why does AOTLib::verify_config check for UseConcMarkSweepGC?

[Vladimir Kozlov]

What do you mean CMS does not affect code generation?

http://hg.openjdk.java.net/jdk9/dev/hotspot/file/232d93f11c49/src/share/vm/opto/graphKit.cpp#l3861

Vladimir

On 6/16/17 8:09 AM, Christian Thalinger wrote:
> Could someone remind me, why are we checking for UseConcMarkSweepGC?
> 
> // Check flags
>    verify_flag(_config->_useCompressedOops, UseCompressedOops, 
> "UseCompressedOops");
>    verify_flag(_config->_useCompressedClassPointers, 
> UseCompressedClassPointers, "UseCompressedClassPointers");
>    verify_flag(_config->_useG1GC, UseG1GC, "UseG1GC");
>    verify_flag(_config->_useCMSGC, UseConcMarkSweepGC, 
> "UseConcMarkSweepGC");
> 
> useCMSGC does not affect code generation:
> 
> ~/jdk9/hotspot$ ack useCMSGC
> src/jdk.aot/share/classes/jdk.tools.jaotc.binformat/src/jdk/tools/jaotc/binformat/BinaryContainer.java
> 303:                                   graalHotSpotVMConfig.useCMSGC,
> 
> src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/GraalHotSpotVMConfig.java
> 213:    public final boolean useCMSGC= getFlag("UseConcMarkSweepGC", 
> Boolean.class);
> 
> src/share/vm/aot/aotCodeHeap.cpp
> 155:  verify_flag(_config->_useCMSGC, UseConcMarkSweepGC, 
> "UseConcMarkSweepGC");
> 
> src/share/vm/aot/aotCodeHeap.hpp
> 105:  bool _useCMSGC;
> 
> Is there some object-layout thing I am forgetting?