[Rcpp-devel] Patch for using Rcpp with Clang + libc++ AND Intel icpc C++11

[Yan Zhou]

Dear Dirk,

In addition to my last email which provides a path for clang++ with libc++, I updated the patch to also fix problems with intel icpc in C++11 mode.

In the RcppCommon.h, there is comments says that Intel ICPC does not support C++11 or TR1. That is not entirely true. Intel compiler does not come with its own standard library. On Linux and Mac OS X it use the libstdc++ come with the system. On Windows it may use others.  The current test has a problem when an Intel C++ compiler is used in C++11 mode. In that case, headers like sugar/sets.h test the C++11 macro and conclude it shall define SET to std::unordered_set. However, C++11 <unordered_set> is not included. So a compiler error happens.

In general, I found Rcpp does not work with compilers in C++11 mode. The new path, in addition to the own test Clang with libc++, also test the followings,
1. If Intel compiler is used, test is it is used with libstdc++. If it is not, then we undef HAS_TR1_... etc. To test if libstdc++ is used, we need to at least include one standard library header before the testing, so I included <cmath>, which shall be harmless
2. After trying to include <tr1/unodered_map> etc, we also test if we are using C++11. If it is, then test if we are using libstdc++ (either gcc, clang, intel etc). If it is case, and the libstdc++ is recent enough, we include <unordered_map> and <unordered_set>. Otherwise, if we are using C++11 in Clang with libc++, we also included <unodered_map> etc.

After this patch, Rcpp shall work seamlessly with GCC, Intel and Clang, in both C++98 and C++11 modes.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: RcppCommon.h.diff
Type: application/octet-stream
Size: 1622 bytes
Desc: not available
URL: <http://lists.r-forge.r-project.org/pipermail/rcpp-devel/attachments/20121201/e1498ba0/attachment.obj>
-------------- next part --------------


Best,

Yan Zhou



On Dec 1, 2012, at 12:12 PM, Yan Zhou <zhouyan at me.com> wrote:

> Hi Dirk,
> 
> Rcpp cannot be compiled with clang++ with libc++, even clang++  provides very good standard conforming in both C++98 and C++11 mode, and libc++ provides 100% C++98/11 features. The problems is Rcpp's use of TR1 instead of C++11, and does not perform some compiler checks properly. I made a small patch to the include/RcppCommon.h header, which makes Rcpp works with Clang++ and libc++ in C++11 mode.
> 
> To summary the change, when macro __clang__ is defined, the header use clang's __has_include to check if <tr1/unordered_map> and <tr1/unordered_set> is present, if not, it undef HAS_TR1_UNORDERED_MAP etc. In addition, if __has_include<unordered_map> is tested to be true while HAS_TR1_... etc are not true, the C++11 header is included. So  headers like sugar/sets.h can use C++11 header instead of TR1, since they already test __cplusplus >= 201103L.
> 
> With this patch, nothing already works will be broken. This patch only affects clang++ with libc++ situation. Using clang++ with libstdc++ the situation will be exactly the same as before.
> 
> At the end of the email is the path, it is also attached as a diff file
> 
> Best,
> 
> Yan Zhou
> <RcppCommon.h.diff>
> 
> --- Rcpp/inst/include/RcppCommon.h	2012-11-23 01:07:34.000000000 +0000
> +++ ../Downloads/Rcpp/inst/include/RcppCommon.h	2012-12-01 11:46:48.000000000 +0000
> @@ -107,6 +107,20 @@
> //     #endif
> // #endif
> 
> +#ifdef __clang__
> +    #if !__has_include(<tr1/unordered_map>)
> +        #undef HAS_TR1
> +        #undef HAS_TR1_UNORDERED_MAP
> +    #endif
> +    #if !__has_include(<tr1/unordered_set>)
> +        #undef HAS_TR1
> +        #undef HAS_TR1_UNORDERED_SET
> +    #endif
> +    #if !__has_feature(cxx_variadic_templates)
> +        #undef HAS_VARIADIC_TEMPLATES
> +    #endif
> +#endif
> +
> #ifdef __INTEL_COMPILER
>     // This is based on an email by Alexey Stukalov who tested 
>     // Intel Compiler 12.0 and states that is does support Cxx0x 
> @@ -149,6 +163,15 @@
> #include <tr1/unordered_set>
> #endif
> 
> +#ifdef __clang__
> +    #if !defined(HAS_TR1_UNORDERED_MAP) && __has_include(<unordered_map>)
> +    #include <unordered_map>
> +    #endif
> +    #if !defined(HAS_TR1_UNORDERED_SET) && __has_include(<unordered_set>)
> +    #include <unordered_set>
> +    #endif
> +#endif
> +
> std::string demangle( const std::string& name) ;
> #define DEMANGLE(__TYPE__) demangle( typeid(__TYPE__).name() ).c_str() 
> 
> 
> _______________________________________________
> Rcpp-devel mailing list
> Rcpp-devel at lists.r-forge.r-project.org
> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel