RFR: 8366984: Remove delay slot support [v3]

[Daniel Jeliński]

On Wed, 10 Sep 2025 01:03:57 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Daniel Jeliński has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 14 commits:
>> 
>>  - Merge remote-tracking branch 'origin/master' into delay-slot
>>  - Revert scope_desc change, breaks macos-aarch64
>>  - Remove remaining comments
>>  - Update copyright
>>  - Remove commented out code
>>  - Remove unused variables
>>  - Comment out unused _unconditional_delay_slot
>>  - Remove bundle flags
>>  - Remove delay slot support from ADL
>>  - Clean up delay slot remnants from arm32 code
>>  - ... and 4 more: https://git.openjdk.org/jdk/compare/cc6d34b2...fb68b5a8
>
> src/hotspot/share/runtime/sharedRuntime.cpp line 3505:
> 
>> 3503:         nm = cb->as_nmethod();
>> 3504:         method = nm->method();
>> 3505:         for (ScopeDesc *sd = nm->scope_desc_near(fr.pc()); sd != nullptr; sd = sd->sender()) {
> 
> It's tempting to try to change this to scope_desc_at(), but also slightly risky if SPARC isn't the only reason it was needed.  Should we investigate this in a separate RFE?

[I tried](https://github.com/djelinski/jdk/actions/runs/17495967429) before I posted this PR. Apparently scope_desc_near is also needed on macosx-aarch64:

#  Internal Error (nmethod.cpp:668), pid=11090, tid=43267
#  guarantee(pd != nullptr) failed: scope must be present

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PR Review Comment: https://git.openjdk.org/jdk/pull/27119#discussion_r2335651132