From e58660750e76fa36c62d6b515da291d0ffa53e2b Mon Sep 17 00:00:00 2001 From: Louis Dionne Date: Wed, 22 Apr 2020 11:15:05 -0400 Subject: [PATCH] [libc++] Build the dylib with C++17 to allow aligned new/delete This allows simplifying the implementation of barriers. This is a re-commit of 1ac403bd145d, which had to be reverted in 64a9c944fc45 because the minimum CMake version wasn't high enough. Now that we've upgraded, we can do this. Differential Revision: https://reviews.llvm.org/D75243 --- libcxx/CMakeLists.txt | 6 +++--- libcxx/src/barrier.cpp | 12 +++--------- 2 files changed, 6 insertions(+), 12 deletions(-) diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt index a5adccf..bf2ae67 100644 --- a/libcxx/CMakeLists.txt +++ b/libcxx/CMakeLists.txt @@ -519,10 +519,10 @@ remove_flags(-Wno-pedantic -pedantic-errors -pedantic) # Required flags ============================================================== function(cxx_add_basic_build_flags target) - # Require C++14 for all targets. C++14 is needed to ensure constant - # initialization for certain globals (ex global memory resources). + # Require C++17 for all targets. C++17 is needed to use aligned allocation + # in the dylib. set_target_properties(${target} PROPERTIES - CXX_STANDARD 14 + CXX_STANDARD 17 CXX_STANDARD_REQUIRED YES CXX_EXTENSIONS NO) diff --git a/libcxx/src/barrier.cpp b/libcxx/src/barrier.cpp index c5e33cb..9ee4769 100644 --- a/libcxx/src/barrier.cpp +++ b/libcxx/src/barrier.cpp @@ -26,21 +26,15 @@ public: } __tickets[64]; }; - ptrdiff_t& __expected; - unique_ptr __state_allocation; - __state_t* __state; + ptrdiff_t& __expected; + unique_ptr<__state_t[]> __state; _LIBCPP_HIDDEN __barrier_algorithm_base(ptrdiff_t& __expected) : __expected(__expected) { size_t const __count = (__expected + 1) >> 1; - size_t const __size = sizeof(__state_t) * __count; - size_t __allocation_size = __size + alignof(__state_t); - __state_allocation = unique_ptr(new char[__allocation_size]); - void* __allocation = __state_allocation.get(); - void* const __state_ = align(alignof(__state_t), __size, __allocation, __allocation_size); - __state = new (__state_) __barrier_algorithm_base::__state_t[__count]; + __state = unique_ptr<__state_t[]>(new __state_t[__count]); } _LIBCPP_HIDDEN bool __arrive(__barrier_phase_t __old_phase) -- 2.7.4