[cfe-dev] Clang C++0x extensions
Douglas Gregor
dgregor at apple.com
Thu Apr 28 09:36:16 PDT 2011
On Apr 28, 2011, at 9:23 AM, Fletcher, John P wrote:
> I don't see this error. I only see errors when I define -std=gnu++0x or -std=c++0x with clang 2.9.
>
> For me, Clang without the flags works, and also g++ with -std=gnu++0x
>
> It looks as though some of the errors are addressed in this patch file: libstdc++4.4-clang0x.patch
Right. That patch is necessary because libstdc++ 4.4 was written to a previous formulation of rvalue references (before we removed the ability of rvalue references to bind to lvalues), but Clang implements rvalue references based on the C++0x FDIS.
> but I have not seen anything there about type_info, the first of the errors I report.
It's a header-dependency bug in libstdc++-4.4, IIRC. GCC gets around it by (incorrectly) predefining std::type_info in the compiler. Just #include <typeinfo> in the appropriate place.
- Doug
> John
>
> ________________________________
> From: cfe-dev-bounces at cs.uiuc.edu [cfe-dev-bounces at cs.uiuc.edu] on behalf of İsmail Dönmez [ismail at namtrac.org]
> Sent: 28 April 2011 13:54
> To: Vassil Vassilev
> Cc: Fletcher, John P; cfe-dev Developers
> Subject: Re: [cfe-dev] Clang C++0x extensions
>
> This is a recent regression, see http://llvm.org/bugs/show_bug.cgi?id=9804
>
> ismail
>
> On Thu, Apr 28, 2011 at 2:43 PM, Vassil Vassilev <vasil.georgiev.vasilev at cern.ch<mailto:vasil.georgiev.vasilev at cern.ch>> wrote:
> Hi,
> Interesting... I don't think it is only for 0x... I have the same
> problem:
> uname -a
> Linux PCPHSFT79 2.6.32-31-generic #61-Ubuntu SMP Fri Apr 8 18:25:51 UTC
> 2011 x86_64 GNU/Linux
>
> cat clang_fails.cxx
> #include <string>
>
> extern "C" int printf(const char* fmt, ...);
>
> int main () {
> std::string a = "a";
> printf("%s\n", a.c_str());
> return 0;
> }
>
> ../Debug+Asserts/bin/clang clang_fails.cxx
> In file included from clang_fails.cxx:1:
> In file included from /usr/include/c++/4.4/string:41:
> In file included from /usr/include/c++/4.4/bits/char_traits.h:40:
> In file included from /usr/include/c++/4.4/bits/stl_algobase.h:65:
> /usr/include/c++/4.4/ext/numeric_traits.h:60:25: error: expected member
> name or ';' after declaration specifiers
> static const bool __is_signed = __glibcxx_signed(_Value);
> ~~~~~~~~~~~~~~~~~ ^
> /usr/include/c++/4.4/ext/numeric_traits.h:71:50: error: expected
> unqualified-id
> const bool __numeric_traits_integer<_Value>::__is_signed;
> ^
> /usr/include/c++/4.4/ext/numeric_traits.h:103:25: error: expected member
> name or ';' after declaration specifiers
> static const bool __is_signed = true;
> ~~~~~~~~~~~~~~~~~ ^
> /usr/include/c++/4.4/ext/numeric_traits.h:112:51: error: expected
> unqualified-id
> const bool __numeric_traits_floating<_Value>::__is_signed;
> ^
> In file included from clang_fails.cxx:1:
> In file included from /usr/include/c++/4.4/string:41:
> In file included from /usr/include/c++/4.4/bits/char_traits.h:40:
> /usr/include/c++/4.4/bits/stl_algobase.h:925:49: error: expected
> unqualified-id
> && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
> ^
> /usr/include/c++/4.4/bits/stl_algobase.h:930:45: error: non-type
> template argument of type 'const bool' is not an integral constant
> expression
> return std::__lexicographical_compare<__simple>::__lc(__first1,
> __last1,
> ^~~~~~~~
> 6 errors generated.
>
> I don't think this is expected. Is it?
>
> Vassil
>
> On 04/28/2011 01:52 PM, Fletcher, John P wrote:
>> Christopher
>>
>> Both -std=gnu++0x and -std=c++0x give errors in the GNU headers for gcc 4.4 (the default version of gcc on my ubuntu system)
>>
>> fletcher at fletcher-desktop:~/test$ gcc --version
>> gcc (Ubuntu 4.4.3-4ubuntu5) 4.4.3
>> Copyright (C) 2009 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions. There is NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>>
>> These errors may relate to c++0x things not yet implemented in Clang, or it could be that I need a different set of g++ headers. I cannot tell. Some problems are in<iostream> and some caused by clang/Basic/Version (clang 2.9)
>>
>> John
>>
>>
>> fletcher at fletcher-desktop:~/test$ make testcpp_cpp0x
>> /home/fletcher/LLVM/llvm/bin/clang++ -I/home/fletcher/LLVM/llvm/include -std=gnu++0x -DCLANG testcpp.cpp -otestcpp_cpp0x -L/home/fletcher/LLVM/llvm/lib -lclangBasic -lLLVMSupport -lpthread -ldl
>> In file included from testcpp.cpp:47:
>> In file included from /usr/include/c++/4.4/iostream:39:
>> In file included from /usr/include/c++/4.4/ostream:39:
>> In file included from /usr/include/c++/4.4/ios:39:
>> In file included from /usr/include/c++/4.4/exception:148:
>> /usr/include/c++/4.4/exception_ptr.h:143:13: error: unknown type name
>> 'type_info'
>> const type_info*
>> ^
>> In file included from testcpp.cpp:47:
>> In file included from /usr/include/c++/4.4/iostream:39:
>> In file included from /usr/include/c++/4.4/ostream:39:
>> In file included from /usr/include/c++/4.4/ios:40:
>> In file included from /usr/include/c++/4.4/bits/char_traits.h:40:
>> In file included from /usr/include/c++/4.4/bits/stl_algobase.h:66:
>> /usr/include/c++/4.4/bits/stl_pair.h:255:27: error: no matching function for
>> call to 'forward'
>> (std::forward<_T1>(__x), std::forward<_T2>(__y));
>> ^~~~~~~~~~~~~~~~~
>> In file included from testcpp.cpp:49:
>> In file included from /home/fletcher/LLVM/llvm/include/clang/Basic/Version.h:18:
>> /home/fletcher/LLVM/llvm/include/llvm/ADT/StringRef.h:363:16: note: in
>> instantiation of function template specialization 'std::make_pair<const
>> llvm::StringRef&, llvm::StringRef>' requested here
>> return std::make_pair(*this, StringRef());
>> ^
>> In file included from testcpp.cpp:47:
>> In file included from /usr/include/c++/4.4/iostream:39:
>> In file included from /usr/include/c++/4.4/ostream:39:
>> In file included from /usr/include/c++/4.4/ios:40:
>> In file included from /usr/include/c++/4.4/bits/char_traits.h:40:
>> In file included from /usr/include/c++/4.4/bits/stl_algobase.h:66:
>> In file included from /usr/include/c++/4.4/bits/stl_pair.h:60:
>> /usr/include/c++/4.4/bits/move.h:51:5: note: candidate function [with _Tp =
>> llvm::StringRef] not viable: no known conversion from 'llvm::StringRef' to
>> 'typename std::identity<StringRef>::type&&' (aka 'llvm::StringRef&&')
>> for 1st argument
>> forward(typename std::identity<_Tp>::type&& __t)
>> ^
>> /usr/include/c++/4.4/bits/move.h:57:14: error: binding of reference to type
>> 'typename std::remove_reference<StringRef&>::type'
>> (aka 'llvm::StringRef') to a value of type 'llvm::StringRef' drops
>> qualifiers
>> { return __t; }
>> ^~~
>> In file included from testcpp.cpp:47:
>> In file included from /usr/include/c++/4.4/iostream:39:
>> In file included from /usr/include/c++/4.4/ostream:39:
>> In file included from /usr/include/c++/4.4/ios:40:
>> In file included from /usr/include/c++/4.4/bits/char_traits.h:40:
>> In file included from /usr/include/c++/4.4/bits/stl_algobase.h:66:
>> /usr/include/c++/4.4/bits/stl_pair.h:93:15: note: in instantiation of function
>> template specialization 'std::move<llvm::StringRef&>' requested here
>> : first(std::move(__p.first)),
>> ^
>> In file included from testcpp.cpp:49:
>> In file included from /home/fletcher/LLVM/llvm/include/clang/Basic/Version.h:18:
>> /home/fletcher/LLVM/llvm/include/llvm/ADT/StringRef.h:363:16: note: in
>> instantiation of member function 'std::pair<llvm::StringRef,
>> llvm::StringRef>::pair' requested here
>> return std::make_pair(*this, StringRef());
>> ^
>> In file included from testcpp.cpp:47:
>> In file included from /usr/include/c++/4.4/iostream:39:
>> In file included from /usr/include/c++/4.4/ostream:39:
>> In file included from /usr/include/c++/4.4/ios:40:
>> In file included from /usr/include/c++/4.4/bits/char_traits.h:40:
>> In file included from /usr/include/c++/4.4/bits/stl_algobase.h:66:
>> /usr/include/c++/4.4/bits/stl_pair.h:255:3: error: no matching function for call
>> to 'forward'
>> (std::forward<_T1>(__x), std::forward<_T2>(__y));
>> ^~~~~~~~~~~~~~~~~
>> In file included from testcpp.cpp:49:
>> In file included from /home/fletcher/LLVM/llvm/include/clang/Basic/Version.h:18:
>> /home/fletcher/LLVM/llvm/include/llvm/ADT/StringRef.h:364:14: note: in
>> instantiation of function template specialization
>> 'std::make_pair<llvm::StringRef, llvm::StringRef>' requested here
>> return std::make_pair(slice(0, Idx), slice(Idx+1, npos));
>> ^
>> In file included from testcpp.cpp:47:
>> In file included from /usr/include/c++/4.4/iostream:39:
>> In file included from /usr/include/c++/4.4/ostream:39:
>> In file included from /usr/include/c++/4.4/ios:40:
>> In file included from /usr/include/c++/4.4/bits/char_traits.h:40:
>> In file included from /usr/include/c++/4.4/bits/stl_algobase.h:66:
>> In file included from /usr/include/c++/4.4/bits/stl_pair.h:60:
>> /usr/include/c++/4.4/bits/move.h:51:5: note: candidate function [with _Tp =
>> llvm::StringRef] not viable: no known conversion from 'llvm::StringRef' to
>> 'typename std::identity<StringRef>::type&&' (aka 'llvm::StringRef&&')
>> for 1st argument
>> forward(typename std::identity<_Tp>::type&& __t)
>> ^
>> 4 errors generated.
>> make: *** [testcpp_cpp0x] Error 1
>>
>> ________________________________________
>> From: cfe-dev-bounces at cs.uiuc.edu<mailto:cfe-dev-bounces at cs.uiuc.edu> [cfe-dev-bounces at cs.uiuc.edu<mailto:cfe-dev-bounces at cs.uiuc.edu>] on behalf of Christopher Jefferson [chris at bubblescope.net<mailto:chris at bubblescope.net>]
>> Sent: 27 April 2011 08:49
>> To: Fletcher, John P
>> Cc: cfe-dev Developers
>> Subject: Re: [cfe-dev] Clang C++0x extensions
>>
>> On 26 Apr 2011, at 17:59, Fletcher, John P wrote:
>>
>>> Is there a specific command option to enable Clang C++0x extensions? I have been looking through the manual and cannot find this.
>> You probably want -std=gnu++0x.
>>
>> You can use -std=c++0x, but that disables gnu extensions. The default flag is -std=gnu++03, and quite a bit of code (including last time I checked the standard header<cmath> on mac os x) won't compile in c++03 or c++0x mode.
>>
>> Chris
>> _______________________________________________
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