[ping] RFR(L): 8221470: Print methods in exception messages in java-like Syntax.

[Lindenmaier, Goetz]

Hi David,

> I'm looking at this ...
Great, thanks!

> I'm personally of two minds here because these VM generated exceptions
> are not only delivered to Java source code. I'd like to know how other
> language developers using the JVM runtime would view this.
I thought about the other languages, too. But then I think why would the
one be better than the other, if they don't reflect the actual
code of that language?

> That aside if you're going to make a change like this then I think the
> full signature string has to be quoted in some way to delineate it
> within the larger message.
Quoting would especially help because of the space between return
type and the method name. It would be easier to capture that they
belong together.
But for consistency, we should then quote all class, field and method
names, which is currently not the case as you can easily see by looking
at the updated messages in the tests.
I thought about leaving out the return type, but that would mean to 
drop important information.
So I'm not sure here ...

Best regards,
  Goetz.

 
> > Should I split it to adapt the exceptions separately one-by-one to
> > make the change smaller and simplify the review?
> 
> I don't think that is necessary.
> 
> Thanks,
> David
> -----
> 
> > I would propose to start out with AbstractMethodError only.
> >
> > Best regards,
> >    Goetz.
> >
> >
> >
> > From: Lindenmaier, Goetz
> > Sent: Tuesday, March 26, 2019 1:06 PM
> > To: hotspot-runtime-dev at openjdk.java.net
> > Subject: RFR(L): 8221470: Print methods in exception messages in java-like
> Syntax.
> >
> > Hi,
> >
> > A row of exceptions are thrown from the hotspot runtime.
> > They print methods with their JNI signatures. To increase
> > readability and resemblance to source code, this change proposes
> > to print them in a Java-like syntax.
> >
> > Some examples:
> > current method printouts:
> >
> > test.TeMe3_B.ma()V
> > test.TeMe3_B.ma(IZ[[BF)[[D
> > test.TeMe3_B.ma([[[Ljava/lang/Object;)[[Ltest/TeMe3_B;
> >
> > improved format:
> >
> > void test.TeMe3_B.ma()
> > double[][] test.TeMe3_B.ma(int, boolean, byte[][], float)
> > test.TeMe3_B[][] test.TeMe3_B.ma(java.lang.Object[][][])
> >
> > So far, Method::name_and_sig_as_C_string() is used to print
> > these messages.
> >
> > This change implements function Method::external_name() that prints the
> better
> > format.
> > external_name() is chosen according to Klass::external_name().
> >
> > Printing the better format requires parsing the signature
> > Symbol. This is implemented in
> > void Symbol::print_as_signature_external_return_type(outputStream *os);
> > void Symbol::print_as_signature_external_parameters(outputStream *os);
> > These method names are chosen according to
> Symbol::as_class_external_name().
> >
> > See this partial webrev for the new functions:
> > http://cr.openjdk.java.net/~goetz/wr19/8221470-exMsg-signature/01-
> new_methods/
> >
> > Also, I changed a lot of exception messages to use the new format.
> > This required to adapt a row of tests. I added a test to check
> > the signature printing does not regress.  For all these changes, see
> > the full webrev:
> > http://cr.openjdk.java.net/~goetz/wr19/8221470-exMsg-signature/01/
> >
> > I hope I detected all places where method signatures are printed to
> > exception messages.
> >
> > Best regards,
> >    Goetz.
> >
> >
> >
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