RFR: 8294982: Implementation of Classfile API [v36]

[Paul Sandoz]

On Thu, 2 Mar 2023 14:31:06 GMT, Adam Sotona <asotona at openjdk.org> wrote:

>> This is root pull request with Classfile API implementation, tests and benchmarks initial drop into JDK.
>> 
>> Following pull requests consolidating JDK class files parsing, generating, and transforming ([JDK-8294957](https://bugs.openjdk.org/browse/JDK-8294957)) will chain to this one.
>> 
>> Classfile API development is tracked at:
>> https://github.com/openjdk/jdk-sandbox/tree/classfile-api-branch
>> 
>> Development branch of consolidated JDK class files parsing, generating, and transforming is at:
>> https://github.com/openjdk/jdk-sandbox/tree/classfile-api-dev-branch
>> 
>> Classfile API [JEP](https://bugs.openjdk.org/browse/JDK-8280389) and [online API documentation](https://htmlpreview.github.io/?https://raw.githubusercontent.com/openjdk/jdk-sandbox/classfile-api-javadoc-branch/doc/classfile-api/javadoc/java.base/jdk/internal/classfile/package-summary.html) is also available.
>> 
>> Please take you time to review this non-trivial JDK addition.
>> 
>> Thank you,
>> Adam
>
> Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:
> 
>   StackMapFrameInfo extracted to top level from StackMapTableAttribute

src/java.base/share/classes/jdk/internal/classfile/impl/AbstractInstruction.java line 156:

> 154:         @Override
> 155:         public String toString() {
> 156:             return String.format("Store[OP=%s, slot=%d]", this.opcode(), slot());

A suggestion. I believe the `toString` output for bound and unbound instructions should be identical and it can composed solely from methods on the public instruction interface. There are some differences e.g. `Increment` and `Inc` for the unbound and bound increment instruction respectively.

If those assumptions are correct i recommend placing a static `toString` method on all unbound instructions that also have bound instructions, accepting the public instruction interface as an argument. Then the overridden `Object::toString` method defers to those. Thereby there is no duplication.
(Alas we cannot override `toString` on the instruction interface itself).

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PR: https://git.openjdk.org/jdk/pull/10982