Hi Magnus, On 27/09/2018 8:47 AM, Magnus Ihse Bursie wrote:
Anyone from Hotspot who can review the code changes?
I had looked at this but it is unclear whether the casts are the right fix or whether we have a poor type selection in the first place. For example,
./share/opto/node.hpp: enum { NO_HASH = 0 };
defines NO_HASH which is implicitly treated as int but then it's used
everywhere as uint - which just seems odd.
So I'm unclear whether this needs more indepth examination by the various code owners.
Thanks, David
/Magnus On 2018-09-24 22:31, Magnus Ihse Bursie wrote:The -Wextra option to gcc enables a bunch of useful warnings.[1] 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 on Hotspot triggers a couple of warnings for zero that can be individually disabled.However, -Wextra also includes some check that cannot be disabled individually, so to be able to add this, we must at the same time fix those warnings.The warnings that cannot be disabled and which have been triggered in Hotspot is "enumeral and non-enumeral type in conditional expression" and "base class should be explicitly initialized in the copy constructor". The former complains about mixing enums and integers in the tertiary operator (x ? enum_val : int_val). If you think that gcc is a bit too picky here, I agree. It's not obvious per se that the added casts improve the code. However, this is the price we need to pay to be able to enable -Wextra, and *that* is something that is likely to improve the code.The second warning about the copy constructor is, for what I can tell, a highly valid warning and the code it warned on was indeed broken. As far as I can tell, in a derived copy constructor you should always explicitly initialize the base class.Bug: https://bugs.openjdk.java.net/browse/JDK-8211073WebRev: http://cr.openjdk.java.net/~ihse/JDK-8211073-remove-Wno-extra-from-hotspot/webrev.01/Magnus [1] https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
