RFR: 8177845: Need a mechanism to load Graal

[Doug Simon]

(adding hotspot-compiler-dev)

> On 19 Apr 2017, at 02:02, Mandy Chung <mandy.chung at oracle.com> wrote:
> 
> 
>> On Apr 18, 2017, at 3:13 PM, Doug Simon <doug.simon at oracle.com> wrote:
>> 
>> Please review these changes that make jdk.internal.vm.compiler an upgradable compiler.
>> :
>> http://cr.openjdk.java.net/~dnsimon/8177845/
> 
> Thanks for making this change.  This would simplify the way to replace JDK’s graal with the lab graal.  A couple of comments:
> 
> jdk/internal/misc/VM.java
> 
> 161      * Note that the saved system properties do not include
> 162      * the ones set by sun.misc.Version.init().
> 
> sun.misc.Version is no longer present in JDK 9.  Renamed to java.lang.VersionProps

Sorry, the webrev was out of date. I've updated it and also fixed the comment for VM::getSavedProperty.

> jdk/vm/ci/services/Services.java
> 67             Class.forName("jdk.vm.ci.runtime.JVMCI”);
> 
> JVMCI class is local in jdk.internal.vm.ci module.  An alternative may be
> to provide a static initialize method rather than Class::forName.

JVMCI is broken into fine grained "projects" and the jdk.vm.ci.runtime[1] project depends on the jdk.vm.ci.services project[2] so I cannot make a direct reference without introducing a circular dependency. I don't expect the reflection cost to be significant in practice.

> jdk/vm/ci/hotspot/HotSpotJVMCIRuntime.java
> 211         for (HotSpotJVMCIBackendFactory factory : ServiceLoader.load(HotSpotJVMCIBackendFactory.class)) {
> 
> This uses the thread context class loader to load providers.  Services::load uses 
> the system class loader to load providers.  I suspect you want this to use the 
> system class loader here too.
> 
> jdk/vm/ci/services/JVMCIServiceLocator.java
> 78         for (JVMCIServiceLocator access : ServiceLoader.load(JVMCIServiceLocator.class)) {
> 
> Same comment as above. I think you want to use system class loader to load providers.

Yes, I think you're right. I've updated the webrev with that change.

Thanks for the review.

-Doug

[1] http://hg.openjdk.java.net/jdk9/dev/hotspot/file/560d7aa083a2/.mx.jvmci/suite.py#l94
[2] http://hg.openjdk.java.net/jdk9/dev/hotspot/file/560d7aa083a2/.mx.jvmci/suite.py#l45