From daniel.smith at oracle.com  Fri Nov  8 21:04:51 2019
From: daniel.smith at oracle.com (Dan Smith)
Date: Fri, 8 Nov 2019 14:04:51 -0700
Subject: Class validation cleanups
Message-ID: <5AB35A30-E754-4C90-AB56-3AAF206CC23B@oracle.com>

I've put together some JVMS change proposals to improve its specification of the class validation process, including class loading, format checking, and verification.

These are independent of Valhalla, but lay the groundwork for additional changes to the spec. They address things like:

- How are <init> and <clinit> methods constrained?
- Can array types be field/method receiver types? (Yes, it turns out.)
- When do we enforce the 'final' modifier on classes/methods?
- Which attributes are validated, and when?
- How does class loading handle anomalous situations?

For format checking refinements:
https://bugs.openjdk.java.net/browse/JDK-8233854
http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/format-checking-jvms.html

For class loading cleanup:
https://bugs.openjdk.java.net/browse/JDK-8233861
http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/class-loading-jvms.html

For attribute validation:
https://bugs.openjdk.java.net/browse/JDK-8233863
http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/attribute-validation-jvms.html

The last is the most disruptive, since we're proposing simply ignoring some attribute contents that has traditionally been parsed and validated. I think it may be reasonable to create a JEP for that piece.

From harold.seigel at oracle.com  Wed Nov 13 19:36:05 2019
From: harold.seigel at oracle.com (Harold Seigel)
Date: Wed, 13 Nov 2019 14:36:05 -0500
Subject: Class validation cleanups
In-Reply-To: <5AB35A30-E754-4C90-AB56-3AAF206CC23B@oracle.com>
References: <5AB35A30-E754-4C90-AB56-3AAF206CC23B@oracle.com>
Message-ID: <75ec6e33-0c97-4f56-f7e8-97ea583b6493@oracle.com>

Hi Dan,

Do you expect these spec modifications to require changes in both the 
old and new verifiers?

Thanks, Harold

On 11/8/2019 4:04 PM, Dan Smith wrote:
> I've put together some JVMS change proposals to improve its specification of the class validation process, including class loading, format checking, and verification.
>
> These are independent of Valhalla, but lay the groundwork for additional changes to the spec. They address things like:
>
> - How are <init> and <clinit> methods constrained?
> - Can array types be field/method receiver types? (Yes, it turns out.)
> - When do we enforce the 'final' modifier on classes/methods?
> - Which attributes are validated, and when?
> - How does class loading handle anomalous situations?
>
> For format checking refinements:
> https://bugs.openjdk.java.net/browse/JDK-8233854
> http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/format-checking-jvms.html
>
> For class loading cleanup:
> https://bugs.openjdk.java.net/browse/JDK-8233861
> http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/class-loading-jvms.html
>
> For attribute validation:
> https://bugs.openjdk.java.net/browse/JDK-8233863
> http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/attribute-validation-jvms.html
>
> The last is the most disruptive, since we're proposing simply ignoring some attribute contents that has traditionally been parsed and validated. I think it may be reasonable to create a JEP for that piece.

From harold.seigel at oracle.com  Wed Nov 13 21:22:21 2019
From: harold.seigel at oracle.com (Harold Seigel)
Date: Wed, 13 Nov 2019 16:22:21 -0500
Subject: Class validation cleanups
In-Reply-To: <75ec6e33-0c97-4f56-f7e8-97ea583b6493@oracle.com>
References: <5AB35A30-E754-4C90-AB56-3AAF206CC23B@oracle.com>
 <75ec6e33-0c97-4f56-f7e8-97ea583b6493@oracle.com>
Message-ID: <8d278949-7021-f6ec-2b55-e01198f2ebe4@oracle.com>

It looks like both verifiers will be affected.? For example, both 
verifiers parse method exception_tables and currently throw 
ClassFormatError.

On 11/13/2019 2:36 PM, Harold Seigel wrote:
> Hi Dan,
>
> Do you expect these spec modifications to require changes in both the 
> old and new verifiers?
>
> Thanks, Harold
>
> On 11/8/2019 4:04 PM, Dan Smith wrote:
>> I've put together some JVMS change proposals to improve its 
>> specification of the class validation process, including class 
>> loading, format checking, and verification.
>>
>> These are independent of Valhalla, but lay the groundwork for 
>> additional changes to the spec. They address things like:
>>
>> - How are <init> and <clinit> methods constrained?
>> - Can array types be field/method receiver types? (Yes, it turns out.)
>> - When do we enforce the 'final' modifier on classes/methods?
>> - Which attributes are validated, and when?
>> - How does class loading handle anomalous situations?
>>
>> For format checking refinements:
>> https://bugs.openjdk.java.net/browse/JDK-8233854
>> http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/format-checking-jvms.html 
>>
>>
>> For class loading cleanup:
>> https://bugs.openjdk.java.net/browse/JDK-8233861
>> http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/class-loading-jvms.html 
>>
>>
>> For attribute validation:
>> https://bugs.openjdk.java.net/browse/JDK-8233863
>> http://cr.openjdk.java.net/~dlsmith/class-validation/class-validation-20191107/specs/attribute-validation-jvms.html 
>>
>>
>> The last is the most disruptive, since we're proposing simply 
>> ignoring some attribute contents that has traditionally been parsed 
>> and validated. I think it may be reasonable to create a JEP for that 
>> piece.