RFR: 8294962: java.base jdk.internal.module package uses ASM to modify and write module-info.class

[Adam Sotona]

On Wed, 1 Mar 2023 01:19:24 GMT, Mandy Chung <mchung at openjdk.org> wrote:

>> 8294962: java.base jdk.internal.module package uses ASM to modify and write module-info.class.
>> This patch converts it to use Classfile API.
>> 
>> Please review.
>> Thanks,
>> Adam
>
> src/java.base/share/classes/jdk/internal/module/ModuleInfoWriter.java line 37:
> 
>> 35: import jdk.internal.classfile.Classfile;
>> 36: import jdk.internal.classfile.jdktypes.ModuleDesc;
>> 37: import jdk.internal.classfile.jdktypes.PackageDesc;
> 
> I'm a bit surprised of `jdk.internal.classfile.jdktypes` package.   ClassFile API is JDK-specific.  Would `jdk.internal.classfile.constant` be more appropriate?

`jdk.internal.classfile.jdktypes` package has been renamed to `jdk.internal.classfile.java.lang.constant`
thanks for pointing it out

> src/java.base/share/classes/jdk/internal/module/ModuleInfoWriter.java line 146:
> 
>> 144: 
>> 145:                 // packages
>> 146:                 md.packages().stream().map(PackageDesc::of).toList(),
> 
> When writing `module_info.class` via ASM, it only visits the packages if there are packages that aren't exported or open.
> 
> Does the ClassFile API add `ModulePackages` attribute only if there are packages that aren't exported or open?

Yes, `Classfile::buildModule` contains logic determining if emission of `ModulePackages` is required or not.

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PR: https://git.openjdk.org/jdk/pull/11368