RFR: 8336489: Track scoped accesses in JVMCI compiled code

[Gilles Duboscq]

On Fri, 19 Jul 2024 14:46:38 GMT, Carlo Refice <duke at openjdk.org> wrote:

> This PR adds JVMCI support to scoped access tracking introduced in #20158.
> 
> In this PR:
> * The `Method::is_scoped` flag is now exposed in JVMCI as `HotSpotResolvedJavaMethod.isScoped()`, and serialized to / deserialized from the JVMCI compiled code stream as a boolean flag.
> * To determine whether a compiled method has a scoped access, we simply check `HotSpotResolvedJavaMethod.isScoped()` returns `true` for the root method or any of the methods that were inlined in the compilation.
> * The above check is implemented as the method `HotSpotCompiledNMethod.hasScopedAccess()`, instead of as an explicit flag set in a the constructor of `HotSpotCompiledNMethod`. This keeps the change isolated to JVMCI, without requiring coordinated changes to the Graal compiler. No other changes in the compiler are necessary to benefit from the optimization.

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/HotSpotResolvedJavaMethod.java line 66:

> 64:      * @return true if Scoped annotation present, false otherwise
> 65:      */
> 66:     boolean isScoped();

Why not add this to `ResolvedJavaMethod`? If it is about compatibility you could add it as a default method that throws a `UnsupportedOperationException`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20256#discussion_r1686086922