1*5c6be1d4SNikolas Klauser================ 2*5c6be1d4SNikolas KlauserPSTL integration 3*5c6be1d4SNikolas Klauser================ 4*5c6be1d4SNikolas Klauser 5*5c6be1d4SNikolas KlauserThe PSTL (or Parallel STL) project is quite complex in its current form and does not provide everything that libc++ 6*5c6be1d4SNikolas Klauserrequires, for example ``_LIBCPP_HIDE_FROM_ABI`` or similar annotations and including granularized headers. Furthermore, 7*5c6be1d4SNikolas Klauserthe PSTL provides various layers of indirection that make sense in a generic implementation of the parallel algorithms, 8*5c6be1d4SNikolas Klauserbut are unnecessarily complex in the context of a single standard library implementation. Because of these drawbacks, we 9*5c6be1d4SNikolas Klauserdecided to adopt a modified PSTL in libc++. Specifically, the goals of the modified PSTL are 10*5c6be1d4SNikolas Klauser 11*5c6be1d4SNikolas Klauser- No ``<__pstl_algorithm>`` and similar glue headers -- instead, the implementation files are included directly in 12*5c6be1d4SNikolas Klauser ``<algorithm>`` and friends. 13*5c6be1d4SNikolas Klauser- No ``<pstl/internal/algorithm_impl.h>`` and ``<pstl/internal/algorithm_fwd.h>`` headers and friends -- these contain 14*5c6be1d4SNikolas Klauser the implementation and forward declarations for internal functions respectively. The implementation lives inside 15*5c6be1d4SNikolas Klauser ``<__algorithm/pstl_any_of.h>`` and friends, and the forward declarations are not needed inside libc++. 16*5c6be1d4SNikolas Klauser- No ``<pstl/internal/glue_algorithm_defs.h>`` and ``<pstl/internal/glue_algorithm_impl.h>`` headers and friends -- 17*5c6be1d4SNikolas Klauser these contain the public API. It lives inside ``<__algorithm/pstl_any_of.h>`` and friends instead. 18*5c6be1d4SNikolas Klauser- The headers implementing backends are kept with as few changes as possible to make it easier to keep the backends in 19*5c6be1d4SNikolas Klauser sync with the backends from the original PSTL. 20*5c6be1d4SNikolas Klauser- The configuration headers ``__pstl_config_site.in`` and ``pstl_config.h`` are removed, and any required configuration 21*5c6be1d4SNikolas Klauser is done inside ``__config_site.in`` and ``__config`` respectively. 22*5c6be1d4SNikolas Klauser- libc++-style tests for the public PSTL API 23