<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div><br></div><div><br>On 14 Feb 2013, at 5:25 PM, Saleem Abdulrasool <<a href="mailto:compnerd@compnerd.org">compnerd@compnerd.org</a>> wrote:<br><br></div><blockquote type="cite"><div><p><br>
On Feb 14, 2013 6:39 AM, "Alexey Samsonov" <<a href="mailto:samsonov@google.com">samsonov@google.com</a>> wrote:<br>
><br>
><br>
> On Thu, Feb 7, 2013 at 7:47 PM, Howard Hinnant <<a href="mailto:hhinnant@apple.com">hhinnant@apple.com</a>> wrote:<br>
>><br>
>> On Feb 7, 2013, at 6:17 AM, Alexey Samsonov <<a href="mailto:samsonov@google.com">samsonov@google.com</a>> wrote:<br>
>><br>
>> > Hi!<br>
>> ><br>
>> > I'm trying to build libcxx on Linux (Ubuntu Precise) using the following command:<br>
>> ><br>
>> > cmake -DLIBCXX_CXX_ABI=libsupc++ '-DLIBCXX_LIBSUPCXX_INCLUDE_PATHS=/usr/include/c++/4.6;/usr/include/c++/4.6/x86_64-linux-gnu/.;' -DLIBCXX_ENABLE_EXCEPTIONS=OFF -DLIBCXX_ENABLE_SHARED=OFF -DLIBCXX_ENABLE_RTTI=OFF -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/tmp.boBpS5zFqt/libcxx_inst /tmp/tmp.boBpS5zFqt/libcxx<br>
>> ><br>
>> > and I want the result to be "hermetic" in the sense that resulting static library libc++.a doesn't reference undefined symbols from std::<br>
>> > However, I see the following problems:<br>
>> ><br>
>> > (libc++.a.new.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/new.cpp:function std::bad_alloc::~bad_alloc(): error: undefined reference to 'std::exception::~exception()'<br>
>> > (libc++.a.new.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/new.cpp:function std::bad_array_new_length::~bad_array_new_length(): error: undefined reference to 'std::exception::~exception()'<br>
>> > (libc++.a.new.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/new.cpp:function std::bad_array_new_length::~bad_array_new_length(): error: undefined reference to 'std::exception::~exception()'<br>
>> > (libc++.a.ios.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/ios.cpp:function std::__1::basic_ostream<char, std::__1::char_traits<char> >::flush(): error: undefined reference to 'std::uncaught_exception()'<br>
>> > (libc++.a.ios.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/ios.cpp:function std::__1::basic_ostream<wchar_t, std::__1::char_traits<wchar_t> >::flush(): error: undefined reference to 'std::uncaught_exception()'<br>
>> > (libc++.a.ios.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/ios.cpp:function std::__1::basic_ostream<char, std::__1::char_traits<char> >::sentry::~sentry(): error: undefined reference to 'std::uncaught_exception()'<br>
>> > (libc++.a.ios.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/ios.cpp:function std::__1::basic_ostream<char, std::__1::char_traits<char> >::sentry::~sentry(): error: undefined reference to 'std::uncaught_exception()'<br>
>> > (libc++.a.memory.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/memory.cpp:function std::__1::bad_weak_ptr::~bad_weak_ptr(): error: undefined reference to 'std::exception::~exception()'<br>
>> > (libc++.a.memory.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/memory.cpp:function vtable for std::__1::__shared_weak_count: error: undefined reference to 'std::__1::__shared_weak_count::__get_deleter(std::type_info const&) const'<br>
>> > (libc++.a.thread.cpp.o):/tmp/tmp.boBpS5zFqt/libcxx/src/thread.cpp:function std::__1::thread::~thread(): error: undefined reference to 'std::terminate()'<br>
>> ><br>
>> > What is the correct way to for that? I have the patch (attached) that works for me, but I'm not really sure it's correct<br>
>> > (especially the first part).<br>
>><br>
>> Yeah, we tried this once:<br>
>><br>
>> > --- include/memory (revision 173248)<br>
>> > +++ include/memory (working copy)<br>
>> > @@ -3629,10 +3629,9 @@<br>
>> > long use_count() const _NOEXCEPT {return __shared_count::use_count();}<br>
>> > __shared_weak_count* lock() _NOEXCEPT;<br>
>> ><br>
>> > - // purposefully not protected with #ifndef _LIBCPP_NO_RTTI because doing so<br>
>> > - // breaks ABI for those clients who need to compile their projects with<br>
>> > - // -fno-rtti and yet link against a libc++.dylib compiled without -fno-rtti.<br>
>> > +#ifndef _LIBCPP_NO_RTTI<br>
>> > virtual const void* __get_deleter(const type_info&) const _NOEXCEPT;<br>
>> > +#endif _LIBCPP_NO_RTTI<br>
>><br>
>> and as the comments indicate, got bitten by it, at least on Apple platforms.<br>
>><br>
>> Way forward: Perhaps you could #ifdef it a little more in such a way that it isn't going to trigger except for someone trying to do exactly what you are doing: Build a static lib on linux with rtti and exceptions off. Or perhaps slightly more general: Build a static lib with rtti and exceptions off.<br>
><br>
><br>
> Yes, I can add some #ifdefs here. But I also wonder about the second part of the patch: <br>
> I have __GLIBCXX__ defined because of commit:<br>
><br>
> r173164 Saleem Abdulrasool: Ensure that __GLIBCXX__ is defined when building with libsupc++.<br>
><br>
> and, as a result, I don't get definitions of terminate(), uncaught_exception(), exception>::~exception() and exception::what() in the resulting libc++ library,<br>
> yet these functions are referenced from it.</p>
<p>Those functions are provided by libsupc++, and redefining them results in conflicts. If you are building a static libc++, you would still need to link against the low level provider, or you need to merge a static copy of libsupc++ into your resulting libc++.a.<br></p></div></blockquote><div>You should also bear in mind that libsupc++ does not implement the dependent EH API, which is an extension that libc++ needs (due to the API for the ABI library not encapsulating sufficient functionality to be able to properly share a runtime library between standard libraries). For now you'd probably be better off with libc++abi or libcxxrt if you want to use anything that requires exception_ptr, uncaught_exception or global terminate handlers.</div><blockquote type="cite"><div><p>
</p>
<p>> -- <br>
> Alexey Samsonov, MSK</p>
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