RFR (L, tedious again, sorry) 8189610: Reconcile jvm.h and all jvm_md.h between java.base and hotspot

mandy chung mandy.chung at oracle.com
Fri Oct 27 17:47:21 UTC 2017

On 10/27/17 7:08 AM, coleen.phillimore at oracle.com wrote:
> On 10/27/17 9:37 AM, David Holmes wrote:
>> The one file that is needed is a hotspot file - jvm.h defines the 
>> interface that hotspot exports via jvm.cpp.
>> If you leave jvm.h in hotspot/prims then a very large chunk of your 
>> boilerplate changes are not needed. The JDK code doesn't care what 
>> the name of the directory is - whatever it is just gets added as a -I 
>> directive (the JDK code will include "jvm.h" not "prims/jvm.h" the 
>> way hotspot sources do.
>> This isn't something we want to change back or move again later. 
>> Whatever we do now we live with.
> I think it belongs with jni.h and I think the core libraries group 
> would agree.   It seems more natural there than buried in the hotspot 
> prims directory.  I guess this is on hold while we have this debate.   
> Sigh.
> Actually with -I directives, changing to jvm.h from prims/jvm.h would 
> still work.   Maybe we should change the name to jvm.hpp since it's 
> jvm.cpp though?   Or maybe just have two divergent copies and close 
> this as WNF. 

I also think hotspot/prims is not a good location. 
src/java.base/share/include is a well-defined location for native header 
files.  Maybe internal header files could be placed in include/internal 
but this is a separate issue .  I should create an issue for jvm.h and 
jmm.h (I looked at the files under the include directory and jvm.h and 
jmm.h are the only two internal header files in the include directory).

I do think removing the duplicated copy of jvm.h is a good change. This 
is finally possible with the consolidated repository and we no longer 
need to update two copies of jvm.h for any change to the JVM 
interface.   This change will work with -I directive setting to the new 
location, if changed later.

What do you think?


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