Remove support of old code attribute format

[Harold Seigel]

Hi Remy,

I entered bug https://bugs.openjdk.java.net/browse/JDK-8232890 for this 
issue.

Our plan is to remove the hotspot code that supports the undocumented 
Code attribute format.

Thanks for pointing this out to us.

Harold

On 10/21/2019 7:32 PM, Remi Forax wrote:
> *ping*
>
> ----- Mail original -----
>> De: "Remi Forax" <forax at univ-mlv.fr>
>> À: "hotspot-dev" <hotspot-dev at openjdk.java.net>
>> Envoyé: Samedi 19 Octobre 2019 18:57:22
>> Objet: Remove support of old code attribute format
>> Hi all,
>> currently hotspot supports parsing a code attribute format [1] that is not
>> described by the JVM spec if the major version is 45 and the minor <= 2.
>>
>> Obviously, none of the bytecode tools or other VMs support that format because
>> it is not described in the JVMS (it predates Java),
>> so it can be used to create classes that can not be inspected but run on
>> hotspot.
>>
>> Someone named Chris ask us (ASM) to support that format [2], the same guy also
>> asks for the support in javap see [3].
>>
>> I think it's better to not change the VM spec but fix hotspot.
>>
>> Before logging a bug, i want to know what you guys are thinking about that.
>>
>> regards,
>> Rémi
>>
>> [1]
>> http://hg.openjdk.java.net/jdk/jdk/file/f7df2861be47/src/hotspot/share/classfile/classFileParser.cpp#l2451
>> [2] https://gitlab.ow2.org/asm/asm/issues/317888
>> [3] https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8232598