RFR(XXS): 8135179: Fix conversion warning after 8067341
volker.simonis at gmail.com
Thu Sep 10 10:56:40 UTC 2015
On Thu, Sep 10, 2015 at 11:17 AM, Thomas Schatzl
<thomas.schatzl at oracle.com> wrote:
> On Tue, 2015-09-08 at 18:56 +0200, Volker Simonis wrote:
>> can somebody please review and sponsor the following trivial fix:
>> Change "8067341: Modify PLAB sizing algorithm to waste less"
>> introduced the following code:
>> size_t const cur_plab_sz = (double)total_waste_allowed /
>> which triggers a conversion warning with older versions of GCC and
>> potentially other compilers as well:
>> hotspot-rt/src/share/vm/gc/g1/g1EvacStats.cpp: In member function
>> 'virtual void G1EvacStats::adjust_desired_plab_sz()':
>> hotspot-rt/src/share/vm/gc/g1/g1EvacStats.cpp:96: warning: converting
>> to 'size_t' from 'double'
>> make: *** [g1EvacStats.o] Error 1
>> The warning can be easily fixed as follows:
>> size_t const cur_plab_sz = (sizte_t)((double)total_waste_allowed /
> looks good. Thanks for the fix. I can push the change.
thanks a lot for your help.
>> Thank you and best regards,
>> PS: as a side note I want to mention that we are currently disabling
>> '-Wconversion' for GCC 4.3 and later because it produces too many
>> warnings which are by default treated as errors. All the warnings
>> produced by '-Wconversion' are about narrowing conversions which may
>> result in a potential data loss.
>> It may be a good idea to fix all these implicit narrowing conversions
>> and re-enable -Wconversion warning by default.
>> But unfortunately there's quite some code which has to be changed in
>> order to meet the requirements of '-Wconversion'. A quick research
>> showed that there are currently 137 different implicit narrowing
>> conversions spread over 1785 different code locations.
>> For more details see "8135181: Re-enable '-Wconversion' for GCC 4.3
>> and later" (https://bugs.openjdk.java.net/browse/JDK-8135181) which
>> I've opened to track the issue.
>> What's the general opinion? Would it be worth wile to fix all these
>> conversion warnings by inserting implicit casts?
> I would think so that the goal is to gradually enable more warnings. I
> guess it has been turned off because nobody stepped up fixing these
> issues. :)
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