[libc++] Integrate the PSTL into libc++

Summary:
This commit allows specifying LIBCXX_ENABLE_PARALLEL_ALGORITHMS when
configuring libc++ in CMake. When that option is enabled, libc++ will
assume that the PSTL can be found somewhere on the CMake module path,
and it will provide the C++17 parallel algorithms based on the PSTL
(that is assumed to be available).

The commit also adds support for running the PSTL tests as part of
the libc++ test suite.

Reviewers: rodgert, EricWF

Subscribers: mgorny, christof, jkorous, dexonsmith, libcxx-commits, mclow.lists, EricWF

Tags: #libc

Differential Revision: https://reviews.llvm.org/D60480

llvm-svn: 366593

1 files changed, 7 insertions, 0 deletions

diff --git a/libcxx/utils/libcxx/test/config.py b/libcxx/utils/libcxx/test/config.py
index e263e9db750..e694ea14793 100644
--- a/libcxx/utils/libcxx/test/config.py
+++ b/libcxx/utils/libcxx/test/config.py
@@ -580,6 +580,13 @@ class Configuration(object):
         support_path = os.path.join(self.libcxx_src_root, 'test/support')
         self.cxx.compile_flags += ['-I' + support_path]
 
+        # Add includes for the PSTL headers
+        pstl_root = self.get_lit_conf('pstl_root')
+        if pstl_root is not None:
+            self.cxx.compile_flags += ['-I' + os.path.join(pstl_root, 'include')]
+            self.cxx.compile_flags += ['-I' + os.path.join(pstl_root, 'test')]
+            self.config.available_features.add('parallel-algorithms')
+
         # FIXME(EricWF): variant_size.pass.cpp requires a slightly larger
         # template depth with older Clang versions.
         self.cxx.addFlagIfSupported('-ftemplate-depth=270')