[11] RFR(S) 8207069: [AOT] we should check that VM uses the same GC as one used for AOT library generation.

[Christian Thalinger]

> On Jul 12, 2018, at 5:28 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> 
> Including GC group since I added new method to GCConfig.
> 
> http://cr.openjdk.java.net/~kvn/8207069/webrev.00/
> https://bugs.openjdk.java.net/browse/JDK-8207069
> 
> Recent Graal's changes [1] added list of GC [2] which matches Hotspot GC list [3].
> I used that to fix this issue by storing enum value from Graal in AOT config header and compare it with selected GC when AOT library is loaded into Hotspot.

The fix is correct but too strict.  For example, Serial and Parallel GC can use the same AOT library.  CMS too.

> 
> I verified the fix with all GCs combination when compiling AOT lib and using it. I also ran our hs-tier1-3 testing which includes AOT and Graal tests.
> 
> These changes are for JDK 11 so I don't need to go through Graal PR now but I would need to do that for JDK 12 to make changes in AOT code.
> 
> Thanks,
> Vladimir
> 
> [1] https://bugs.openjdk.java.net/browse/JDK-8205824
>  "[GR-10514] Use whitelist for GCs supported by Graal"
> [2] http://hg.openjdk.java.net/jdk/jdk11/file/bf686c47c109/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/HotSpotGraalRuntime.java#l137
> [3] http://hg.openjdk.java.net/jdk/jdk11/file/bf686c47c109/src/hotspot/share/gc/shared/collectedHeap.hpp#l173