RFR: 8262368: wrong verifier message for bogus return type

[David Holmes]

On Fri, 26 Feb 2021 20:07:49 GMT, Harold Seigel <hseigel at openjdk.org> wrote:

> Please review this small change to fix some verifier error messages.  If a method's descriptor has a void return signature, but contains a bytecode such as 'ireturn' or 'areturn'. then it will get a VerifyError exception with the message "Method descriptor has a void return type".   Conversely, if a method's descriptor has a non-void return signature, but contains a 'return' bytecode then it will get a VerifyError exception with the message "Method descriptor has a non-void return type".
> 
> A sample error message looks like:
> Error: Unable to initialize main class Hi
> Caused by: java.lang.VerifyError: Method descriptor has a void return type
> Exception Details:
>   Location:
>     Hi.noRet(I)V @1: ireturn
>   Reason:
>     Type integer (current frame, stack[0]) is not assignable to top (from method signature)
>   Current Frame:
>     bci: @1
>     flags: { }
>     locals: { integer }
>     stack: { integer }
>   Bytecode:
>     0000000: 08ac
> 
> The fix was tested with Mach5 tiers 1 and 2 on Linux, Mac OS, and Windows, tiers 3-5 on Linux x64. and the JCK Lang and VM tests on Linux x64.
> 
> Thanks, Harold

Hi Harold,

Sorry I don't like the new messages. See below.

Thanks,
David

src/hotspot/share/classfile/verifier.cpp line 1678:

> 1676:           if (return_type != VerificationType::bogus_type()) {
> 1677:             verify_error(ErrorContext::bad_code(bci),
> 1678:                          "Method descriptor has a non-void return type");

I prefer the original text. The new text makes me have to think about what the actual problem is too much.

src/hotspot/share/classfile/verifier.cpp line 3152:

> 3150:     verify_error(ErrorContext::bad_type(bci,
> 3151:         current_frame->stack_top_ctx(), TypeOrigin::signature(return_type)),
> 3152:         "Method descriptor has a void return type");

I would prefer "Method does not expect a return value".

-------------

Changes requested by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/2757