replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

[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 1ac403bd14, which had to be reverted in
64a9c944fc 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
This commit is contained in:
Louis Dionne 2020-04-22 11:15:05 -04:00
parent f3e667bf86
commit e58660750e
2 changed files with 6 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
libcxx/CMakeLists.txt
View File

@ -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)

12
libcxx/src/barrier.cpp
View File

@ -26,21 +26,15 @@ public:
} __tickets[64];
};
ptrdiff_t& __expected;
unique_ptr<char[]> __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<char[]>(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)