Error compiling pipeline.h with Clang

[Blue_Sky_Studios]

I ran into this error compiling an application with TBB 4.1.4 and Clang++ 3.3:

In file included from [snip]/tbb/tbb.h:67:
[snip]/tbb/pipeline.h:348:74: error: no template named
      'is_trivially_copyable' in namespace 'std'; did you mean 'tbb_trivially_copyable'?
template<typename T> struct tbb_trivially_copyable { enum { value = std::is_trivially_copyable<T>::value }; };
                                                                    ~~~~~^~~~~~~~~~~~~~~~~~~~~
                                                                         tbb_trivially_copyable
/netDISKS/master/netmt/LINUX_INTF14C/cgi/intel_tbb/4.1.4/Include/libtbb/tbb/pipeline.h:348:29: note: 'tbb_trivially_copyable' declared here
template<typename T> struct tbb_trivially_copyable { enum { value = std::is_trivially_copyable<T>::value }; };
                            ^
/netDISKS/master/netmt/LINUX_INTF14C/cgi/intel_tbb/4.1.4/Include/libtbb/tbb/pipeline.h:348:100: error: no member named 'value' in
      'tbb_trivially_copyable<T>'
template<typename T> struct tbb_trivially_copyable { enum { value = std::is_trivially_copyable<T>::value }; };
                                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^

I fixed the header with this:

@@ -342,7 +342,7 @@
 template<> struct tbb_trivially_copyable <float> { enum { value = !tbb_large_object<float>::value }; };
 template<> struct tbb_trivially_copyable <double> { enum { value = !tbb_large_object<double>::value }; };
 #else
-#if __GNUC__==4 && __GNUC_MINOR__>=4 && __GXX_EXPERIMENTAL_CXX0X__
+#if (__GNUC__==4 && __GNUC_MINOR__>=4 && __GXX_EXPERIMENTAL_CXX0X__) || __clang_major__ >= 3
 template<typename T> struct tbb_trivially_copyable { enum { value = std::has_trivial_copy_constructor<T>::value }; };
 #else
 template<typename T> struct tbb_trivially_copyable { enum { value = std::is_trivially_copyable<T>::value }; };

I have no idea what version of Clang++ is appropriate to detect the change from is_trivially_copyable to has_trivial_copy_constructor.  I found that tbb_config.h sets TBB_IMPLEMENT_CPP0X to 0 for Clang++ in line 251.  Perhaps similar logic is needed in pipeline.h.

[RafSchietekat]

The source code states that it "cannot use SFINAE in current compilers", but I suppose that "type traits" was meant instead: this requires SFINAE (a given since C++03 if I am not mistaken), but SFINAE is insufficient to accurately implement all type traits.

And, considering that even a multi-megabyte object could be trivially copyable, why compare with the size of a pointer? It's not even relevant because tbb_trivially_copyable is only used in is_large_object, which has a separate test for tbb_large_object, but which should also be renamed to reflect what it actually means.

TBB_IMPLEMENT_CPP0X seems to have several problems: it means the opposite of what you would suspect, but then seems to reverse that again with regard to <thread> and <condition_variable>, and may be incomplete. What's needed here is a test for <type_traits> availability and functionality. I would recommend adding __TBB_CPP11_TYPE_TRAITS_PRESENT to tbb_config.h, and either using that instead of TBB_IMPLEMENT_CPP0X in pipeline.h or using part of my recent contribution incorporating a more complete implementation of is_trivially_copyable. Note that __has_include(<type_traits>) was not enough the last time I tried this on OS X, but I have not explored this further, including whether it depends on the use of libc++, which is not the default with TBB even with compiler=clang.

[Anton_P_Intel]

hadsell, could you please specify compiler switches used?  

[Anton_P_Intel]

Raf, could you please elaborate that problems did you faced on OS X with  __has_include(<type_traits>) ? IIRC gcc 4.1 should have type_traits under tr1 folder and probably Clang should not detect it via __has_include.

[Blue_Sky_Studios]

For an optimized compile:

-march=core2 -msse4.1 -m64 -std=c++0x -fPIC -pthread -gcc-toolchain /opt/gcc-4.7.2 -Wno-logical-op-parentheses -Wno-shift-op-parentheses -O2

[RafSchietekat]

In the code I submitted yesterday, if I enable the test for __has_include(<type_traits>) at tbb_config.h:114, I get a compiler crash, even if I add "-std=c++11 -stdlib=libc++" (without the quotes) to CPLUS_FLAGS in macos.clang.inc. From inside Xcode in a simple test program I can set such a switch, #include <type_traits>, and evaluate std::is_trivially_copyable<float>(), but not with TBB from the command line. I haven't tried to use TBB from inside Xcode yet.

[Blue_Sky_Studios]

Today I started to upgrade from TBB 4.1 update 4 to 4.2 update 3.  I found the same problem with pipeline.h.  I had to apply the same fix for compiling with Clang++:

diff -u -r1.1 -r1.2
--- pipeline.h    28 Apr 2014 21:27:20 -0000    1.1
+++ pipeline.h    28 Apr 2014 22:35:54 -0000    1.2
@@ -342,7 +342,7 @@
 template<> struct tbb_trivially_copyable <float> { enum { value = !tbb_large_object<float>::value }; };
template<> struct tbb_trivially_copyable <double> { enum { value = !tbb_large_object<double>::value }; };
#else
-#if __GNUC__==4 && __GNUC_MINOR__>=4 && __GXX_EXPERIMENTAL_CXX0X__
+#if (__GNUC__==4 && __GNUC_MINOR__>=4 && __GXX_EXPERIMENTAL_CXX0X__) || __clang_major__ >= 3
template<typename T> struct tbb_trivially_copyable { enum { value = std::has_trivial_copy_constructor<T>::value }; };
#else
template<typename T> struct tbb_trivially_copyable { enum { value = std::is_trivially_copyable<T>::value }; };

[Alexey-Kukanov]

The bug is fixed in recently released version 4.3.