KONNO Kazuhiro

I found a problem while trying UMA build, and opened PR #19521 as the fix. CMake build does not fail with the problem.

It turned out it requires much more work to enable UMA build than I had thought. I don't think it is worth spending time, and I opened PR #19538 instead.

Issue #19501: UMA build is not supported on AArch64 macOS

I can build JDK 21 for AArch64 Linux in my local environment, Ubuntu 22.04. - gcc 11.4.0 - libdwarf-dev 20210528-1 - libelf-dev 0.186-1build1

It seems the `OMR_GC_TLH_PREFETCH_FTA` value in the generated omrcfg.h reflects the `J9VM_GC_TLH_PREFETCH_FTA` value, as far as I tried on AArch64 Linux turning the `J9VM_` flag on and off. What happens...

`OMR_GC_TLH_PREFETCH_FTA` is defined in the generated omrcfg.h when `J9VM_GC_TLH_PREFETCH_FTA` is ON and `OMR_GC_TLH_PREFETCH_FTA` is OFF in cmake files. `J9VM_GC_TLH_PREFETCH_FTA` setting seems to override `OMR_GC_TLH_PREFETCH_FTA`. I think setting the `OMR_GC_TLH_PREFETCH_FTA` value...

@zl-wang Do you have any thoughts on: - Why linux_ppc-64_le sets `OMR_GC_TLH_PREFETCH_FTA` to OFF while `J9VM_GC_TLH_PREFETCH_FTA` is ON - Why aix_ppc-64 sets `J9VM_GC_TLH_PREFETCH_FTA` to OFF linux_ppc-64_le: https://github.com/eclipse-openj9/openj9/blob/edbf0e1a5bce0b062eba57a98c6fe3e438a49d5c/runtime/cmake/caches/linux_ppc-64_le.cmake#L42 aix_ppc-64: https://github.com/eclipse-openj9/openj9/blob/edbf0e1a5bce0b062eba57a98c6fe3e438a49d5c/runtime/cmake/caches/aix_ppc-64.cmake#L34

AArch64 platforms (Linux and macOS): `J9VM_GC_TLH_PREFETCH_FTA` is enabled, but the JIT compiler does not use the `tlhPrefetchFTA` field in `J9VMThread` at all.

@zl-wang Note that the symbol in aix_ppc-64.cmake starts with `J9VM_`, and the one in linux_ppc-64_le.cmake starts with `OMR_`. They are different symbols. Please also look at the definitions of those...

The following files in [buildspecs](https://github.com/eclipse-openj9/openj9/tree/master/buildspecs) set the `gc_tlhPrefetchFTA` flag: - linux_aarch64 - linux_arm - linux_riscv64 - linux_x86-64 - linux_x86 - osx_x86-64 - win_x86-64 - win_x86 linux_ppc-64_le.spec and linux_390-64.spec don't set...