Linking issue using thread_local std::vector.

[AC_Simon33]

Hi,

i've encountered a weird issue when I tried to use a thread_local std::vector as a member variable inside a templated class/struct. The code compiles with icl but the linker says that the object file is basically corrupted (see pictures).

This is the minimal example that reproduces the issue on my machines:

#include <vector>

template<typename TA>
struct A {
  static thread_local std::vector<int> s;
};

template<typename TA>
thread_local std::vector<int> A<TA>::s;

template struct A<double>;

int main() {
  return 0;
}

This works in gcc, clang, icc, msvc (all versions that support thread_local). Through a bit of testing I found out that the issue vanishes if:

  - the struct is not templated.

  - the variable is a global variable outside of the class 

  - std::vector is replace by std::array (all other containers fail though)

Additional information:

OS Name: Microsoft Windows 10 Enterprise LTSC (64bit)

OS Version: 10.0.17763 Build 17763

Processor: Intel(R) Xeon(R) Gold 5218 CPU

Compiler Version: 19.0.5.281 Build 20190815 and 19.1.3.311 Build 20201010_000000

VS Version: 2017 (Linker Version 14.16.27045.0) and 2019 (Linker Version 14.28.29335.0)

Compile command: icl test.cpp

The dumbin.exe output is attached.

Best regards,

Simon

[VidyalathaB_Intel · Accepted solution]

Hi,

Thanks for reaching out to us.

Could you please try compiling the code using icx compiler on windows as it is working fine without giving any such errors.

icx is intel's oneAPI compiler which comes with oneAPI toolkits.

You can download it from the below links

oneAPI Base toolkit:

https://software.intel.com/content/www/us/en/develop/tools/oneapi/base-toolkit/download.html

oneAPI HPC toolkit:

https://software.intel.com/content/www/us/en/develop/tools/oneapi/hpc-toolkit/download.html

We suggest you to try using latest oneAPI compilers and let us know if you face any issues.

Regards,

Vidya.

[AC_Simon33]

Hi, 

Thanks for the reply.

icx works indeed, thanks for the suggestion.

For my icl pipeline I'll use __declspec(thread) for now since that seems to work:

#ifdef __ICL
  #define MY_THREAD_LOCAL __declspec(thread)
#else
  #define MY_THREAD_LOCAL thread_local
#endif

Best regards,

Simon

[VidyalathaB_Intel]

Hi,

>>since that seems to work

Glad to know that your issue is resolved.

As your issue has beed resolved could you please confirm whether we can close this thread from our.

Regards,

Vidya.

[AC_Simon33]

I’m ok with using that workaround. If icl is replaced by icx in the future anyway then there is probably no need for a fix.

Best regards,
Simon

[VidyalathaB_Intel]

Hi,

Thanks for accepting our solution.

As the issue is resolved we are closing this thread from our end.

Please raise a new thread if you have any other queries.

Regards,

Vidya.