forked from OSchip/llvm-project
8c2bf45da9
This patch further decouples libc++ from pthread, allowing libc++ to be built against other threading systems. There are two main use cases: - Building libc++ against a thread library other than pthreads. - Building libc++ with an "external" thread API, allowing a separate library to provide the implementation of that API. The two use cases are quite similar, the second one being sligtly more de-coupled than the first. The cmake option LIBCXX_HAS_EXTERNAL_THREAD_API enables both kinds of builds. One needs to place an <__external_threading> header file containing an implementation of the "libc++ thread API" declared in the <__threading_support> header. For the second use case, the implementation of the libc++ thread API can delegate to a custom "external" thread API where the implementation of this external API is provided in a seperate library. This mechanism allows toolchain vendors to distribute a build of libc++ with a custom thread-porting-layer API (which is the "external" API above), platform vendors (recipients of the toolchain/libc++) are then required to provide their implementation of this API to be linked with (end-user) C++ programs. Note that the second use case still requires establishing the basic types that get passed between the external thread library and the libc++ library (e.g. __libcpp_mutex_t). These cannot be opaque pointer types (libc++ sources won't compile otherwise). It should also be noted that the second use case can have a slight performance penalty; as all the thread constructs need to cross a library boundary through an additional function call. When the header <__external_threading> is omitted, libc++ is built with the "libc++ thread API" (declared in <__threading_support>) as the "external" thread API (basic types are pthread based). An implementation (pthread based) of this API is provided in test/support/external_threads.cpp, which is built into a separate DSO and linked in when running the libc++ test suite. A test run therefore demonstrates the second use case (less the intermediate custom API). Differential revision: https://reviews.llvm.org/D21968 Reviewers: bcraig, compnerd, EricWF, mclow.lists llvm-svn: 281179 |
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| .. | ||
| test.support | ||
| Counter.h | ||
| DefaultOnly.h | ||
| MoveOnly.h | ||
| allocators.h | ||
| any_helpers.h | ||
| archetypes.hpp | ||
| archetypes.ipp | ||
| asan_testing.h | ||
| assert_checkpoint.h | ||
| cmpxchg_loop.h | ||
| constexpr_char_traits.hpp | ||
| container_test_types.h | ||
| count_new.hpp | ||
| counting_predicates.hpp | ||
| disable_missing_braces_warning.h | ||
| experimental_any_helpers.h | ||
| external_threads.cpp | ||
| filesystem_dynamic_test_helper.py | ||
| filesystem_test_helper.hpp | ||
| hexfloat.h | ||
| is_transparent.h | ||
| min_allocator.h | ||
| nasty_containers.hpp | ||
| nasty_macros.hpp | ||
| nothing_to_do.pass.cpp | ||
| platform_support.h | ||
| private_constructor.hpp | ||
| propagate_const_helpers.h | ||
| rapid-cxx-test.hpp | ||
| test_allocator.h | ||
| test_convertible.hpp | ||
| test_iterators.h | ||
| test_macros.h | ||
| test_memory_resource.hpp | ||
| test_throw.h | ||
| tracked_value.h | ||
| type_id.h | ||
| user_defined_integral.hpp | ||
| uses_alloc_types.hpp | ||