RFR: 8301703: java.base jdk.internal.foreign.abi.BindingSpecializer uses ASM to generate classes [v2]

[Chen Liang]

On Thu, 30 Mar 2023 19:50:47 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/foreign/abi/BindingSpecializer.java line 216:
>> 
>>> 214:         if (PERFORM_VERIFICATION) {
>>> 215:             boolean printResults = false; // only print in case of exception
>>> 216:             CheckClassAdapter.verify(new ClassReader(bytes), null, printResults, new PrintWriter(System.err));
>> 
>> Classfile API provides verification functionality as well, as seen here:
>> https://github.com/openjdk/jdk/blob/83cf28f99639d80e62c4031c4c9752460de5f36c/test/jdk/jdk/classfile/ClassHierarchyInfoTest.java#L105
>
> Does this provide additional verification over what is already done just by generating the class?
> 
> For instance, IIRC the ASM verifier could catch e.g. stack underflow, but that seems to be caught already by the new implementation without running the verifier.

Yes, for instance, the class generation doesn't check operand stack underflow, that you can generate code with invalid pops. The classfile verifier catches this: https://github.com/openjdk/jdk/blob/83cf28f99639d80e62c4031c4c9752460de5f36c/src/java.base/share/classes/jdk/internal/classfile/impl/verifier/VerificationFrame.java#L153

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PR Review Comment: https://git.openjdk.org/jdk/pull/13247#discussion_r1153732811