RFR: 8300197: Freeze/thaw an interpreter frame using a single copy_to_chunk() call [v2]
Fei Yang
fyang at openjdk.org
Wed Apr 26 11:45:28 UTC 2023
On Fri, 21 Apr 2023 13:09:37 GMT, Fredrik Bredberg <duke at openjdk.org> wrote:
>> On certain architectures (like AARCH64) padding may be inserted between the locals and the rest of the stack frame in order to keep the frame pointer 16-byte-aligned.
>>
>> This padding is currently not freezed, instead freezing of a single interpreter stack frame is done using two separate copy_to_chunk() calls (see recurse_freeze_interpreted_frame). Likewise, thawing is done using two separate copy_from_chunk() calls.
>>
>> This poses a bit of a problem when trying to relativize stack addresses in interpreter frames ([JDK-8289296](https://bugs.openjdk.org/browse/JDK-8289296)). Since relative offsets may need to be changed during freezing and thawing.
>>
>> By both freezing and thawing the padding we remove the need to change any relative offsets in runtime.
>>
>> Tested tier1-tier8 on supported platforms, found no new issues. PowerPC and RISC-V was sanity tested using Qemu.
>
> Fredrik Bredberg has updated the pull request incrementally with one additional commit since the last revision:
>
> Updated after review
FYI: I also performed tier1-3 tests on linux-riscv64 unmatched boards, result looks good.
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PR Comment: https://git.openjdk.org/jdk/pull/13477#issuecomment-1523270676
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