hg: valhalla/valhalla/langtools: values do not support == or !=
paul.govereau at oracle.com
Thu Jul 31 23:23:40 UTC 2014
You are right, the prototype is almost certainly wrong on this count.
My interpretation of the specification:
is that, either:
v1 == v2 ==> v1.equals(v2)
v1 == v2 ==> forall (f1,f2) in fields of (v1,v2), f1 == f2
The first one could be implemented trivially in javac, but it raises
some questions about when the programmer/compiler is required to
implement equals. The second one could also be implemented in javac, or
at the JVM level by expanding the definition, or perhaps with vcmp. We
don't have a vcmp yet, so this last option will have to wait a bit.
At the moment, == would generate an acmp, which will work fine, but is
hiding a compatibility issue. I thought making == illegal was a better
choice until we decide what should happen. Of course, it is easy to
change if we prefer an acmp for now.
On 07/31/2014 05:16 PM, Remi Forax wrote:
> On 07/31/2014 10:18 PM, paul.govereau at oracle.com wrote:
>> Changeset: 532af9586535
>> Author: pgovereau
>> Date: 2014-07-31 16:16 -0400
>> values do not support == or !=
>> ! src/share/classes/com/sun/tools/javac/comp/TransValues.java
>> ! test/tools/javac/valhalla/values/CheckClone.java
>> + test/tools/javac/valhalla/values/CheckEquals.java
>> + test/tools/javac/valhalla/values/CheckEquals.out
> Hi Paul,
> Are you sure about this one ?
> for me a == on a value type is allowed and emit a vcmp.
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