| ================ |
| PSTL integration |
| ================ |
| |
| The PSTL (or Parallel STL) project is quite complex in its current form and does not provide everything that libc++ |
| requires, for example ``_LIBCPP_HIDE_FROM_ABI`` or similar annotations and including granularized headers. Furthermore, |
| the PSTL provides various layers of indirection that make sense in a generic implementation of the parallel algorithms, |
| but are unnecessarily complex in the context of a single standard library implementation. Because of these drawbacks, we |
| decided to adopt a modified PSTL in libc++. Specifically, the goals of the modified PSTL are |
| |
| - No ``<__pstl_algorithm>`` and similar glue headers -- instead, the implementation files are included directly in |
| ``<algorithm>`` and friends. |
| - No ``<pstl/internal/algorithm_impl.h>`` and ``<pstl/internal/algorithm_fwd.h>`` headers and friends -- these contain |
| the implementation and forward declarations for internal functions respectively. The implementation lives inside |
| ``<__algorithm/pstl_any_of.h>`` and friends, and the forward declarations are not needed inside libc++. |
| - No ``<pstl/internal/glue_algorithm_defs.h>`` and ``<pstl/internal/glue_algorithm_impl.h>`` headers and friends -- |
| these contain the public API. It lives inside ``<__algorithm/pstl_any_of.h>`` and friends instead. |
| - The headers implementing backends are kept with as few changes as possible to make it easier to keep the backends in |
| sync with the backends from the original PSTL. |
| - The configuration headers ``__pstl_config_site.in`` and ``pstl_config.h`` are removed, and any required configuration |
| is done inside ``__config_site.in`` and ``__config`` respectively. |
| - libc++-style tests for the public PSTL API |
