RFR: 8261125: Move VM_Operation to vmOperation.hpp

[Coleen Phillimore]

On 2/4/21 12:18 PM, Thomas Stuefe wrote:
> On Thu, 4 Feb 2021 05:38:49 GMT, Ioi Lam <iklam at openjdk.org> wrote:
>
>> vmOperations.hpp declares the VM_Operation class, as well as a hodge podge of subclasses such as VM_ForceSafepoint, VM_DeoptimizeFrame.
>>
>> Out of the 1000 hotspot .o files, about 680 include vmOperations.hpp (mostly transitively). In most cases, they just need to use the VM_Operation class.
>>
>> So we should move VM_Operation to its own header: vmOperation.hpp (no "s").
>>
>> After the refactoring, vmOperations.hpp is included only 64 times. The inclusion count of threadSMR.hpp is also reduced from 687 to 99. HotSpot build time is improved by about 0.4%.
>>
>> Tested with mach5: tier1, builds-tier2, builds-tier3, builds-tier4 and builds-tier5. Also locally: aarch64, arm, ppc64, s390, x86, and zero.
> Hi Ioi,
>
> I like all these include cleanups! How do you find these, do you analyze the include tree?
>
> I think vmOperation vs vmOperations could be confusing. But have no immediate better idea. If others are fine with it, I am too.

I thought briefly that I will be annoyed if I keep typing the extra 's' 
when editing the file, but I don't edit that file very much, so I'm fine 
with it.
Coleen
>
> Can you please enable GA so we see that our weirder platforms build?
>
> Otherwise, looks good.
>
> ..Thomas
>
> -------------
>
> Marked as reviewed by stuefe (Reviewer).
>
> PR: https://git.openjdk.java.net/jdk/pull/2398