Ramsay Jones wrote: > Josh Triplett wrote: >> Ramsay Jones wrote: >>> fix most of those problems. (the output from "make check" was about 16k >>> lines at one point!). Git also tickled a bug in sparse 0.2, which resulted >>> in some 120+ lines of bogus warnings; that was fixed in version 0.3 (commit >>> 0.2-15-gef25961). As a result, sparse version 0.3 + my patches, elicits 106 >>> lines of output from "make check". >> One note about using Sparse with Git: you almost certainly don't want to pass >> -Wall to sparse, and current Git passes CFLAGS to Sparse which will do exactly >> that. -Wall turns on all possible Sparse warnings, including nitpicky >> warnings and warnings with a high false positive rate. > > I have to say that, my initial reaction, was to disagree; I certainly want to > pass -Wall to sparse! Why not? Did you have any particular warnings in mind? > (I haven't noticed any that were nitpicky or had a high false positive rate!) If you don't mind the set of warnings you get, then sure, use -Wall. Some of the ones I had in mind: * -Wshadow. Not everyone cares. * -Wptr-subtraction-blows. This warns any time you do ptr2 - ptr1. * -Wundefined-preprocessor. This warns if you ever do #if SYMBOL when SYMBOL might not actually have a definition. Many projects do exactly that, and the C standard allows it. * -Wtypesign. Off by default for the same reason that GCC doesn't give sign mismatches by default: too many codebases with too many sloppy signedness issues that drown out other issues. > ... You should start from >> the default set of Sparse warnings, and add additional warnings as desired, or >> turn off those you absolutely can't live with. > > Why not "-Wall -Wno-nitpicky -Wno-false-positive" ;-) If you don't mind that, then sure. You might have to adjust the warning list to taste from time to time. But please do use -Wall if you feel comfortable with the warnings it produces. > ... Current Sparse from Git (post >> 0.3, after commit e18c1014449adf42520daa9d3e53f78a3d98da34) has a change to >> cgcc to filter out -Wall, so you can pass -Wall to GCC but not Sparse. > > Yes, I noticed that. Again, I'm not sure I agree. > I didn't comment on that patch, because my exposure to sparse is very limited. > So far I've only run it on git, so I can hardly claim any great experience with > the output from sparse. However, 105 lines of output (which represents 71 warnings) > for 72,974 lines of C (in 179 .c files) did not seem at all unreasonable. True; for a project the size of Git, you can reasonably handle all the warnings as you did. If you want to use -Wall with sparse, you can always pass -Wall to sparse directly, or use CHECK="sparse -Wall" cgcc. - Josh Triplett
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