diff options
| -rw-r--r-- | absl/hash/BUILD.bazel | 2 | ||||
| -rw-r--r-- | absl/hash/hash_test.cc | 8 | ||||
| -rw-r--r-- | absl/synchronization/internal/waiter.cc | 57 | ||||
| -rw-r--r-- | absl/synchronization/internal/waiter.h | 20 |
4 files changed, 70 insertions, 17 deletions
diff --git a/absl/hash/BUILD.bazel b/absl/hash/BUILD.bazel index 8c2daf703bcd..e1e6eae8516d 100644 --- a/absl/hash/BUILD.bazel +++ b/absl/hash/BUILD.bazel @@ -35,10 +35,10 @@ cc_library( copts = ABSL_DEFAULT_COPTS, linkopts = ABSL_DEFAULT_LINKOPTS, deps = [ - ":city", "//absl/base:core_headers", "//absl/base:endian", "//absl/container:fixed_array", + "//absl/hash:city", "//absl/meta:type_traits", "//absl/numeric:int128", "//absl/strings", diff --git a/absl/hash/hash_test.cc b/absl/hash/hash_test.cc index af9593850a4b..92c64ad509d8 100644 --- a/absl/hash/hash_test.cc +++ b/absl/hash/hash_test.cc @@ -425,10 +425,10 @@ TEST(HashValueTest, Maps) { } template <typename T, typename = void> -struct IsHashCallble : std::false_type {}; +struct IsHashCallable : std::false_type {}; template <typename T> -struct IsHashCallble<T, absl::void_t<decltype(std::declval<absl::Hash<T>>()( +struct IsHashCallable<T, absl::void_t<decltype(std::declval<absl::Hash<T>>()( std::declval<const T&>()))>> : std::true_type {}; template <typename T, typename = void> @@ -445,7 +445,7 @@ TEST(IsHashableTest, ValidHash) { EXPECT_TRUE(std::is_move_constructible<absl::Hash<int>>::value); EXPECT_TRUE(absl::is_copy_assignable<absl::Hash<int>>::value); EXPECT_TRUE(absl::is_move_assignable<absl::Hash<int>>::value); - EXPECT_TRUE(IsHashCallble<int>::value); + EXPECT_TRUE(IsHashCallable<int>::value); EXPECT_TRUE(IsAggregateInitializable<absl::Hash<int>>::value); } @@ -458,7 +458,7 @@ TEST(IsHashableTest, PoisonHash) { EXPECT_FALSE(std::is_move_constructible<absl::Hash<X>>::value); EXPECT_FALSE(absl::is_copy_assignable<absl::Hash<X>>::value); EXPECT_FALSE(absl::is_move_assignable<absl::Hash<X>>::value); - EXPECT_FALSE(IsHashCallble<X>::value); + EXPECT_FALSE(IsHashCallable<X>::value); EXPECT_FALSE(IsAggregateInitializable<absl::Hash<X>>::value); } #endif // ABSL_META_INTERNAL_STD_HASH_SFINAE_FRIENDLY_ diff --git a/absl/synchronization/internal/waiter.cc b/absl/synchronization/internal/waiter.cc index 74b0965018c5..f17ea56fdda3 100644 --- a/absl/synchronization/internal/waiter.cc +++ b/absl/synchronization/internal/waiter.cc @@ -40,6 +40,8 @@ #include <atomic> #include <cassert> #include <cstdint> +#include <new> +#include <type_traits> #include "absl/base/internal/raw_logging.h" #include "absl/base/internal/thread_identity.h" @@ -328,6 +330,43 @@ void Waiter::Poke() { #elif ABSL_WAITER_MODE == ABSL_WAITER_MODE_WIN32 +class Waiter::WinHelper { + public: + static SRWLOCK *GetLock(Waiter *w) { + return reinterpret_cast<SRWLOCK *>(&w->mu_storage_); + } + + static CONDITION_VARIABLE *GetCond(Waiter *w) { + return reinterpret_cast<CONDITION_VARIABLE *>(&w->cv_storage_); + } + + static_assert(sizeof(SRWLOCK) == sizeof(Waiter::SRWLockStorage), + "SRWLockStorage does not have the same size as SRWLOCK"); + static_assert( + alignof(SRWLOCK) == alignof(Waiter::SRWLockStorage), + "SRWLockStorage does not have the same alignment as SRWLOCK"); + + static_assert(sizeof(CONDITION_VARIABLE) == + sizeof(Waiter::ConditionVariableStorage), + "ABSL_CONDITION_VARIABLE_STORAGE does not have the same size " + "as CONDITION_VARIABLE"); + static_assert(alignof(CONDITION_VARIABLE) == + alignof(Waiter::ConditionVariableStorage), + "ConditionVariableStorage does not have the same " + "alignment as CONDITION_VARIABLE"); + + // The SRWLOCK and CONDITION_VARIABLE types must be trivially constuctible + // and destructible because we never call their constructors or destructors. + static_assert(std::is_trivially_constructible<SRWLOCK>::value, + "The SRWLOCK type must be trivially constructible"); + static_assert(std::is_trivially_constructible<CONDITION_VARIABLE>::value, + "The CONDITION_VARIABLE type must be trivially constructible"); + static_assert(std::is_trivially_destructible<SRWLOCK>::value, + "The SRWLOCK type must be trivially destructible"); + static_assert(std::is_trivially_destructible<CONDITION_VARIABLE>::value, + "The CONDITION_VARIABLE type must be trivially destructible"); +}; + class LockHolder { public: explicit LockHolder(SRWLOCK* mu) : mu_(mu) { @@ -346,14 +385,19 @@ class LockHolder { }; void Waiter::Init() { - InitializeSRWLock(&mu_); - InitializeConditionVariable(&cv_); + auto *mu = ::new (static_cast<void *>(&mu_storage_)) SRWLOCK; + auto *cv = ::new (static_cast<void *>(&cv_storage_)) CONDITION_VARIABLE; + InitializeSRWLock(mu); + InitializeConditionVariable(cv); waiter_count_.store(0, std::memory_order_relaxed); wakeup_count_.store(0, std::memory_order_relaxed); } bool Waiter::Wait(KernelTimeout t) { - LockHolder h(&mu_); + SRWLOCK *mu = WinHelper::GetLock(this); + CONDITION_VARIABLE *cv = WinHelper::GetCond(this); + + LockHolder h(mu); waiter_count_.fetch_add(1, std::memory_order_relaxed); // Loop until we find a wakeup to consume or timeout. @@ -371,8 +415,7 @@ bool Waiter::Wait(KernelTimeout t) { } // No wakeups available, time to wait. - if (!SleepConditionVariableSRW( - &cv_, &mu_, t.InMillisecondsFromNow(), 0)) { + if (!SleepConditionVariableSRW(cv, mu, t.InMillisecondsFromNow(), 0)) { // GetLastError() returns a Win32 DWORD, but we assign to // unsigned long to simplify the ABSL_RAW_LOG case below. The uniform // initialization guarantees this is not a narrowing conversion. @@ -399,11 +442,11 @@ void Waiter::Poke() { return; } // Potentially a waker. Take the lock and check again. - LockHolder h(&mu_); + LockHolder h(WinHelper::GetLock(this)); if (waiter_count_.load(std::memory_order_relaxed) == 0) { return; } - WakeConditionVariable(&cv_); + WakeConditionVariable(WinHelper::GetCond(this)); } #else diff --git a/absl/synchronization/internal/waiter.h b/absl/synchronization/internal/waiter.h index 66b4bebfb532..a3e3124e4417 100644 --- a/absl/synchronization/internal/waiter.h +++ b/absl/synchronization/internal/waiter.h @@ -18,9 +18,7 @@ #include "absl/base/config.h" -#ifdef _WIN32 -#include <windows.h> -#else +#ifndef _WIN32 #include <pthread.h> #endif @@ -123,8 +121,20 @@ class Waiter { // primivitives. We are using SRWLOCK and CONDITION_VARIABLE // because they don't require a destructor to release system // resources. - SRWLOCK mu_; - CONDITION_VARIABLE cv_; + // + // However, we can't include Windows.h in our headers, so we use aligned + // storage buffers to define the storage. + using SRWLockStorage = + typename std::aligned_storage<sizeof(void*), alignof(void*)>::type; + using ConditionVariableStorage = + typename std::aligned_storage<sizeof(void*), alignof(void*)>::type; + + // WinHelper - Used to define utilities for accessing the lock and + // condition variable storage once the types are complete. + class WinHelper; + + SRWLockStorage mu_storage_; + ConditionVariableStorage cv_storage_; std::atomic<int> waiter_count_; std::atomic<int> wakeup_count_; |