RFR: 8370939: C2: SIGSEGV in SafePointNode::verify_input when processing MH call from Compile::process_late_inline_calls_no_inline() [v4]

[Vladimir Ivanov]

On Wed, 5 Nov 2025 13:01:29 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> In test cases, `mh` is initially not constant so the method handle
>> invoke can't be inlined. It is later found to be constant, so it can
>> be turned into a direct call by
>> `Compile::process_late_inline_calls_no_inline()`. In the meantime, the
>> `CallNode` for the mh invoke is cloned (by loop switching). In the
>> process, only a shallow copy of the `JVMState` for the call is
>> made. The initial `CallNode` is the first to be processed by
>> `Compile::process_late_inline_calls_no_inline()` and that causes that
>> `CallNode` to become dead. The cloned `CallNode` is then
>> processed. The `JVMState` for that one references the initial
>> `CallNode` in its caller's `JVMState`. Because that node is dead, that
>> causes a crash. The fix I propose is to make a deep copy of the
>> `JVMState` when a `CallNode` is cloned, if a `CallGenerator` is
>> assigned to the node.
>> 
>> The other failure I see with these tests is:
>> 
>> 
>> #  Internal Error (/home/roland/jdk-jdk/src/hotspot/share/opto/compile.hpp:1091), pid=3319164, tid=3319186
>> #  assert(_number_of_mh_late_inlines > 0) failed: _number_of_mh_late_inlines < 0 !
>> 
>> 
>> because even though the `CallNode` is cloned, there's still only one
>> late inline recorded. The fix here is to increment
>> `_number_of_mh_late_inlines` when the node is cloned.
>> 
>> This was reported by the netty developers.
>
> Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review

Marked as reviewed by vlivanov (Reviewer).

src/hotspot/share/opto/compile.hpp line 472:

> 470: 
> 471:   int                           _late_inlines_pos;    // Where in the queue should the next late inlining candidate go (emulate depth first inlining)
> 472:   bool                          _has_mh_late_inlines; // Any method handle late inlining still pending?

The comment is slightly misleading. As it is now, `_has_mh_late_inlines` signals that a late inline candidate has been observed during compilation.

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PR Review: https://git.openjdk.org/jdk/pull/28088#pullrequestreview-3430876037
PR Review Comment: https://git.openjdk.org/jdk/pull/28088#discussion_r2501125577