[cfe-dev] Build libc++ against musl-libc.

[邓尧]

On Sat, Sep 21, 2013 at 9:40 AM, Howard Hinnant <hhinnant at apple.com> wrote:

> Thank you for your efforts to port libc++ to musl-libc.
>

> Unfortunately your patch below breaks other platforms.  You will need to
> isolate your changes such that they only impact your platform.
>

This patch is just a proof of concept. When I get most of the test cases
passed, I'll rewrite the whole patch, and do necessary isolation.


>
> Howard
>
> On Sep 17, 2013, at 2:25 AM, 邓尧 <torshie at gmail.com> wrote:
>
> > Hi,
> > I'm trying to build libc++ against musl-libc ( www.musl-libc.org ),
> another linux C library. I have successfully built a musl-libc based C
> toolchain, a freestanding C++ compiler, and some C++ runtime libraries like
> libcxxrt, libunwind, I even succeeded in building libc++ against musl-libc,
> but a simple hello-world program won't run.
> >
> > the following code would throw a bad_cast exception:
> >
> > #include <locale>
> > #include <iostream>
> > #include <cstdio>
> >
> > using namespace std;
> >
> > int main() {
> >     locale loc("C");
> >     //cout.imbue(loc);  // If this line is added, the whole program runs
> well.
> >     cout << "hello" << endl;
> >     return 0;
> > }
> >
> > This is the call stack of the thrown exception:
> > #6  0x00000000004ce2d9 in __cxa_throw ()
> > #7  0x0000000000422a40 in std::__1::locale::__imp::use_facet(long) const
> ()
> >     at /home/hoolala/workspace/bootcxx/out/libcxx/src/locale.cpp:439
> > #8  0x0000000000423379 in
> std::__1::locale::use_facet(std::__1::locale::id&) const ()
> >     at /home/hoolala/workspace/bootcxx/out/libcxx/src/locale.cpp:581
> > #9  0x00000000004005ad in std::__1::basic_ostream<char,
> std::__1::char_traits<char> >& std::__1::operator<<
> <std::__1::char_traits<char> >(std::__1::basic_ostream<char,
> std::__1::char_traits<char> >&, char const*) ()
> >     at
> /home/hoolala/workspace/bootcxx/out/sysroot/usr/include/c++/v1/__locale:174
> > #10 0x000000000040035a in main () at loc.cpp:12
> >
> > I applied a simple patch to the original libc++ code:
> >
> > Index: include/__locale
> > ===================================================================
> > --- include/__locale    (revision 190843)
> > +++ include/__locale    (working copy)
> > @@ -376,7 +376,7 @@
> >      static const mask xdigit = _ISXDIGIT;
> >      static const mask blank  = _ISBLANK;
> >  #else  // __GLIBC__ || _WIN32 || __APPLE__ || __FreeBSD__ || EMSCRIPTEN
> || __sun__
> > -    typedef unsigned long mask;
> > +    typedef unsigned short mask;
> >      static const mask space  = 1<<0;
> >      static const mask print  = 1<<1;
> >      static const mask cntrl  = 1<<2;
> > Index: include/locale
> > ===================================================================
> > --- include/locale    (revision 190843)
> > +++ include/locale    (working copy)
> > @@ -829,7 +829,7 @@
> >          typename remove_reference<decltype(errno)>::type __save_errno =
> errno;
> >          errno = 0;
> >          char *__p2;
> > -        long long __ll = strtoll_l(__a, &__p2, __base,
> _LIBCPP_GET_C_LOCALE);
> > +        long long __ll = strtoll(__a, &__p2, __base);
> >          typename remove_reference<decltype(errno)>::type
> __current_errno = errno;
> >          if (__current_errno == 0)
> >              errno = __save_errno;
> > @@ -869,7 +869,7 @@
> >          typename remove_reference<decltype(errno)>::type __save_errno =
> errno;
> >          errno = 0;
> >          char *__p2;
> > -        unsigned long long __ll = strtoull_l(__a, &__p2, __base,
> _LIBCPP_GET_C_LOCALE);
> > +        unsigned long long __ll = strtoull(__a, &__p2, __base);
> >          typename remove_reference<decltype(errno)>::type
> __current_errno = errno;
> >          if (__current_errno == 0)
> >              errno = __save_errno;
> > @@ -899,7 +899,7 @@
> >          typename remove_reference<decltype(errno)>::type __save_errno =
> errno;
> >          errno = 0;
> >          char *__p2;
> > -        long double __ld = strtold_l(__a, &__p2, _LIBCPP_GET_C_LOCALE);
> > +        long double __ld = strtold(__a, &__p2);
> >          typename remove_reference<decltype(errno)>::type
> __current_errno = errno;
> >          if (__current_errno == 0)
> >              errno = __save_errno;
> > Index: src/locale.cpp
> > ===================================================================
> > --- src/locale.cpp    (revision 190843)
> > +++ src/locale.cpp    (working copy)
> > @@ -1005,6 +1005,8 @@
> >  extern "C" const int ** __ctype_toupper_loc();
> >  #endif
> >
> > +extern "C" const unsigned short ** __ctype_b_loc();
> > +
> >  const ctype<char>::mask*
> >  ctype<char>::classic_table()  _NOEXCEPT
> >  {
> > @@ -1027,10 +1029,11 @@
> >  #else
> >      // Platform not supported: abort so the person doing the port knows
> what to
> >      // fix
> > -# warning  ctype<char>::classic_table() is not implemented
> > -    printf("ctype<char>::classic_table() is not implemented\n");
> > -    abort();
> > -    return NULL;
> > +//# warning  ctype<char>::classic_table() is not implemented
> > +    //printf("ctype<char>::classic_table() is not implemented\n");
> > +    //abort();
> > +    //return NULL;
> > +    return *__ctype_b_loc();
> >  #endif
> >  }
> >
> > Did I miss anything in the patch ?
> >
> > Thanks
> > Yao
> >
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>
>
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