Latest Graal and AArch64 WTF?

[Andrew Dinn]

On 26/07/18 11:54, Doug Simon wrote:
> Does the "JVMCI-jars-only" work-around described at
> http://mail.openjdk.java.net/pipermail/graal-dev/2018-June/005413.html
> not work for you? The original mail in that thread provides some
> background as to why the build change was made.

The workaround is news to me. I saw the first note about mx
--strict-compliance being the only option available now but did not
notice the comment in the follow-up about building for AArch64.

Is this process advertised anywhere on the graal github sites? I
couldn't find anything on either of these two sites:

  https://github.com/oracle/graal
  https://github.com/graalvm/graal-jvmci-8

If not perhaps it could be added to the instructions in

  https://github.com/oracle/graal/blob/master/compiler/README.md

I'm still a little confused as to one specific though. Given that the
workaround is happy to use a pre-supplied JDK8 to perform the build
(modulo inclusion of the JVMCI jars overlay) why was there a need to
modify the hotspot sources that sit in the graal-jvmci-8 repo? Are these
hotspot changes needed to be able to run the JDK8 version of Graal on
JDK8? i.e. does this mean it is not possible to use Graal on a standard
jdk8 release?

> In terms of making Graal not require a JVMCI JDK8 to build, one would
> need to factor out all code using API specific to a JDK version. For
> each body of such code, you'd have a "placeholder" source file
> specifying its API and overlays for each JDK version. Currently, we
> collapse the JDK8 overlay into the placeholder. As a concrete example
> of what I mean, today we have:
> 
> src/org.graalvm.compiler.serviceprovider/src/org/graalvm/compiler/serviceprovider/GraalServices.java
>
> src/org.graalvm.compiler.serviceprovider.jdk9/src/org/graalvm/compiler/serviceprovider/GraalServices.java>
> Where the first file specifies the API for GraalServices as well as
> its JDK8 implementation.
> 
> We need to move to this instead:
> 
> src/org.graalvm.compiler.serviceprovider/src/org/graalvm/compiler/serviceprovider/GraalServices.java
>
> src/org.graalvm.compiler.serviceprovider.jdk8/src/org/graalvm/compiler/serviceprovider/GraalServices.java>
src/org.graalvm.compiler.serviceprovider.jdk9/src/org/graalvm/compiler/serviceprovider/GraalServices.java
>
>  Where the first file specifies only the API and all its methods
> simply throw some exception.
> 
> In addition to the Java code changes, you'd also need to modify mx to
> consider JDK8 overlays (until now, overlay support is mostly in the
> JDK9+ parts of mx).

Ok, thanks. I will try to use the recommended workaround and also look
at what is involved in fixing the problem in the Graal tree.

regards,


Andrew Dinn
-----------
Senior Principal Software Engineer
Red Hat UK Ltd
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