exclusively at any one time. A shared lock +// allows read-only access, and any number of threads can acquire a shared lock +// concurrently. +// +// Generally, non-const methods should be annotated with +// EXCLUSIVE_LOCKS_REQUIRED, while const methods should be annotated with +// SHARED_LOCKS_REQUIRED. +// +// Example: +// +// Mutex mu1, mu2; +// int a GUARDED_BY(mu1); +// int b GUARDED_BY(mu2); +// +// void foo() EXCLUSIVE_LOCKS_REQUIRED(mu1, mu2) { ... } +// void bar() const SHARED_LOCKS_REQUIRED(mu1, mu2) { ... } +#define EXCLUSIVE_LOCKS_REQUIRED(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(__VA_ARGS__)) + +#define SHARED_LOCKS_REQUIRED(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(shared_locks_required(__VA_ARGS__)) + +// LOCKS_EXCLUDED() +// +// Documents the locks acquired in the body of the function. These locks +// cannot be held when calling this function (as Abseil's `Mutex` locks are +// non-reentrant). +#define LOCKS_EXCLUDED(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(__VA_ARGS__)) + +// LOCK_RETURNED() +// +// Documents a function that returns a mutex without acquiring it. For example, +// a public getter method that returns a pointer to a private mutex should +// be annotated with LOCK_RETURNED. +#define LOCK_RETURNED(x) \ + THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x)) + +// LOCKABLE +// +// Documents if a class/type is a lockable type (such as the `Mutex` class). +#define LOCKABLE \ + THREAD_ANNOTATION_ATTRIBUTE__(lockable) + +// SCOPED_LOCKABLE +// +// Documents if a class does RAII locking (such as the `MutexLock` class). +// The constructor should use `LOCK_FUNCTION()` to specify the mutex that is +// acquired, and the destructor should use `UNLOCK_FUNCTION()` with no +// arguments; the analysis will assume that the destructor unlocks whatever the +// constructor locked. +#define SCOPED_LOCKABLE \ + THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable) + +// EXCLUSIVE_LOCK_FUNCTION() +// +// Documents functions that acquire a lock in the body of a function, and do +// not release it. +#define EXCLUSIVE_LOCK_FUNCTION(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(exclusive_lock_function(__VA_ARGS__)) + +// SHARED_LOCK_FUNCTION() +// +// Documents functions that acquire a shared (reader) lock in the body of a +// function, and do not release it. +#define SHARED_LOCK_FUNCTION(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(shared_lock_function(__VA_ARGS__)) + +// UNLOCK_FUNCTION() +// +// Documents functions that expect a lock to be held on entry to the function, +// and release it in the body of the function. +#define UNLOCK_FUNCTION(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(unlock_function(__VA_ARGS__)) + +// EXCLUSIVE_TRYLOCK_FUNCTION() / SHARED_TRYLOCK_FUNCTION() +// +// Documents functions that try to acquire a lock, and return success or failure +// (or a non-boolean value that can be interpreted as a boolean). +// The first argument should be `true` for functions that return `true` on +// success, or `false` for functions that return `false` on success. The second +// argument specifies the mutex that is locked on success. If unspecified, this +// mutex is assumed to be `this`. +#define EXCLUSIVE_TRYLOCK_FUNCTION(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(exclusive_trylock_function(__VA_ARGS__)) + +#define SHARED_TRYLOCK_FUNCTION(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(shared_trylock_function(__VA_ARGS__)) + +// ASSERT_EXCLUSIVE_LOCK() / ASSERT_SHARED_LOCK() +// +// Documents functions that dynamically check to see if a lock is held, and fail +// if it is not held. +#define ASSERT_EXCLUSIVE_LOCK(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(assert_exclusive_lock(__VA_ARGS__)) + +#define ASSERT_SHARED_LOCK(...) \ + THREAD_ANNOTATION_ATTRIBUTE__(assert_shared_lock(__VA_ARGS__)) + +// NO_THREAD_SAFETY_ANALYSIS +// +// Turns off thread safety checking within the body of a particular function. +// This annotation is used to mark functions that are known to be correct, but +// the locking behavior is more complicated than the analyzer can handle. +#define NO_THREAD_SAFETY_ANALYSIS \ + THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis) + +//------------------------------------------------------------------------------ +// Tool-Supplied Annotations +//------------------------------------------------------------------------------ + +// TS_UNCHECKED should be placed around lock expressions that are not valid +// C++ syntax, but which are present for documentation purposes. These +// annotations will be ignored by the analysis. +#define TS_UNCHECKED(x) "" + +// TS_FIXME is used to mark lock expressions that are not valid C++ syntax. +// It is used by automated tools to mark and disable invalid expressions. +// The annotation should either be fixed, or changed to TS_UNCHECKED. +#define TS_FIXME(x) "" + +// Like NO_THREAD_SAFETY_ANALYSIS, this turns off checking within the body of +// a particular function. However, this attribute is used to mark functions +// that are incorrect and need to be fixed. It is used by automated tools to +// avoid breaking the build when the analysis is updated. +// Code owners are expected to eventually fix the routine. +#define NO_THREAD_SAFETY_ANALYSIS_FIXME NO_THREAD_SAFETY_ANALYSIS + +// Similar to NO_THREAD_SAFETY_ANALYSIS_FIXME, this macro marks a GUARDED_BY +// annotation that needs to be fixed, because it is producing thread safety +// warning. It disables the GUARDED_BY. +#define GUARDED_BY_FIXME(x) + +// Disables warnings for a single read operation. This can be used to avoid +// warnings when it is known that the read is not actually involved in a race, +// but the compiler cannot confirm that. +#define TS_UNCHECKED_READ(x) thread_safety_analysis::ts_unchecked_read(x) + + +namespace thread_safety_analysis { + +// Takes a reference to a guarded data member, and returns an unguarded +// reference. +template <typename T> +inline const T& ts_unchecked_read(const T& v) NO_THREAD_SAFETY_ANALYSIS { + return v; +} + +template <typename T> +inline T& ts_unchecked_read(T& v) NO_THREAD_SAFETY_ANALYSIS { + return v; +} + +} // namespace thread_safety_analysis + +#endif // ABSL_BASE_INTERNAL_THREAD_ANNOTATIONS_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/thread_identity.cc b/third_party/abseil-cpp/absl/base/internal/thread_identity.cc new file mode 100644 index 0000000000..d63a04ae91 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/thread_identity.cc @@ -0,0 +1,152 @@ +// 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" + +#ifndef _WIN32 +#include <pthread.h> +#include <signal.h> +#endif + +#include <atomic> +#include <cassert> +#include <memory> + +#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. +#ifdef __GNUC__ +__attribute__((visibility("protected"))) +#endif // __GNUC__ +#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(__EMSCRIPTEN__) || defined(__MINGW32__) + // Emscripten 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. Because DLLs cannot expose thread_local variables in +// headers, we opt for the correct-but-slower option of placing the definition +// of this function only in a translation unit inside DLL. +#if defined(ABSL_BUILD_DLL) || defined(ABSL_CONSUME_DLL) +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 diff --git a/third_party/abseil-cpp/absl/base/internal/thread_identity.h b/third_party/abseil-cpp/absl/base/internal/thread_identity.h new file mode 100644 index 0000000000..ceb109b41c --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/thread_identity.h @@ -0,0 +1,259 @@ +// 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" + +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. + + // 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; + + 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. + + intptr_t readers; // Number of readers in mutex. + int priority; // Priority of thread (updated every so often). + + // When priority will next be read (cycles). + int64_t next_priority_read_cycles; + + // 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; + + 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 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; + + // Locks held; used during deadlock detection. + // Allocated in Synch_GetAllLocks() and freed in ReclaimThreadIdentity(). + SynchLocksHeld *all_locks; +}; + +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 { + char data[128]; + } 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. +// +// 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 direcly 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 direcly 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 direcly set +#else +#define ABSL_THREAD_IDENTITY_MODE_USE_CPP11 2 +#endif + +#ifdef ABSL_THREAD_IDENTITY_MODE +#error ABSL_THREAD_IDENTITY_MODE cannot be direcly 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 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. However, it is +// important for performance reasons in general that +// `CurrentThreadIdentityIfPresent` be inlined. This is not possible across a +// DLL boundary so, with DLLs, we opt to have the function not be inlined. Note +// that `CurrentThreadIdentityIfPresent` is declared above so we can exclude +// this entire inline definition when compiling as a DLL. +#if !defined(ABSL_BUILD_DLL) && !defined(ABSL_CONSUME_DLL) +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_ diff --git a/third_party/abseil-cpp/absl/base/internal/thread_identity_benchmark.cc b/third_party/abseil-cpp/absl/base/internal/thread_identity_benchmark.cc new file mode 100644 index 0000000000..0ae10f2b1e --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/thread_identity_benchmark.cc @@ -0,0 +1,38 @@ +// 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 diff --git a/third_party/abseil-cpp/absl/base/internal/thread_identity_test.cc b/third_party/abseil-cpp/absl/base/internal/thread_identity_test.cc new file mode 100644 index 0000000000..3685779ce8 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/thread_identity_test.cc @@ -0,0 +1,128 @@ +// 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/synchronization/internal/per_thread_sem.h" +#include "absl/synchronization/mutex.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { +namespace { + +// protects num_identities_reused +static absl::base_internal::SpinLock map_lock( + absl::base_internal::kLinkerInitialized); +static int num_identities_reused; + +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 = 400; + 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. + EXPECT_LT(kNumThreads, num_identities_reused); +} + +TEST(ThreadIdentityTest, ReusedThreadIdentityMutexTest) { + // This test repeatly 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 diff --git a/third_party/abseil-cpp/absl/base/internal/throw_delegate.cc b/third_party/abseil-cpp/absl/base/internal/throw_delegate.cc new file mode 100644 index 0000000000..c055f75d9d --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/throw_delegate.cc @@ -0,0 +1,108 @@ +// 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 { + +namespace { +template <typename T> +[[noreturn]] void Throw(const T& error) { +#ifdef ABSL_HAVE_EXCEPTIONS + throw error; +#else + ABSL_RAW_LOG(FATAL, "%s", error.what()); + std::abort(); +#endif +} +} // namespace + +void ThrowStdLogicError(const std::string& what_arg) { + Throw(std::logic_error(what_arg)); +} +void ThrowStdLogicError(const char* what_arg) { + Throw(std::logic_error(what_arg)); +} +void ThrowStdInvalidArgument(const std::string& what_arg) { + Throw(std::invalid_argument(what_arg)); +} +void ThrowStdInvalidArgument(const char* what_arg) { + Throw(std::invalid_argument(what_arg)); +} + +void ThrowStdDomainError(const std::string& what_arg) { + Throw(std::domain_error(what_arg)); +} +void ThrowStdDomainError(const char* what_arg) { + Throw(std::domain_error(what_arg)); +} + +void ThrowStdLengthError(const std::string& what_arg) { + Throw(std::length_error(what_arg)); +} +void ThrowStdLengthError(const char* what_arg) { + Throw(std::length_error(what_arg)); +} + +void ThrowStdOutOfRange(const std::string& what_arg) { + Throw(std::out_of_range(what_arg)); +} +void ThrowStdOutOfRange(const char* what_arg) { + Throw(std::out_of_range(what_arg)); +} + +void ThrowStdRuntimeError(const std::string& what_arg) { + Throw(std::runtime_error(what_arg)); +} +void ThrowStdRuntimeError(const char* what_arg) { + Throw(std::runtime_error(what_arg)); +} + +void ThrowStdRangeError(const std::string& what_arg) { + Throw(std::range_error(what_arg)); +} +void ThrowStdRangeError(const char* what_arg) { + Throw(std::range_error(what_arg)); +} + +void ThrowStdOverflowError(const std::string& what_arg) { + Throw(std::overflow_error(what_arg)); +} +void ThrowStdOverflowError(const char* what_arg) { + Throw(std::overflow_error(what_arg)); +} + +void ThrowStdUnderflowError(const std::string& what_arg) { + Throw(std::underflow_error(what_arg)); +} +void ThrowStdUnderflowError(const char* what_arg) { + Throw(std::underflow_error(what_arg)); +} + +void ThrowStdBadFunctionCall() { Throw(std::bad_function_call()); } + +void ThrowStdBadAlloc() { Throw(std::bad_alloc()); } + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/third_party/abseil-cpp/absl/base/internal/throw_delegate.h b/third_party/abseil-cpp/absl/base/internal/throw_delegate.h new file mode 100644 index 0000000000..075f527254 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/throw_delegate.h @@ -0,0 +1,75 @@ +// +// 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_ diff --git a/third_party/abseil-cpp/absl/base/internal/tsan_mutex_interface.h b/third_party/abseil-cpp/absl/base/internal/tsan_mutex_interface.h new file mode 100644 index 0000000000..2a510603bc --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/tsan_mutex_interface.h @@ -0,0 +1,66 @@ +// 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_ + +// 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(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_ diff --git a/third_party/abseil-cpp/absl/base/internal/unaligned_access.h b/third_party/abseil-cpp/absl/base/internal/unaligned_access.h new file mode 100644 index 0000000000..6be56c865b --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/unaligned_access.h @@ -0,0 +1,158 @@ +// +// 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" + +// 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) + +#if defined(ADDRESS_SANITIZER) || defined(THREAD_SANITIZER) ||\ + defined(MEMORY_SANITIZER) +// Consider we have an unaligned load/store of 4 bytes from address 0x...05. +// AddressSanitizer will treat it as a 3-byte access to the range 05:07 and +// will miss a bug if 08 is the first unaddressable byte. +// ThreadSanitizer will also treat this as a 3-byte access to 05:07 and will +// miss a race between this access and some other accesses to 08. +// MemorySanitizer will correctly propagate the shadow on unaligned stores +// and correctly report bugs on unaligned loads, but it may not properly +// update and report the origin of the uninitialized memory. +// For all three tools, replacing an unaligned access with a tool-specific +// callback solves the problem. + +// Make sure uint16_t/uint32_t/uint64_t are defined. +#include <stdint.h> + +extern "C" { +uint16_t __sanitizer_unaligned_load16(const void *p); +uint32_t __sanitizer_unaligned_load32(const void *p); +uint64_t __sanitizer_unaligned_load64(const void *p); +void __sanitizer_unaligned_store16(void *p, uint16_t v); +void __sanitizer_unaligned_store32(void *p, uint32_t v); +void __sanitizer_unaligned_store64(void *p, uint64_t v); +} // extern "C" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +inline uint16_t UnalignedLoad16(const void *p) { + return __sanitizer_unaligned_load16(p); +} + +inline uint32_t UnalignedLoad32(const void *p) { + return __sanitizer_unaligned_load32(p); +} + +inline uint64_t UnalignedLoad64(const void *p) { + return __sanitizer_unaligned_load64(p); +} + +inline void UnalignedStore16(void *p, uint16_t v) { + __sanitizer_unaligned_store16(p, v); +} + +inline void UnalignedStore32(void *p, uint32_t v) { + __sanitizer_unaligned_store32(p, v); +} + +inline void UnalignedStore64(void *p, uint64_t v) { + __sanitizer_unaligned_store64(p, 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)) + +#else + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace base_internal { + +inline uint16_t UnalignedLoad16(const void *p) { + uint16_t t; + memcpy(&t, p, sizeof t); + return t; +} + +inline uint32_t UnalignedLoad32(const void *p) { + uint32_t t; + memcpy(&t, p, sizeof t); + return t; +} + +inline uint64_t UnalignedLoad64(const void *p) { + uint64_t t; + memcpy(&t, p, sizeof t); + return t; +} + +inline void UnalignedStore16(void *p, uint16_t v) { memcpy(p, &v, sizeof v); } + +inline void UnalignedStore32(void *p, uint32_t v) { memcpy(p, &v, sizeof v); } + +inline void UnalignedStore64(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 + +#endif // defined(__cplusplus), end of unaligned API + +#endif // ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_ diff --git a/third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.cc b/third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.cc new file mode 100644 index 0000000000..f1e7bbef84 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.cc @@ -0,0 +1,140 @@ +// 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__) +#include <sys/sysctl.h> +#include <sys/types.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__) + +int64_t UnscaledCycleClock::Now() { + uint64_t low, high; + __asm__ volatile("rdtsc" : "=a"(low), "=d"(high)); + return (high << 32) | low; +} + +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( + "0:\n" + "mftbu %[hi32]\n" + "mftb %[lo32]\n" + "mftbu %[tmp]\n" + "cmpw %[tmp],%[hi32]\n" + "bne 0b\n" + : [ 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(__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__) + +// 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. +int64_t UnscaledCycleClock::Now() { + int64_t virtual_timer_value; + asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value)); + return virtual_timer_value; +} + +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 diff --git a/third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.h b/third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.h new file mode 100644 index 0000000000..cdce9bf8a8 --- /dev/null +++ b/third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.h @@ -0,0 +1,124 @@ +// 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 / whitelisted 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/port.h" + +// 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) +#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(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) || \ + (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 + +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(); + + // Whitelisted friends. + friend class base_internal::CycleClock; + friend class time_internal::UnscaledCycleClockWrapperForGetCurrentTime; + friend class base_internal::UnscaledCycleClockWrapperForInitializeFrequency; +}; + +} // namespace base_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_USE_UNSCALED_CYCLECLOCK + +#endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_ |