RFR: 8256618: Zero: Linux x86_32 build still fails [v4]

[Aleksey Shipilev]

On Sun, 22 Nov 2020 22:53:34 GMT, David Holmes <dholmes at openjdk.org> wrote:

> I guess I'm somewhat surprised that Zero doesn't need anything that is in os_linux_x86.cpp when building for x86. It sets a bad precedent to move CPU specific code to shared code just because zero doesn't conform to the expected use of cpu specific code.

The way current sources are structured, Zero is the "cpu" unto itself. See that we have `os_cpu/linux_x86` and `os_cpu/linux_zero`, `os/linux` and `os/zero`, etc. I agree it is awkward and have consequences like this patch; it has even more consequences for error handling that wants to do arch-specific decoding... 

That said, the current patch just moves the IA32 definition to `os_linux.cpp`, where the IA32 use already is, and this IMO makes it a tad more consistent than it was before.

> Does Zero actually need this code, or could we make the call conditional?

I think this code applies to all x86 variants. As the alternative, we can skip it for Zero, hoping that Zero x86 would never face a bug like this code tries to work around.

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PR: https://git.openjdk.java.net/jdk/pull/1310