RFR: 8177845: Need a mechanism to load Graal

Christian Thalinger cthalinger at twitter.com
Wed Apr 19 18:24:48 UTC 2017

I lost track a bit but why are we exporting jdk.vm.ci.services to the world now?

 module jdk.internal.vm.ci {
-    exports jdk.vm.ci.services to jdk.internal.vm.compiler;
+    exports jdk.vm.ci.services;

> On Apr 18, 2017, at 9:16 PM, Doug Simon <doug.simon at oracle.com> wrote:
> (adding hotspot-compiler-dev)
> 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-8177673, 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

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