FindTBB.cmake: only search TBB in Config mode if version >= 2019 update 5

[janetournois]

Summary of Changes

Avoid the following error when TBB was already found a few lines earlier, by adding a condition NOT TBB_FOUND before find_package(TBB) :

CMake Error at C:/dev/tbb2019_20181203oss_win/tbb2019_20181203oss/cmake/TBBConfig.cmake:83 (add_library):
  add_library cannot create imported target "TBB::tbb" because another target
  with the same name already exists.

Release Management

• Affected package(s): Polyhedron (demo)
• License and copyright ownership: unchanged

[lrineau]

I think we should fix #5687, instead. That is a bug from TBB before version 2019 update 5, and we have an easy workaround: #5693 (comment).

[janetournois]

Be careful : CMake is fixed but the demo does not compile yet with this fix

[lrineau]

Be careful : CMake is fixed but the demo does not compile yet with this fix

The compilation error is:

.../Mesh_3/include/CGAL/Mesh_complex_3_in_triangulation_3.h:105:3: error: use of deleted function 'tbb::detail::d1::tbb_hash_compare<std::pair<CGAL::internal::CC_iterator<CGAL::Compact_container<CGAL::Mesh_vertex_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, std::tuple<int, int, int, int>, int, CGAL::Regular_triangulation_vertex_base_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Triangulation_ds_vertex_base_3<CGAL::Triangulation_data_structure_3<CGAL::Mesh_vertex_generator_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, std::tuple<int, int, int, int>, int, CGAL::Regular_triangulation_vertex_base_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Triangulation_ds_vertex_base_3<void> > >, CGAL::Triangulation_cell_base_with_info_3<int, CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Compact_mesh_cell_base_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Polyhedral_mesh_domain_with_features_3<CGAL::Epick, CGAL::Surface_mesh<CGAL::Point_3<CGAL::Epick> >, CGAL::Default, int> > >, CGAL::Sequential_tag> > > >, CGAL::Default, CGAL::Default, CGAL::Default>, false>, CGAL::internal::CC_iterator<CGAL::Compact_container<CGAL::Mesh_vertex_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, std::tuple<int, int, int, int>, int, CGAL::Regular_triangulation_vertex_base_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Triangulation_ds_vertex_base_3<CGAL::Triangulation_data_structure_3<CGAL::Mesh_vertex_generator_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, std::tuple<int, int, int, int>, int, CGAL::Regular_triangulation_vertex_base_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Triangulation_ds_vertex_base_3<void> > >, CGAL::Triangulation_cell_base_with_info_3<int, CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Compact_mesh_cell_base_3<CGAL::Robust_weighted_circumcenter_filtered_traits_3<CGAL::Mesh_3::Robust_intersection_traits_3_new<CGAL::Epick> >, CGAL::Polyhedral_mesh_domain_with_features_3<CGAL::Epick, CGAL::Surface_mesh<CGAL::Point_3<CGAL::Epick> >, CGAL::Default, int> > >, CGAL::Sequential_tag> > > >, CGAL::Default, CGAL::Default, CGAL::Default>, false> > >::~tbb_hash_compare()'

That is because we have

  typedef tbb::concurrent_hash_map<Pair_of_vertices, int> Edge_facet_counter;

where Pair_of_vertices is a std::pair of Vertex_handle. For TBB before oneAPI, we define an overload of tbb_hasher, that can be found by ADL:

cgal/Mesh_3/include/CGAL/Mesh_3/Mesh_complex_3_in_triangulation_3_base.h

Line 60 in daf70db

template < class DSC, bool Const >

But oneAPI-TBB has switched to the use of std::hash.

In think we should pass explicitly a HashCompare to the concurrent_hash_map. That API is the same for TBB and oneAPI-TBB.

In TBB, the default argument for HashCompare was:

template<typename Key>
struct tbb_hash_compare {
    static size_t hash( const Key& a ) { return tbb_hasher(a); }
    static bool equal( const Key& a, const Key& b ) { return a == b; }
};

(see the ADL call to tbb_hasher).

In oneAPI-TBB, that is:

template <typename Key>
class tbb_hash_compare {
public:
    std::size_t hash( const Key& a ) const { return my_hash_func(a); }
    bool equal( const Key& a, const Key& b ) const { return my_key_equal(a, b); }
private:
    std::hash<Key> my_hash_func;
    std::equal_to<Key> my_key_equal;
};

(see the use of std::hash).

[maxGimeno]

Successfully tested in https://cgal.geometryfactory.com/CGAL/testsuite/results-5.3-Ic-138.shtml