RFR: 8177845: Need a mechanism to load Graal

[Vladimir Kozlov]

Hi Doug,

Can you consider using other name and not JDK9 for new JVMCI class? It 
will be used in JDK 10 too:

jdk.vm.ci.services.internal.JDK9;

Thanks,
Vladimir

On 4/18/17 3:13 PM, Doug Simon wrote:
> Please review these changes that make jdk.internal.vm.compiler an upgradable compiler.
> The primary requirement for this is to remove all usage of JDK internals from Graal.
> While this most involves changes in Graal, there remain a few capabilities that must
> be exposed via JVMCI. Namely:
>
> 1. Graal needs a copy of jdk.internal.misc.VM.savedProps so that it can Graal initialize
>    can use system properties that are guaranteed not to have been modified by application
>    code (Graal initialization is lazy and may occur after application code has been run).
>
> 2. Truffle needs to be able to trigger JVMCI initialization so that it can select the Graal
>    optimized implementation of the Truffle runtime.
>
> These capabilities have been added to jdk.vm.ci.services.Services. A comment has
> also been added to this class to denote the current methods to be removed
> in a subsequent bug to update the JDK copy of Graal with the upstream version which
> no longer uses the methods. The methods destined for removal are:
>
> exportJVMCITo(Class<?> requestor)
> load(Class<S> service)
> loadSingle(Class<S> service, boolean required)
>
> The first one is no longer needed as JVMCI exports itself to Graal service providers
> it loads via private API and Graal re-exports[1] JVMCI to any module the extends Graal.
> The latter 2 are no longer required as Graal uses the standard ServiceLoader. This API
> is only useful for JVMCI-8 where a hidden JVMCI class loader is used.
>
> These changes have been tested against upstream Graal. To make the Graal tests pass, 2 extra
> minor changes were required:
>
> 1. In JDK-8177663, HotSpotMemoryAccessProviderImpl::checkRead was added and throws IllegalArgumentException
>    on all error paths except one which throws AssertionError. The latter was a mistake and has been
>    fixed to also throw IllegalArgumentException.
> 2. An invalid assertion has been removed from HotSpotResolvedObjectTypeImpl::isDefinitelyResolvedWithRespectTo.
>    Up to JDK 8, it was true that all classes in java.* packages were loaded by the boot class loader.
>    This is no longer true in JDK 9 with classes like java.sql being loaded by platform class loader.
>
> As hinted above, a subsequent bug will be required to pull in the latest upstream Graal and
> remove use of JDK internal API from the jdk.aot module. The qualified exports to
> jdk.vm.internal.compiler and jdk.aot can then be removed.
>
> -Doug
>
> https://bugs.openjdk.java.net/browse/JDK-8177845
> http://cr.openjdk.java.net/~dnsimon/8177845/
>
> [1] http://openjdk.java.net/projects/jigsaw/spec/issues/#IndirectQualifiedReflectiveAccess
>
>
>