Errors trying to build simple header+loader binary

[juliohm]

I am trying to cross-compile OpenCL for different applications in Julia, but the build is giving this error as if the CMAKE_CXX_STANDARD at the top level was ignored. Can you please take a look at the following build record?

https://pastebin.com/V5CCYxDP

You can see that the C99 standard is being used for some reason in the build.

[MathiasMagnus]

@juliohm Thanks for reporting this.

The issue isn't that the build is using C99 for some reason. The issue is that it isn't using C99, but uses the default C standard, which I guess is C89. It was a conscious decision that the OpenCL ecosystem going forward won't support 30 year old language standards. Unfortunately our OpenCL-SDK CI coverage isn't quite the same breadth yet as the rest of the ecosystem, and this failure is triggered in the utility libraries.

We'll discuss this issue, my educated guess is that the utility libraries will target C11 and onward, maybe C99. We'd need to improve our testing in CI to make sure such fiascos don't happen in the future.

I also saw that you build a full blows SDK, however my guess is that Julia is only using the OpenCL headers and libraries. If you can pass extra arguments to CMake, I'd highly suggest adding -D OPENCL_SDK_BUILD_SAMPLES=OFF to reduce build times significantly.

[juliohm]

Thank you @MathiasMagnus I will try to build it again with the proposed option. Will also try -D CMAKE_C_STANDARD=11 in the command line to see if the error goes away following suggestions from Julia community members.

[MathiasMagnus]

You beat me to, I was just about to amend my message with the same idea. Let me know how it turns out.

[juliohm]

Ok, the option CMAKE_C_STANDARD=11 fixed that error, but now I have another error:

In file included from /workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Utils.hpp:6:0,
                 from /workspace/srcdir/OpenCL-SDK/lib/src/Utils/Utils.cpp:2:
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:25:41: error: ‘std::integer_sequence’ has not been declared
                                    std::integer_sequence<int, Is...>)
                                         ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:25:57: error: expected ‘,’ or ‘...’ before ‘<’ token
                                    std::integer_sequence<int, Is...>)
                                                         ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp: In function ‘void cl::util::detail::for_each_in_tuple(const std::tuple<_Elements ...>&, F&&)’:
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:38:17: error: ‘make_integer_sequence’ is not a member of ‘std’
                 std::make_integer_sequence<int, sizeof...(Ts)>());
                 ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:38:44: error: expected primary-expression before ‘int’
                 std::make_integer_sequence<int, sizeof...(Ts)>());
                                            ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:38:64: error: expected primary-expression before ‘)’ token
                 std::make_integer_sequence<int, sizeof...(Ts)>());
                                                                ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp: At global scope:
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:45:57: error: ‘std::index_sequence’ has not been declared
             auto transform_tuple(Tuple&& t, F&& f, std::index_sequence<Is...>)
                                                         ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:45:71: error: expected ‘,’ or ‘...’ before ‘<’ token
             auto transform_tuple(Tuple&& t, F&& f, std::index_sequence<Is...>)
                                                                       ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp: In function ‘auto cl::util::detail::transform_tuple(const std::tuple<_Elements ...>&, F&&)’:
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:55:17: error: ‘make_index_sequence’ is not a member of ‘std’
                 std::make_index_sequence<sizeof...(Args)>{});
                 ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:55:58: error: expected primary-expression before ‘{’ token
                 std::make_index_sequence<sizeof...(Args)>{});
                                                          ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp: At global scope:
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:64:50: error: ‘std::index_sequence’ has not been declared
             auto apply(F&& f, Tuple&& args, std::index_sequence<I...>)
                                                  ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:64:64: error: expected ‘,’ or ‘...’ before ‘<’ token
             auto apply(F&& f, Tuple&& args, std::index_sequence<I...>)
                                                                ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:73:38: error: expected type-specifier
                   typename Indices = std::make_index_sequence<
                                      ^
/workspace/srcdir/OpenCL-SDK/lib/include/CL/Utils/Detail.hpp:73:38: error: expected ‘>’
make[2]: *** [lib/CMakeFiles/OpenCLUtilsCpp.dir/build.make:76: lib/CMakeFiles/OpenCLUtilsCpp.dir/src/Utils/Utils.cpp.o] Error 1
make[2]: Leaving directory '/workspace/srcdir/OpenCL-SDK/build'
make[1]: *** [CMakeFiles/Makefile2:1067: lib/CMakeFiles/OpenCLUtilsCpp.dir/all] Error 2
make[1]: Leaving directory '/workspace/srcdir/OpenCL-SDK/build'
make: *** [Makefile:166: all] Error 2

Should I edit these hpp files to include some missing stdlib?

[juliohm]

It is been a while since the last time I touched C/C++, all my work nowadays is in Julia, I don't know the latest trends in standards, stdlibs, etc. Any help is appreciated. I think we are almost there 🙏🏽

[MathiasMagnus]

Yeah, the issue at hand is this:

-- The C compiler identification is GNU 4.8.5
-- The CXX compiler identification is GNU 4.8.5

I would ask what operating system this is, but GCC 4.8.5 shares the feature set of 4.8.0, which was released March 2013, so it's 9 years old snapshot of C++ and as such pre-dates C++14. I don't think we will back-port the utility libraries to C++11, as we would have to reimplement quite some metaprogramming utilities. Our baseline of testing on Linux are the compilers found in oldest supported Ubuntu LTS, which is GCC 7. We don't (currently) have the assets to have CI runners sporting older systems/toolchains. Support below that is on a best-effort basis.

I see two short-term solutions:

• Building a truly minimal OpenCL environment, meaning OpenCL-Headers and OpenCL-ICD-Loader, that is if Julia doesn't use the C++ bindings (if yes, add OpenCL-CLHPP on top). The readme of the OpenCL-ICD-Loader repo shows what to clone and how to build and depend on these two components without involving the SDK.
• The OpenCL-SDK adding an option() to omit building of the utility libraries. The rest of the SDK is slightly more conservative (CMake 3.0...3.1, C99, C++11), so people using older toolchains could still use the convenience of the SDK repo. This I can bring up today with the rest of the SDK devs.
  • Note that the SDK intends on being a full-blown developer experience, so that is why all features are opt-out, likely this option would be opt-out too.
  • With time the SDK will include the OpenCL-Layers (C++14 too) project as well.

[juliohm]

Thank you @MathiasMagnus , I am following all your suggestions. I requested GCC 7 in the cross-compilation script and followed the instructions in the OpenCL-ICD-Loader. In the first compilation step I already get errors related to C++:

/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c: In function ‘int test_long()’:
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:400:21: error: expected ‘)’ before ‘PRId64’
     printf("b:   %" PRId64 "\n", b );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:401:21: error: expected ‘)’ before ‘PRId64’
     printf("b2:  %" PRId64 " %" PRId64 " \n", b2.s[0], b2.s[1] );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:402:21: error: expected ‘)’ before ‘PRId64’
     printf("b4:  %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 "\n", b4.s[0], b4.s[1], b4.s[2], b4.s[3] );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:403:21: error: expected ‘)’ before ‘PRId64’
     printf("b8:  %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 "\n", b8.s[0], b8.s[1], b8.s[2], b8.s[3], b8.s[4], b8.s[5], b8.s[6], b8.s[7] );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:404:21: error: expected ‘)’ before ‘PRId64’
     printf("b16: %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 "\n", b16.s[0], b16.s[1], b16.s[2], b16.s[3], b16.s[4], b16.s[5], b16.s[6], b16.s[7],
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:411:29: error: expected ‘)’ before ‘PRId64’
     printf("__cl_long2:  %" PRId64 " %" PRId64 " \n", ((cl_long*)&v2)[0], ((cl_long*)&v2)[1] );
                             ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c: In function ‘int test_ulong()’:
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:460:21: error: expected ‘)’ before ‘PRIu64’
     printf("b:   %" PRIu64 "\n", b );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:461:21: error: expected ‘)’ before ‘PRIu64’
     printf("b2:  %" PRIu64 " %" PRIu64 " \n", b2.s[0], b2.s[1] );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:462:21: error: expected ‘)’ before ‘PRIu64’
     printf("b4:  %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 "\n", b4.s[0], b4.s[1], b4.s[2], b4.s[3] );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:463:21: error: expected ‘)’ before ‘PRIu64’
     printf("b8:  %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 "\n", b8.s[0], b8.s[1], b8.s[2], b8.s[3], b8.s[4], b8.s[5], b8.s[6], b8.s[7] );
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:464:21: error: expected ‘)’ before ‘PRIu64’
     printf("b16: %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 "\n", b16.s[0], b16.s[1], b16.s[2], b16.s[3], b16.s[4], b16.s[5], b16.s[6], b16.s[7],
                     ^~~~~~
/workspace/srcdir/OpenCL-Headers/build/tests/lang_cpp/../../../tests/test_headers.c:471:30: error: expected ‘)’ before ‘PRIu64’
     printf("__cl_ulong2:  %" PRIu64 " %" PRIu64 " \n", ((cl_ulong*)&v2)[0], ((cl_ulong*)&v2)[1] );
                              ^~~~~~
make[2]: *** [tests/lang_cpp/CMakeFiles/headers_cpp_220.dir/build.make:76: tests/lang_cpp/CMakeFiles/headers_cpp_220.dir/test_headers.cpp.o] Error 1
make[2]: Leaving directory '/workspace/srcdir/OpenCL-Headers/build'
make[1]: *** [CMakeFiles/Makefile2:4453: tests/lang_cpp/CMakeFiles/headers_cpp_220.dir/all] Error 2
make[1]: Leaving directory '/workspace/srcdir/OpenCL-Headers/build'
make: *** [Makefile:146: all] Error 2

Are we required to clone OpenCL-CLHPP as well? Can you please share a set of updated instructions that I can reproduce in a fresh session with GCC 7? Appreciate your help.

[bashbaug]

I'm the one responsible for these changes: KhronosGroup/OpenCL-Headers#140

I thought I might have messed something up but it looks like I'm including the right header (<inttypes.h>), which is required since C99.

I can try to dig up a gcc7 system to repro if needed. In the meantime, can you please check that the intended version if inttypes.h is being included and that it really does not have these format macro constants defined? Thanks!

[juliohm]

I'm happy with any build that works. If you have another preferred compiler, please document it and make sure that the CI build is up to date 🙏🏼 Also, it is very good practice to set CMAKE_C_STANDARD and CMAKE_CXX_STANDARD to avoid these build issues that are hard to fix by non-maintainers. Em ter., 27 de set. de 2022 12:02, Ben Ashbaugh ***@***.***> escreveu:

…

I'm the one responsible for these changes: KhronosGroup/OpenCL-Headers#140 <KhronosGroup/OpenCL-Headers#140> I thought I might have messed something up but it looks like I'm including the right header (<inttypes.h>), which is required since C99. I can try to dig up a gcc7 system to repro if needed. In the meantime, can you please check that the intended version if inttypes.h is being included and that it really does not have these format macro constants defined? Thanks! — Reply to this email directly, view it on GitHub <#58 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAZQW3PS3SNTZ447MHPSFT3WAMD6ZANCNFSM6AAAAAAQV65VSM> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[bashbaug]

Also, it is very good practice to set CMAKE_C_STANDARD and CMAKE_CXX_STANDARD to avoid these build issues that are hard to fix by non-maintainers.

Yes, agreed. We've done this in some places (e.g. OpenCL-ICD-Loader) but not in the headers.

See KhronosGroup/OpenCL-Headers#208, I'm not sure if it might help to solve this problem? On my system it adds -std=gnu99 to my gcc compiles. I'm able to compile fine without this too (gcc 9.4.0), but maybe it will help for older gcc versions?

[juliohm]

I've incorporated the diff but the error is still there with GCC 7. I will try with GCC 9 now.

[bashbaug]

Come to think of it, we have gcc 7 in our CI for OpenCL-Headers.

Example: https://github.com/KhronosGroup/OpenCL-Headers/actions/runs/3116481007/jobs/5054348256

I can't explain why this isn't working.... 😕

[juliohm]

If you want to reproduce the exact environment where I am trying to cross-compile OpenCL, it should take a few simple steps:

1. Download Julia v1.7.3 from the binaries page: https://julialang.org/downloads/oldreleases/
2. Install the BinaryBuilder package in the Julia prompt: using Pkg; Pkg.add("BinaryBuilder")
3. Launch the wizard with using BinaryBuilder; BinaryBuilder.run_wizard()
4. Provide the link to the OpenCL-Headers GitHub repository and follow the instructions

When you are done selecting the GCC compiler and commit from the repository that you want to build, it will show a prompt where you can type the CMAKE commands in the README. You should get the same error message I am getting.