[GR-72910] Move registerBuildTimeBootstrapIndy/Condy to the public API

[graalvmbot]

Summary

This change exposes the existing build-time bootstrap-method registration mechanism through the public Native Image Feature API.

By default, invokedynamic and constantdynamic bootstrap methods are executed at run time. Feature authors can now explicitly allow selected bootstrap methods to execute during image generation:

• DuringSetupAccess.registerBuildTimeBootstrapIndyExecutable)
• DuringSetupAccess.registerBuildTimeBootstrapCondy(Executable)

When Native Image encounters an invokedynamic or constantdynamic instruction using a registered bootstrap method, it executes that bootstrap method at build time and constant-folds the resulting call site or dynamic constant into the image. Bootstrap methods that are not registered retain the default run-time behavior.

This is useful for frameworks and language implementations that generate bytecode with custom bootstrap methods and know that those methods are safe and deterministic during image generation.

Usage

Register the bootstrap methods from a Native Image feature during duringSetup:

public final class BuildTimeBootstrapFeature implements Feature {
    @Override
    public void duringSetup(DuringSetupAccess access) {
        try {
            Method indyBootstrap = BootstrapMethods.class.getDeclaredMethod(
                            "indyBootstrap",
                            MethodHandles.Lookup.class,
                            String.class,
                            MethodType.class);

            Method condyBootstrap = BootstrapMethods.class.getDeclaredMethod(
                            "condyBootstrap",
                            MethodHandles.Lookup.class,
                            String.class,
                            Class.class);

            access.registerBuildTimeBootstrapIndy(indyBootstrap);
            access.registerBuildTimeBootstrapCondy(condyBootstrap);
        } catch (ReflectiveOperationException e) {
            throw new RuntimeException(e);
        }
    }
}

The feature can then be enabled when building the native image:

native-image --features=com.example.BuildTimeBootstrapFeature ...

Registration does not invoke the method immediately. It allows Native Image to invoke it when a corresponding dynamic call site or constant is encountered. Because any side effects occur during image generation, callers should only register bootstrap methods that are suitable for build-time execution.

[Zeavee]

@zakkak @dmlloyd,

Regarding #12453 and #12683, there is now a proper API to register bootstrap method that should be executed at build time (through Feature). Please note that FeatureImpl should not be used directly.

Sorry for the delay

[zakkak]

Thanks for the heads up @Zeavee