RFR(M): : Various minor code improvements (compiler)

[Lindenmaier, Goetz]

Hi Tobias, 

> I can sponsor your fix but since we are close to JDK 9 FC, we are not allowed
> to push enhancements to hs-comp. Shouldn't this be a "bug" anyway?
Thanks for reviewing and the offer to sponsor!
I changed the Jira issue to bug.  Sorry for being that close to FC with my RFR.

> > - size of pointer passed to jio_snprintf()
> Please also fix the indentation in line 6004.
Fixed.

> > classLoader.cpp
> > - jio_snprintf does null termination. But it might return -1 if truncated,
> >   in this case array access at -1.
> You can remove "int n;"
Fixed.

> > generateOopMap.cpp
> > - Remaining fields not initialized.
> I would put the loop bodies in a new line.
Fixed.

> > relocator.cpp
> > - delta might be -4 ... assert returns. 
> I don't understand this change. If delta is -4, the assert in the baseline version
> is triggered. With your fix, the assert is triggered as well.

Sorry, that's a bad comment.  I meant that the assert does not 
protect against getting -4 in that line, because coverity knows 
about -XX:SuppressErrorAt.  But that's pointless, as assert goes
away in product builds anyways.  

The assert shall be triggered, therefore I moved it out of the if().
But the if() now protects against oob with -4 or smaller.

I also rebased the change, and added you as reviewer.  Find the new
Webrev here:
http://cr.openjdk.java.net/~goetz/wr16/8140594-covCo/webrev.01/
And the incremental patch:
http://cr.openjdk.java.net/~goetz/wr16/8140594-covCo/webrev.01/incremental_diff.patch

Best regards,
  Goetz.