On 2019-10-22 09:36, David Holmes wrote:
Hi Magnus,
On 22/10/2019 5:17 pm, Magnus Ihse Bursie wrote:
The -Wextra option to gcc enables a bunch of useful warnings. Some of
them, but not all, can be individually enabled or disabled. All other
libraries in OpenJDK are compiled with -Wextra, but not Hotspot.
Enabling -Wextra triggers a couple of warnings that can be
individually disabled. (The idea here is not to just permanently
disable those warnings (unless that makes sense), but to look at
these warnings one at a time and see how they can be addressed.)
My trial runs with -Wextra has already found a couple of real issues
(fixed in JDK-8213414).
I have tested that this compiles without warnings on gcc 4.8, 5.5,
6.5, 7.4 and 8.3 on x64. I have also tried building zero on x64,
aarch64 and arm32 with gcc 8.3.
Bug: https://bugs.openjdk.java.net/browse/JDK-8211073
WebRev:
http://cr.openjdk.java.net/~ihse/JDK-8211073-enable-extra-on-hotspot/webrev.01
I'm somewhat surprised that this isn't triggering more warnings, but
if not then that is a good thing. :) I wouldn't be surprised if gcc
9.x causes something else pop up.
That is because I enabled it in a personal branch a long time ago, and
have spent like the last year or so trying to fix the individual
problems to prepare for this patch. ;-)
I wouldn't count on gcc 9 bringing in anything new to -Wextra. In
general, gcc is *extremely* conservative about changing -Wextra
nowadays. Virtually all new warnings that are added are added as
indivudual warnings with explicit names to be turned on or turned off.
Only after a long vetting process does any of these gets added to
-Wextra. I think the last time anything was added to -Wextra was in like
gcc 6..? So the -Wextra is in a way a bit of a legacy system in gcc for
handling warnings.
/Magnus
Fix seems fine.
Thanks,
David
/Magnus
