RFR: 8370978: Zero JVM fails to build on i386 after JDK-8351149

[Vladimir Petko]

On Fri, 21 Nov 2025 15:00:41 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> This PR partially reverts  JDK-8351149 to restore zero build on 32 bit platforms.
>> 
>> Reverted changes to:
>>  -` os::dll_load`, `os::Linux::dlopen_helper`  - the functions  required to load the shared libraries
>> 
>> Testing (in Ubuntu 26.04 i386 chroot):
>> 
>> $ sh configure --with-jvm-variants=zero --disable-precompiled-headers  --with-jtreg=/home/vladimirp/git/jtreg/build/images/jtreg --disable-warnings-as-errors
>> ...
>> $ make images
>> Building target 'images' in configuration 'linux-x86-zero-release'
>> Warning: No SCM configuration present and no .src-rev
>> Updating images/sec-bin.zip
>> Finished building target 'images' in configuration 'linux-x86-zero-release'
>> $
>
> src/hotspot/os/linux/os_linux.cpp line 1775:
> 
>> 1773: #if  (defined IA32)
>> 1774:   static  Elf32_Half running_arch_code=EM_386;
>> 1775: #elif   (defined AMD64) || (defined X32)
> 
> Do you need `X32` case here? I don't think anything wants it.

I think Debian wants it:
``Architecture: alpha amd64 arc armel armhf arm64 hppa i386 ia64 loong64 mips mipsel mips64 mips64el powerpc ppc64 ppc64el m68k riscv64 sh4 sparc sparc64 s390x x32``[1]

[1] https://salsa.debian.org/openjdk-team/openjdk/-/blob/master/debian/control?ref_type=heads#L39

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PR Review Comment: https://git.openjdk.org/jdk/pull/28406#discussion_r2554273480