Giters

dspinellis / cqmetrics

C Quality Metrics

Geek Repo:Geek Repo

Github PK Tool:Github PK Tool

Implausibly high values for maximum statement nesting and cyclomatic complexity

dspinellis opened this issue · comments

commented
  • Maximum nesting comes out at 57 when processing the kernel of FreeBSD 1.0.
  • Maximum cyclomatic complexity comes out 810 when processing used commands of FreeBSD 2.0.
commented

Find the kernel culprit.

$ git ls-tree --name-only -r FreeBSD-release/1.0  | grep '^sys\/.*\.c$' | while read f ; do git show FreeBSD-release/1.0:$f | qmcalc | tr -d \\n; echo " $f"; done | awk '$14 > 7 {print $112, $14}'
sys/i386/isa/sound/gus_wave.c 8
sys/i386/isa/sound/gustest/gmod.c 12
sys/i386/isa/sound/gustest/gusload.c 8
sys/i386/isa/sound/gustest/midithru.c 11
sys/i386/isa/sound/gustest/pmtest.c 10
sys/i386/isa/sound/sequencer.c 10
sys/i386/isa/sound/soundcard.c 8
sys/netiso/tp_driver.c 57
sys/netiso/tp_input.c 8
sys/scsi/cd.c 16
commented

Isolate by running

git show FreeBSD-release/1.0:sys/netiso/tp_driver.c | qmcalc | awk '{print $14}'
57
commented

After de78033

$ git show FreeBSD-release/1.0:sys/netiso/tp_driver.c | ~/src/cqmetrics/src/qmcalc | awk '{print $14}'
7
commented

Reproduce the cyclomatic complexity problem.

$ git ls-tree --name-only -r FreeBSD-release/2.0  | grep -v -e '^sys\/.*\.c$' -e '^\.ref' | grep '\.c$' | sed 's|^|FreeBSD-release/2.0:|' | xargs git show | qmcalc | awk '{print $53}'
810
commented

Problem persists after de78033.

commented

Look at the cyclomatic complexity of individual files.

$ git ls-tree --name-only -r FreeBSD-release/2.0  | grep -v -e '^sys\/.*\.c$' -e '^\.ref' | grep '\.c$' | sed 's|^|FreeBSD-release/2.0:|' | while read f ; do git show $f | qmcalc | tr -d \\n; echo " $f"; done | awk '$53 > 100 {print $112, $53}' | sort -k2n
FreeBSD-release/2.0:games/adventure/main.c 344
FreeBSD-release/2.0:gnu/usr.bin/cc/cc_int/combine.c 349
FreeBSD-release/2.0:gnu/usr.bin/perl/x2p/walk.c 358
FreeBSD-release/2.0:gnu/usr.bin/cc/cc_int/cse.c 361
FreeBSD-release/2.0:gnu/usr.bin/cc/cc1/c-lex.c 379
FreeBSD-release/2.0:gnu/usr.bin/cc/cc1plus/lex.c 396
FreeBSD-release/2.0:gnu/usr.bin/cc/cc_int/reload.c 454
FreeBSD-release/2.0:gnu/usr.bin/as/config/tc-m68k.c 504
FreeBSD-release/2.0:gnu/usr.bin/cc/cc1plus/decl.c 564
FreeBSD-release/2.0:gnu/usr.bin/cc/cc_int/jump.c 569
FreeBSD-release/2.0:gnu/usr.bin/perl/perl/toke.c 577
FreeBSD-release/2.0:gnu/usr.bin/cc/cc_int/fold-const.c 624
FreeBSD-release/2.0:gnu/usr.bin/cc/cc_int/expr.c 632
FreeBSD-release/2.0:gnu/usr.bin/cc/cc_int/insn-recog.c 680
FreeBSD-release/2.0:gnu/usr.bin/perl/perl/eval.c 810