Build fails when excluding Serial GC

[Magnus Ihse Bursie]

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?

About a year ago I opened 
https://bugs.openjdk.java.net/browse/JDK-8240224, to fix this (and other 
things). This caused quite a heated debate [1], and the result was that 
I closed the bug again.

In summary, my understanding is that hotspot developers view the 
serialgc as essential, and that there exists no reason beyond toy 
applications to remove it from compilation. But furthermore the 
INCLUDE_SERIALGC macros should remain, even though they do not really 
work, since they function as markers of intent for the code. I don't  
agree 100% with this stance, but it's not my code to complain about. :-)

Possibly, the configure script should be changed so it does not look 
like it's possible to exclude the serialgc...

/Magnus


[1] 
https://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2020-March/028779.html

>
> Cheers,Yang Yi
>