Initial JDK 11 RFR of JDK-8173382: Add -source 11 and -target 11 to javac - Java Bug System & JDK-8193291: Add SourceVersion.RELEASE_11

[David Holmes]

On 14/12/2017 1:51 PM, mark.reinhold at oracle.com wrote:
> 2017/12/13 15:49:53 -0800, paul.sandoz at oracle.com:
>> On 13 Dec 2017, at 14:36, mark.reinhold at oracle.com wrote:
>>> I understand that other incoming changes are waiting for the 11 version
>>> bump, but can't we at least do the straightforward parameterizations and
>>> introduce _CURRENT constants in this round?  We can leave anything that
>>> requires code generation to post-11.
>>
>> On the lang tools side that does seem easy, but I’ll defer to Joe.
>>
>> With some guidance from the build engineers i would gladly consolidate
>> class file version declaration in C/++ files with a passed in macro,
>> if this can be expediently worked out. I wanna push condy as early as
>> possible in 11 :-)
> 
> Understood, but let's do the right thing (or at least closer to that)
> with this yak while we're here.
> 
>> If we could do something in jvm.h that would be ideal. We already have
>> the definitions JVM_CLASSFILE_MAJOR_VERSION and
>> JVM_CLASSFILE_MINOR_VERSION pulled in via classfile_constants.h, so
>> how can the build process inject values into those macros?
> 
> I just went through this for the versioning changes.  The attached patch
> (against d2a837cf9ff1) does what you want, I think.

We can't do that. 
src/java.base/share/native/include/classfile_constants.h is an exported 
interface - at least at present - so it can't depend on something that 
has to come from the build. You'd have to generate the exported version 
with the appropriate value substituted.

David
-----

>> For class file versions embedded in Java code it would make it easier
>> if we had programmatic access. Perhaps we could have static methods on
>> Runtime.Version to get the major/minor class file versions?
> 
> Sure, or maybe better to make them instance methods of Runtime.  Parsing
> `System.getProperty("java.class.version")` every time is no fun.
> 
> - Mark
>