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
andpstl_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