On Fri, 15 Nov 2024 15:30:05 GMT, Coleen Phillimore <cole...@openjdk.org> wrote:
>> This change adds a couple of comments, removes some ancient bootstrapping
>> code, and adds an old test that we call the verifier for redefining a class,
>> even one in the bootclass path.
>>
>> The fix for always verifying redefined classes was actually pushed with
>> JDK-8341094, where the verifier code respected the parameter
>> "should_verify_class". By default this parameter follows the -Xverify
>> setting. For redefinition, this is passed as true. The rest of the fix
>> removes the special bootstrap loader cases that may have failed early on in
>> the JDK development with -Xverify:all but now no longer do. If someone
>> tries to redefine these classes, they should also do the verification on the
>> redefined bytecodes.
>>
>> Tested with tier1-4.
>
> Coleen Phillimore has updated the pull request incrementally with one
> additional commit since the last revision:
>
> Reduce test, fix bug in verifier, move and add comments to
> is_eligible_for_verification.
Thanks for answering David. The new class should get a VerifyError not a
ClassFormatError - the bytecodes were incorrect, as detected by the verifier.
It's not missing a code attribute but the code is truncated as reported with
-Xlog:exceptions:
[0.339s][info][exceptions] Exception <a
'java/lang/VerifyError'{0x00000007ff8850c8}: Control flow falls through code end
[ ] Exception Details:
[ ] Location:
[ ] java/lang/VerifyError.<init>()V @0: <invalid>
[ ] Reason:
[ ] Error exists in the bytecode
[ ] Bytecode:
[ ] 0000000:
[ ] > (0x00000007ff8850c8)
[ ] thrown
[/scratch/cphillim/hg/jdk-ci-pd/open/src/hotspot/share/classfile/verifier.cpp,
line 293]
[ ] for thread 0x000075ea2cbbe260
In the test the methods are here just don't have anything in them:
{
methodVisitor = classWriter.visitMethod(ACC_PUBLIC, "<init>",
"()V", null, null);
methodVisitor.visitCode();
methodVisitor.visitEnd();
}
{
methodVisitor = classWriter.visitMethod(ACC_PUBLIC, "<init>",
"(Ljava/lang/String;)V", null, null);
methodVisitor.visitCode();
classWriter.visitEnd();
}
So VerifyError is the right exception. It might be that you need to add some
nop() bytecode or something to generate the code attribute?
-------------
PR Comment: https://git.openjdk.org/jdk/pull/22116#issuecomment-2640709606
