On Fri, 13 Mar 2026 09:00:19 GMT, Anton Artemov <[email protected]> wrote:
>> Hi, please consider the following changes:
>>
>> This is a fix for `sp > unextended_sp` state, which can happen when
>> interpreted -> interpreted calls go through a method handle linker method.
>>
>> On x86 the issue is addressed by incrementing `r13` register value when the
>> `memberName `appendix arg is being popped out. Additionally, some changes in
>> JVMTI - related method `_remove_activation_preserving_args_entry` have to be
>> done to reflect the changes.
>>
>> On aarch64 the issue is addressed by keeping a 16-bytes aligned snapshot of
>> the expression stack pointer (eps) in `r19` instead of the regular stack
>> pointer, and an increment of that register value when the `MemberName
>> `appendix arg is being popped out. Although due to the 16-bytes alignment
>> the result of this increment is wiped out immediately, I think it is good to
>> be consistent with x86 and have instructions in place.
>>
>> Tested in tiers 1 - 7.
>
> Anton Artemov has updated the pull request with a new target base due to a
> merge or a rebase. The incremental webrev excludes the unrelated changes
> brought in by the merge/rebase. The pull request contains four additional
> commits since the last revision:
>
> - Merge remote-tracking branch 'origin/master' into
> JDK-8302745-unextended-sp-less-than-sp
> - 8302745: Don't touch ARM code.
> - 8302745: Addressed reviewer's comments.
> - 8302745: Fix for sp > unextended_sp for x86 and aarch64.
src/hotspot/cpu/aarch64/interp_masm_aarch64.cpp line 352:
> 350: void InterpreterMacroAssembler::prepare_to_jump_from_interpreted() {
> 351: // set sender sp
> 352: mov(r19_sender_sp, esp);
Suggestion:
src/hotspot/cpu/aarch64/methodHandles_aarch64.cpp line 301:
> 299: Register rmember = rmethod; // MemberName ptr; incoming method ptr
> is dead now
> 300: __ pop(rmember); // extract last argument
> 301: __ mov(r19_sender_sp, esp); // esp has been moved by 8 bytes,
> reflect it. The value in r19 will become frame's unextened_sp later on.
Suggestion:
// esp has been moved by 8 bytes, reflect it. The value in r19 will become
frame's unextened_sp later on.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/29744#discussion_r2934574300
PR Review Comment: https://git.openjdk.org/jdk/pull/29744#discussion_r2934574882
