RFR: 8298099: [JVMCI] decouple libgraal from JVMCI module at runtime

[Alan Bateman]

On Mon, 5 Dec 2022 13:16:25 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

> Libgraal is compiled ahead of time and should not need any JVMCI Java code to be dynamically loaded at runtime. Prior to this PR, this is not the case due to:
> 
> * Code to copy system properties from the HotSpot heap into the libgraal heap. This is in `jdk.vm.ci.services.Services.initializeSavedProperties(byte[])` and `jdk.vm.ci.services.Services.serializeSavedProperties()`. This code should be moved to `java.base/jdk.internal.vm.VMSupport`.
> * Code to translate exceptions from the HotSpot heap into the libgraal heap and vice versa. This code should be moved from `jdk.internal.vm.ci//jdk.vm.ci.hotspot.TranslatedException` to `java.base/jdk.internal.vm.VMSupport`.
> 
> This PR makes the above changes. As a result, it's possible to build a JDK image that includes (and uses) libgraal but does not include `jdk.internal.vm.ci` or `jdk.internal.vm.compiler`. This both reduces footprint and better isolates the JAVMCI and the Graal compiler as accessing these components from Java code is now impossible.

src/hotspot/share/classfile/classLoader.cpp line 1419:

> 1417: 
> 1418: // Returns true if jdk.internal.vm.ci is present on the file system.
> 1419: bool ClassLoader::has_jvmci_module() {

Would it be more useful to pass the module name so that the function tests if the module is is in the run-time image so that ClassLoader doesn't need to know the name "jdk.internal.vm.ci"?

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PR: https://git.openjdk.org/jdk/pull/11513