[OpenJDK 2D-Dev] RFR(xxxs): 8200052: libjavajpeg: Fix compile warning in jchuff.c

[Adam Farley8]

I also advocate the source code fix, as Make isn't meant to use the sort 
of logic required 
to properly analyse the toolchain version string. 

e.g. An "eq" match on 4.8.5 doesn't protect the user who is using 4.8.6, 
and Make doesn't
seem to do substring stuff unless you mess around with shells.

Plus, as people have said, it's better to solve problem x (or work around 
a specific 
instance of x) than to ignore the exception, even if the ignoring code is 
toolchain-
specific.

- Adam Farley

> On 2018-03-27 18:44, Phil Race wrote:
> 
>> As I said I prefer the make file change, since this is a change to an 
upstream library.
> 
> Newtons fourth law: For every reviewer, there's an equal and opposite 
reviewer. :) 
> 
> Here I am, advocating a source code fix. As Thomas says, the compiler 
complaint seems reasonable, and disabling it might cause us to miss other 
future errors.
> 
> Why can't we push the source code fix, and also submit it upstream?
> 
> /Magnus
> 
> 
> I've looked at jpeg-9c and it still looks identical to what we have in 
6b, so this code
> seems to have stood the test of time. I'm also unclear why the compiler 
would
> complain about that and not the one a few lines later 
> 
> 
>  819   while (bits[i] == 0)          /* find largest codelength still in 
use */
>  820     i--;
> 
> A push to jchuff.c will get blown away if/when we upgrade.
> A tool-chain specific fix in the makefile with an appropriate comment is 
more targeted.
> 
> 
> -phil.
> 
> 
> On 03/27/2018 05:44 AM, Thomas Stüfe wrote:
> 
> Hi all, 
> 
> 
> just a friendly reminder. I would like to push this tiny fix because 
tripping over this on our linux s390x builds is annoying (yes, we can 
maintain patch queues, but this is a constant error source).
> 
> 
> I will wait for 24 more hours until a reaction. If no serious objections 
are forcoming, I want to push it (tier1 tests ran thru, and me and 
Christoph langer are both Reviewers).
> 
> 
> Thanks! Thomas
> 
> 
> On Wed, Mar 21, 2018 at 6:20 PM, Thomas Stüfe <thomas.stuefe at gmail.com> 
wrote:
> 
> Hi all, 
> 
> 
> may I please have another review for this really trivial change. It 
fixes a gcc warning on s390 and ppc. Also, it is probably a good idea to 
fix this.
> 
> 
> bug: https://bugs.openjdk.java.net/browse/JDK-8200052
> webrev: 
http://cr.openjdk.java.net/~stuefe/webrevs/8200052-fix-warning-in-jchuff.c/webrev.00/webrev/
> 
> 
> This was contributed by Adam Farley at IBM.
> 
> 
> I already reviewed this. I also test-built on zlinux and it works.
> 
> 
> Thanks, Thomas
> 

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