From b69c7d880caddfc25bf348dbcfe9d45fdd8bc6e6 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Fri, 21 Feb 2020 12:51:36 -0800 Subject: Export of internal Abseil changes -- 00f5301405423005d9129935c05f20155536cc1a by CJ Johnson : Removes usage of std::aligned_storage from Abseil implementation details PiperOrigin-RevId: 296492301 -- fc11d15f91764612fba080669d2381dc181df52b by Abseil Team : Fix absl::bind_front documentation. PiperOrigin-RevId: 296482945 -- 0164c595c129c46bf21ae74eba5399a1da5f140b by Gennadiy Rozental : Automated g4 rollback of changelist 296320700. PiperOrigin-RevId: 296439968 -- 1eb295700758ca0894d872b2de7c675b4ad679af by Abseil Team : Removes duplicate comments. PiperOrigin-RevId: 296433214 -- c30c01caae02d2fa4ef783d988de6bebb9757c39 by Derek Mauro : Merge GitHub #621: Add RISCV support to GetProgramCounter() Fixes #621 PiperOrigin-RevId: 296351174 -- 95d4498167596fd7543e025bdfe9a8da9e2ca3c8 by Abseil Team : Automated g4 rollback of changelist 296320700. PiperOrigin-RevId: 296348701 -- b193f0543e0cec54dddb2ed51f45dc489c8d06d5 by Gennadiy Rozental : Change TryParse interface to return managed value. In addition introduce companion StoreValue routine which consumes pointer to source value and stores the value inside of FlagImpl. In a follow up CL we will change StoreValue implementation to behave differently depending on "value storage kind". We also rename default_src_ to default_value_. PiperOrigin-RevId: 296320700 -- 57e942b485d12912a0a8d0d0b35fa2a62847020f by Derek Mauro : Merge GitHub #622 * Add missing #ifdef conditionals for ABSL_HAVE_VDSO_SUPPORT PiperOrigin-RevId: 296272830 GitOrigin-RevId: 00f5301405423005d9129935c05f20155536cc1a Change-Id: I1b05eeaf1280f95fb0a2c5f3654995a87c792893 --- absl/synchronization/internal/mutex_nonprod.inc | 4 +-- absl/synchronization/internal/waiter.cc | 34 ++++++++++++------------- absl/synchronization/internal/waiter.h | 13 +++------- 3 files changed, 22 insertions(+), 29 deletions(-) (limited to 'absl/synchronization') diff --git a/absl/synchronization/internal/mutex_nonprod.inc b/absl/synchronization/internal/mutex_nonprod.inc index 85dae0f..a1502e7 100644 --- a/absl/synchronization/internal/mutex_nonprod.inc +++ b/absl/synchronization/internal/mutex_nonprod.inc @@ -252,8 +252,8 @@ class SynchronizationStorage { absl::once_flag once_; - // An aligned space for T. - typename std::aligned_storage::type space_; + // An aligned space for the T. + alignas(T) unsigned char space_[sizeof(T)]; }; } // namespace synchronization_internal diff --git a/absl/synchronization/internal/waiter.cc b/absl/synchronization/internal/waiter.cc index ddd6081..2949f5a 100644 --- a/absl/synchronization/internal/waiter.cc +++ b/absl/synchronization/internal/waiter.cc @@ -368,31 +368,29 @@ class Waiter::WinHelper { return reinterpret_cast(&w->cv_storage_); } - static_assert(sizeof(SRWLOCK) == sizeof(Waiter::SRWLockStorage), - "SRWLockStorage does not have the same size as SRWLOCK"); + static_assert(sizeof(SRWLOCK) == sizeof(void *), + "`mu_storage_` does not have the same size as SRWLOCK"); + static_assert(alignof(SRWLOCK) == alignof(void *), + "`mu_storage_` does not have the same alignment as SRWLOCK"); + + static_assert(sizeof(CONDITION_VARIABLE) == sizeof(void *), + "`ABSL_CONDITION_VARIABLE_STORAGE` does not have the same size " + "as `CONDITION_VARIABLE`"); 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"); + alignof(CONDITION_VARIABLE) == alignof(void *), + "`cv_storage_` does not have the same alignment as `CONDITION_VARIABLE`"); // The SRWLOCK and CONDITION_VARIABLE types must be trivially constructible // and destructible because we never call their constructors or destructors. static_assert(std::is_trivially_constructible::value, - "The SRWLOCK type must be trivially constructible"); - static_assert(std::is_trivially_constructible::value, - "The CONDITION_VARIABLE type must be trivially constructible"); + "The `SRWLOCK` type must be trivially constructible"); + static_assert( + std::is_trivially_constructible::value, + "The `CONDITION_VARIABLE` type must be trivially constructible"); static_assert(std::is_trivially_destructible::value, - "The SRWLOCK type must be trivially destructible"); + "The `SRWLOCK` type must be trivially destructible"); static_assert(std::is_trivially_destructible::value, - "The CONDITION_VARIABLE type must be trivially destructible"); + "The `CONDITION_VARIABLE` type must be trivially destructible"); }; class LockHolder { diff --git a/absl/synchronization/internal/waiter.h b/absl/synchronization/internal/waiter.h index 5af5c28..a6e6d4c 100644 --- a/absl/synchronization/internal/waiter.h +++ b/absl/synchronization/internal/waiter.h @@ -133,13 +133,6 @@ class Waiter { std::atomic wakeups_; #elif ABSL_WAITER_MODE == ABSL_WAITER_MODE_WIN32 - // We can't include Windows.h in our headers, so we use aligned storage - // buffers to define the storage of SRWLOCK and CONDITION_VARIABLE. - using SRWLockStorage = - typename std::aligned_storage::type; - using ConditionVariableStorage = - typename std::aligned_storage::type; - // WinHelper - Used to define utilities for accessing the lock and // condition variable storage once the types are complete. class WinHelper; @@ -147,8 +140,10 @@ class Waiter { // REQUIRES: WinHelper::GetLock(this) must be held. void InternalCondVarPoke(); - SRWLockStorage mu_storage_; - ConditionVariableStorage cv_storage_; + // We can't include Windows.h in our headers, so we use aligned charachter + // buffers to define the storage of SRWLOCK and CONDITION_VARIABLE. + alignas(void*) unsigned char mu_storage_[sizeof(void*)]; + alignas(void*) unsigned char cv_storage_[sizeof(void*)]; int waiter_count_; int wakeup_count_; -- cgit v1.2.3