GH-44364: [C++] Don't export template class

[kou]

Rationale for this change

It works with MSVC but doesn't work with clang-cl.

What changes are included in this PR?

Remove ARROW_EXPORT from template classes.

Are these changes tested?

Yes but with only MSVC. We don't have clang-cl CI jobs.

Are there any user-facing changes?

Yes.

• GitHub Issue: [C++] Don't export template class #44364

[github-actions]

⚠️ GitHub issue #44364 has been automatically assigned in GitHub to PR creator.

[pitrou]

I think these were exported precisely because of MSVC at some point, so I'm surprised this isn't needed anymore.

[pitrou]

@github-actions crossbow submit win

[github-actions]

Revision: a365cbf

Submitted crossbow builds: ursacomputing/crossbow @ actions-5eb8803ff8

Task	Status
conda-win-x64-cpu-py3
conda-win-x64-cuda-py3
test-build-vcpkg-win
verify-rc-binaries-wheels-windows
verify-rc-source-windows
wheel-windows-cp310-amd64
wheel-windows-cp311-amd64
wheel-windows-cp312-amd64
wheel-windows-cp313-amd64
wheel-windows-cp39-amd64

[kou]

I'm not sure when we need ARROW_EXPORT...
For example, a365cbf is needed... Here is the error message without it:

https://github.com/apache/arrow/actions/runs/11268303462/job/31334825247#step:9:1229

D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(178): error C2220: the following warning is treated as an error
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(178): warning C4661: 'int32_t arrow::SmallBasicDecimal<int32_t>::CountLeadingBinaryZeros(void) const': no suitable definition provided for explicit template instantiation request
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(244): note: see declaration of 'arrow::SmallBasicDecimal<int32_t>::CountLeadingBinaryZeros'
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(178): warning C4661: 'int32_t arrow::SmallBasicDecimal<int64_t>::CountLeadingBinaryZeros(void) const': no suitable definition provided for explicit template instantiation request
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(244): note: see declaration of 'arrow::SmallBasicDecimal<int64_t>::CountLeadingBinaryZeros'
D:\a\arrow\arrow\build\cpp\src\arrow\CMakeFiles\arrow_io_shared.dir\Unity\unity_0_cxx.cxx(27): warning C4661: 'int32_t arrow::SmallBasicDecimal<int32_t>::CountLeadingBinaryZeros(void) const': no suitable definition provided for explicit template instantiation request
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(244): note: see declaration of 'arrow::SmallBasicDecimal<int32_t>::CountLeadingBinaryZeros'
D:\a\arrow\arrow\build\cpp\src\arrow\CMakeFiles\arrow_io_shared.dir\Unity\unity_0_cxx.cxx(27): warning C4661: 'int32_t arrow::SmallBasicDecimal<int64_t>::CountLeadingBinaryZeros(void) const': no suitable definition provided for explicit template instantiation request
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(244): note: see declaration of 'arrow::SmallBasicDecimal<int64_t>::CountLeadingBinaryZeros'
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(192): warning C4661: 'int32_t arrow::SmallBasicDecimal<int32_t>::CountLeadingBinaryZeros(void) const': no suitable definition provided for explicit template instantiation request
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(244): note: see declaration of 'arrow::SmallBasicDecimal<int32_t>::CountLeadingBinaryZeros'
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(192): warning C4661: 'int32_t arrow::SmallBasicDecimal<int64_t>::CountLeadingBinaryZeros(void) const': no suitable definition provided for explicit template instantiation request
D:\a\arrow\arrow\cpp\src\arrow/util/basic_decimal.h(244): note: see declaration of 'arrow::SmallBasicDecimal<int64_t>::CountLeadingBinaryZeros'
[184/608] Building CXX object src\arrow\CMakeFiles\arrow_array_shared.dir\Unity\unity_2_cxx.cxx.obj

[pitrou]

Do we have CI with clang-cl? Or did you test this PR yourself with it?

[kou]

Do we have CI with clang-cl?

No. But we may be able to add it because it seems that we can use it on GitHub Actions: actions/runner-images#10018

Or did you test this PR yourself with it?

@zhanweiw tested: #44310 (comment)

But this PR has more ARROW_EXPORT removes.

[pitrou]

Well, according to #44310 (comment), only the TimeScalar change is needed anyway. So this PR should be good.

[kou]

clang-cl CI: #44378

I'll merge this in a few days (for 19.0.0 not 18.0.0) if nobody objects this.

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 3 benchmarking runs that have been run so far on merge-commit d661607.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details.