[12] RFR(S) 8209165: [GRAAL] Skip Graal build if C1 is not present

[Liu Xin]

Vladimir, 

I am quite new area.  Why Graal needs its own GC and small runtime?  Theoretically, jaotc compiles some Java classes. It doesn’t need to know that those classes are themselves. 
My original thought is straight-forward. Compile Graal classes using JOT, load them to avoid from warming-up.

I compiled both modules: 
 ./jdk/bin/jaotc --module jdk.internal.vm.ci --output libHotspotCI.dylib 
 ./jdk/bin/jaotc --module jdk.internal.vm.compiler --output libHotspotCompiler.dylib

And I loaded them to run. 
./jdk/bin/java -XX:+PrintCompilation \
     -XX:+UnlockExperimentalVMOptions \
     -XX:+EnableJVMCI \
     -XX:+UseJVMCICompiler  -XX:AOTLibrary=./libHotspotCI.dylib:./libHotSpotCompiler.dylib  -cp .  Demo |& tee jvmci_with_aot_graal.output

Does it work? I took a look the output of PrintCompilation. 
I found many methods are marked 'made not entrant’.   It means that hotspot deoptimize them right? 


> On Aug 9, 2018, at 11:26 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> 
> 
> My main motivation is that it is not supported configuration for us. And if you don't use Graal you waste space with Graal module.