[jdk18] RFR: 8275830: C2: Receiver downcast is missing when inlining through method handle linkers

[Vladimir Kozlov]

On Mon, 3 Jan 2022 18:45:25 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> JDK-8268405 introduced receiver downcasts when inlining through virtual calls
> when CHA reveals a unique target method under an abstract or default method.
> But it handled only cases when invocation is performed using
> `invokevirtual`/`invokeinterface` bytecodes and completely omitted `invokedynamic` and
> `MethodHandles` cases. 
> 
> The fix covers missing cases by checking whether invocation happens through 
> corresponding method handle linkers (`MethodHandle.linkToVirtual`/`MethodHandle.linkToInterface`).
> 
> Testing: hs-tier1 - hs-tier4

It is time to update Copyright year to 2022 in changed files.

test/hotspot/jtreg/compiler/cha/AbstractRootMethod.java line 64:

> 62: 
> 63:         // Implementation limitation: CHA is not performed by C1 during inlining through MH linkers.
> 64:         if (!sun.hotspot.code.Compiler.isC1Enabled()) {

I think you also need to check that C2 is enabled (could be JVMCI).

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Changes requested by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk18/pull/77