RFR: 8358751: C2: Recursive inlining check for compiled lambda forms is broken
Roland Westrelin
roland at openjdk.org
Thu Aug 28 11:53:43 UTC 2025
On Fri, 22 Aug 2025 01:24:52 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:
> Recursive inlining checks are relaxed for compiled LambdaForms. Since LambdaForms are heavily reused, the check is performed on `MethodHandle` receivers instead.
>
> Unfortunately, the current implementation is broken. JVMState doesn't guarantee presence of receivers for caller frames.
> An attempt to fetch pruned receiver reports unrelated info, but, in the worst case, it ends up as an out-of-bounds access into node's input array and crashes the JVM.
>
> Proposed fix captures receiver information as part of inlining and preserves it on `JVMState` for every compiled LambdaForm frame, so it can be reliably recovered during subsequent inlining attempts.
>
> Testing: hs-tier1 - hs-tier8
>
> (Special thanks to @mroth23 who prepared a reproducer of the bug.)
Looks good to me.
-------------
Marked as reviewed by roland (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/26891#pullrequestreview-3164532968
More information about the hotspot-compiler-dev
mailing list