[PATCH] D45639: [Driver] Support default libc++ library location on Darwin

[Petr Hosek via Phabricator via cfe-commits]

phosek added a comment.

I think we just ran into one such issue. We're using our own Clang that's usually following tip-of-tree and we recently switched to C++17, but that started failing on our macOS 10.12 bots with:

  Undefined symbols for architecture x86_64:
    "operator delete(void*, std::align_val_t)", referenced from:
        _main in main.cpp.o
        std::__1::__vector_base<std::__1::unique_ptr<fidl::SourceFile, std::__1::default_delete<fidl::SourceFile> >, std::__1::allocator<std::__1::unique_ptr<fidl::SourceFile, std::__1::default_delete<fidl::SourceFile> > > >::~__vector_base() in main.cpp.o
        std::__1::__vector_base<std::__1::unique_ptr<fidl::raw::UnionDeclaration, std::__1::default_delete<fidl::raw::UnionDeclaration> >, std::__1::allocator<std::__1::unique_ptr<fidl::raw::UnionDeclaration, std::__1::default_delete<fidl::raw::UnionDeclaration> > > >::~__vector_base() in main.cpp.o
        std::__1::__vector_base<std::__1::unique_ptr<fidl::raw::UnionMember, std::__1::default_delete<fidl::raw::UnionMember> >, std::__1::allocator<std::__1::unique_ptr<fidl::raw::UnionMember, std::__1::default_delete<fidl::raw::UnionMember> > > >::~__vector_base() in main.cpp.o
        std::__1::__vector_base<std::__1::unique_ptr<fidl::raw::Attribute, std::__1::default_delete<fidl::raw::Attribute> >, std::__1::allocator<std::__1::unique_ptr<fidl::raw::Attribute, std::__1::default_delete<fidl::raw::Attribute> > > >::~__vector_base() in main.cpp.o
        std::__1::__vector_base<std::__1::unique_ptr<fidl::raw::StructDeclaration, std::__1::default_delete<fidl::raw::StructDeclaration> >, std::__1::allocator<std::__1::unique_ptr<fidl::raw::StructDeclaration, std::__1::default_delete<fidl::raw::StructDeclaration> > > >::~__vector_base() in main.cpp.o
        std::__1::__vector_base<std::__1::unique_ptr<fidl::raw::StructMember, std::__1::default_delete<fidl::raw::StructMember> >, std::__1::allocator<std::__1::unique_ptr<fidl::raw::StructMember, std::__1::default_delete<fidl::raw::StructMember> > > >::~__vector_base() in main.cpp.o
        ...
    "operator new(unsigned long, std::align_val_t)", referenced from:
        std::__1::enable_if<__is_forward_iterator<char*>::value, void>::type std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__init<char*>(char*, char*) in main.cpp.o
        std::__1::unique_ptr<std::__1::__tree_node<std::__1::__value_type<(anonymous namespace)::Behavior, std::__1::basic_fstream<char, std::__1::char_traits<char> > >, void*>, std::__1::__tree_node_destructor<std::__1::allocator<std::__1::__tree_node<std::__1::__value_type<(anonymous namespace)::Behavior, std::__1::basic_fstream<char, std::__1::char_traits<char> > >, void*> > > > std::__1::__tree<std::__1::__value_type<(anonymous namespace)::Behavior, std::__1::basic_fstream<char, std::__1::char_traits<char> > >, std::__1::__map_value_compare<(anonymous namespace)::Behavior, std::__1::__value_type<(anonymous namespace)::Behavior, std::__1::basic_fstream<char, std::__1::char_traits<char> > >, std::__1::less<(anonymous namespace)::Behavior>, true>, std::__1::allocator<std::__1::__value_type<(anonymous namespace)::Behavior, std::__1::basic_fstream<char, std::__1::char_traits<char> > > > >::__construct_node<(anonymous namespace)::Behavior, std::__1::basic_fstream<char, std::__1::char_traits<char> > >((anonymous namespace)::Behavior&&, std::__1::basic_fstream<char, std::__1::char_traits<char> >&&) in main.cpp.o
        std::__1::__split_buffer<fidl::SourceManager, std::__1::allocator<fidl::SourceManager>&>::__split_buffer(unsigned long, unsigned long, std::__1::allocator<fidl::SourceManager>&) in main.cpp.o
        std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >::__vallocate(unsigned long) in main.cpp.o
        std::__1::unique_ptr<std::__1::__tree_node<std::__1::__value_type<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::unique_ptr<fidl::flat::Library, std::__1::default_delete<fidl::flat::Library> > >, void*>, std::__1::__tree_node_destructor<std::__1::allocator<std::__1::__tree_node<std::__1::__value_type<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::unique_ptr<fidl::flat::Library, std::__1::default_delete<fidl::flat::Library> > >, void*> > > > std::__1::__tree<std::__1::__value_type<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::unique_ptr<fidl::flat::Library, std::__1::default_delete<fidl::flat::Library> > >, std::__1::__map_value_compare<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::__value_type<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::unique_ptr<fidl::flat::Library, std::__1::default_delete<fidl::flat::Library> > >, std::__1::less<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> > >, true>, std::__1::allocator<std::__1::__value_type<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::unique_ptr<fidl::flat::Library, std::__1::default_delete<fidl::flat::Library> > > > >::__construct_node<std::__1::pair<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::unique_ptr<fidl::flat::Library, std::__1::default_delete<fidl::flat::Library> > > >(std::__1::pair<std::__1::vector<fidl::StringView, std::__1::allocator<fidl::StringView> >, std::__1::unique_ptr<fidl::flat::Library, std::__1::default_delete<fidl::flat::Library> > >&&) in main.cpp.o
        std::__1::enable_if<__is_forward_iterator<char const*>::value, void>::type std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__init<char const*>(char const*, char const*) in libfidl.a(c_generator.cpp.o)
        std::__1::__split_buffer<unsigned int, std::__1::allocator<unsigned int>&>::__split_buffer(unsigned long, unsigned long, std::__1::allocator<unsigned int>&) in libfidl.a(c_generator.cpp.o)
        ...
  ld: symbol(s) not found for architecture x86_64

AFAICT this is because `/usr/lib/libc++.dylib` doesn't yet support C++17, but the headers that are part of Clang toolchain do. When we force Clang to use libc++ that's part of the toolchain by manually setting the necessary `-L`/`-l` flag resolves the issue. I don't know if this is an expected behavior, but I'd really appreciate some response on this.


Repository:
  rC Clang

https://reviews.llvm.org/D45639