[master] RFR: Load Klass from header, C1 [v11]

[Roman Kennke]

On Tue, 11 Jan 2022 16:51:05 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Roman Kennke has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 39 commits:
>> 
>>  - Merge branch 'master' into klass-from-header-c1
>>  - Merge branch 'master' into klass-from-header-c1
>>  - AArch64 implementation
>>  - Merge remote-tracking branch 'origin/klass-from-header-c1' into klass-from-header-c1
>>  - Merge remote-tracking branch 'upstream/master' into klass-from-header-c1
>>  - Increase code size estimate
>>  - Merge branch 'master' into klass-from-header-c1
>>  - Merge remote-tracking branch 'jdk-upstream/master' into klass-from-header-c1
>>  - Merge remote-tracking branch 'upstream/master' into klass-from-header-c1
>>  - Basic arm implementation
>>  - ... and 29 more: https://git.openjdk.java.net/lilliput/compare/af5b0d92...bc5b45e9
>
> src/hotspot/cpu/x86/c1_Runtime1_x86.cpp line 1118:
> 
>> 1116:       {
>> 1117:         StubFrame f(sasm, "load_klass", dont_gc_arguments);
>> 1118:         sasm->save_live_registers_no_oop_map(true);
> 
> I presume calling `*_no_oop_map` here is intentional, and valid for `call_VM_leaf`? I.e. no safepoint expected here?

Yes exactly, leaf calls don't require an oop map.

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PR: https://git.openjdk.java.net/lilliput/pull/20