RFR: 8336489: Track scoped accesses in JVMCI compiled code [v3]

[Carlo Refice]

On Thu, 25 Jul 2024 16:03:59 GMT, Carlo Refice <duke at openjdk.org> wrote:

>> I also agree that this should be moved up to `ResolvedJavaMethod` as the annotation itself is not HotSpot specific and so could easily be relevant for any other VM using the JDK classes (e.g. SVM).
>> 
>> Note that this means you'll need to update `TestResolvedJavaMethod.java` to test the new method but that should be straightforward.
>
> I think there's something I'm missing here. I'm trying to extend `TestResolvedJavaMethod.java` to test the new method, but I can't get `isScoped()` to return true for methods with the `@Scoped` annotation such as `jdk.internal.misc.ScopedMemoryAccess#loadInternal()`.
> 
> At first I thought it was a problem with my implementation, but I also can't get `HotSpotResolvedJavaMethod#hasReservedStackAccess()` to return true for a method like the following:
> 
> @jdk.internal.vm.annotation.ReservedStackAccess
> private static void methodWithReservedStackAccess() {}
> 
> 
> The `loadInternal()` method above also has a `ForceInline` annotation, and for that one `HotSpotResolvedJavaMethod#isForceInline()` does return true.
> 
> The only difference I can see between these flags is that `isForceInline()` is stored in `Method::_flags` whereas `loadInternal()` and `hasReservedStackAccess()` are stored in `ConstMethod::_flags`. Could it be that const method flags are not being propagated properly in tests (or elsewhere)?
> 
> Here's a snippet of the test in question that I'm trying to add,
> in `compiler/jvmci/jdk.vm.ci.runtime.test/src/jdk/vm/ci/runtime/test/TestResolvedJavaMethod.java`:
> 
>     @jdk.internal.vm.annotation.ReservedStackAccess
>     private static void methodWithReservedStackAccess() {
>     }
> 
>     @Test
>     public void isScopedTest() throws NoSuchMethodException {
>         ResolvedJavaMethod rsaMethod = metaAccess.lookupJavaMethod(getClass().getDeclaredMethod("methodWithReservedStackAccess"));
> 
>         // Fails
>         assertTrue(rsaMethod.toString(), ((HotSpotResolvedJavaMethod)rsaMethod).hasReservedStackAccess());
> 
>         ResolvedJavaMethod scopedMethod = metaAccess.lookupJavaMethod(ScopedMemoryAccess.class.getDeclaredMethod("loadInternal", MemorySessionImpl.class, long.class, boolean.class, long.class));
>         // Succeeds
>         assertTrue(scopedMethod.toString(), ((HotSpotResolvedJavaMethod)scopedMethod).isForceInline());
> 
>         //Fails
>         assertTrue(scopedMethod.toString(), ((HotSpotResolvedJavaMethod)scopedMethod).isScoped());
>     }

Nevermind, looks like the issue with `hasReservedStackAccess` was the fact that the holding class has to be loaded by the boot class loader for the annotation to be picked up. Back to the drawing board...

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PR Review Comment: https://git.openjdk.org/jdk/pull/20256#discussion_r1691826841