Build fails when excluding Serial GC

[Stefan Karlsson]

On 2021-01-29 09:03, Yang Yi wrote:
> Hi,
>
> It's quite easy to reproduce this problem:
> ./configure --with-jvm-features=-serialgc ... ; make images
>
> I got the following output
> ```
> ...
> === Output from failing command(s) repeated here ===
> * For target hotspot_variant-server_libjvm_objs_genCollectedHeap.o:
> /home/qingfeng.yy/openjdk16_so_warning/jdk/src/hotspot/share/gc/shared/genCollectedHeap.cpp: In member function 'virtual void GenCollectedHeap::post_initialize()':
> /home/qingfeng.yy/openjdk16_so_warning/jdk/src/hotspot/share/gc/shared/genCollectedHeap.cpp:206:3: error: 'MarkSweep' has not been declared
>    206 |   MarkSweep::initialize();
>        |   ^~~~~~~~~
> * All command lines available in /home/qingfeng.yy/openjdk16_so_warning/jdk/build/linux-x86_64-server-release/make-support/failure-logs.
> === End of repeated output ===
> ```
> I found current JVM features contain the serial gc, but actually I can not
> build an image that does not contain serial gc. This problem has existed
> from jdk 11 to jdk head. I am somewhat surprised, so I haven't filed an
> issue on JBS. Is this really a bug? Or actually we should revise the building
> document and remove all INCLUDE_SERIALGC macros?

It's sort-of a known issue, but since we (Oracle) don't build without 
the Serial GC it has been left to be fixed later. Maybe by us, or maybe 
by someone who want's to be able to exclude the Serial GC. I won't mind 
if you want to fix this.

However, note that there are some legacy code here because 
GenCollectedHeap used to be shared code between the Serial GC and CMS. 
Now that CMS has been removed, GenCollectedHeap is actually only used by 
the Serial GC. If you look at the code you'll see that Serial code calls 
back and forth between the GenCollectedHeap (and associated classes). 
Cleaning that up is on our backlog, but is not a high-priority task. 
When/if that gets done, some of the code in the shared/ directory, will 
be moved into the serial/ directory. With that, I think most of the 
INCLUDE_SERIALGC problems will go away.

StefanK

>
> Cheers,Yang Yi
>