8370251: C2: Inlining checks for method handle intrinsics are too strict

[iwanowww]

C2 performs access checks during inlining attempts through method handle
intrinsic calls. But there are no such checks happening at runtime when
executing the calls. (Access checks are performed when corresponding method
handle is resolved.) So, inlining may fail due to access checks failure while
the call always succeeds at runtime.

The fix is to skip access checks when inlining through method handle intrinsics.

Testing: hs-tier1 - hs-tier4

---

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Issue

• JDK-8370251: C2: Inlining checks for method handle intrinsics are too strict (Enhancement - P4)

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[mlbridge]

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[vnkozlov]

Can you explain why only here you pass check_access and expect it is true in all other places?

[liach]

Similar question, should we add an assert for check_access before the resolve_invoke in Compile::optimize_inlining?

[iwanowww]

Can you explain why only here you pass check_access and expect it is true in all other places?

@vnkozlov That's the only case which was overlooked in JDK-8062280. All other cases aren't exercised for MH intrinsic methods and the asserts are there to verify that. If they start to fail, it'll signal that there may be a missing optimization opportunity.

should we add an assert for check_access before the resolve_invoke in Compile::optimize_inlining?

@liach good question, it makes sense to separately take a closer look at this particular case. My first impression is check_access should be passed into resolve_invoke rather than asserting check_access == true before resolve_invoke.