Remove support of old code attribute format

[Remi Forax]

*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