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Filtering Clones forIndividual User Based on

Machine Learning Analysis

Jiachen Yang, Keisuke Hotta, Yoshiki Higo,Hiroshi Igaki, Shinji Kusumoto

Graduate School of Information Science and Technology, Osaka University

June 4, 2012

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 1 / 14

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Motivating Example

ClonesetsRed: Un-interesting

Blue: Interesting

Participants of survey

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Motivating Example

ClonesetsRed: Un-interesting

Blue: Interesting

Participants of survey1 2 3 4 5 6 7 8

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Motivating Example

ClonesetsRed: Un-interesting

Blue: Interesting

Participants of survey

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 2 / 14

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Interesting U:0 vs I:8

1542 static .char *..1543 .history_substring (string , start , end)..1544 . const char *string;..1545 . int start , end;..1546 .{..1547 . register int len ;..1548 . register char *result ;..1549 . len = end − start;..1550 . result = (char *)xmalloc (len + 1);..1551 . strncpy ( result , string + start, len);..1552 . result [ len] = '\0';..1553 . return result ;..1554 .}..

(a) lib/readline/histexpand.c

126 .char *..127 .substring (string , start , end)..128 . const char *string;..129 . int start , end;..130 .{..131 . register int len ;..132 . register char *result ;..133 . len = end − start;..134 . result = (char *)xmalloc (len + 1);..135 . strncpy ( result , string + start, len);..136 . result [ len] = '\0';..137 . return ( result );..138 .}..

(b) stringlib.c

Figure: Example of source code in bash-4.2

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 3 / 14

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Un-Interesting U:8 vs I:0

191 ... __P((char *, arrayind_t, .char *));..192 .static intmax_t subexpr __P((char *));..193 .static intmax_t expcomma __P((void));..194 .static intmax_t expassign __P((void));..195 .static intmax_t expcond __P((void));..196 .static intmax_t explor __P((void));..197 .static intmax_t expland __P((void..));

(a) expr.c

309 static int run_one_command __P((.char *));..310 .static int run_wordexp __P((char *));..311 .static int uidget __P((void));..312 .static void init_interactive __P((void));..313 .static void init_noninteractive __P((void));..314 .static void init_interactive_script __P((void));..315 .static void set_shell_name __P((char..*));

(b) shell.c

Figure: Example of source code in bash-4.2

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 4 / 14

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Disagreed U:4 vs I:4

2710 static int2711 displen (s)2712 const char *s;2713 {2714 wchar_t *wcstr;2715 size_t wclen, slen ;2716 wcstr = 0.;..2717 .slen = mbstowcs (wcstr, s, 0);..2718 .if (slen == −1)..2719 . slen = 0;..2720 .wcstr = (wchar_t *)xmalloc (sizeof .....2721 .mbstowcs (wcstr, s, slen + 1);..2722 wclen = wcswidth (wcstr, slen);2723 free (wcstr);2724 return (( int)wclen);2725 }

(a) execute_cmd.c

1098 else1099 {1100 if (wcharlist == 0)1101 {1102 size_t len.;..1103 . len = mbstowcs (wcharlist, charlist , 0);..1104 . if (len == −1)..1105 . len = 0;..1106 . wcharlist = (wchar_t *)xmalloc (sizeof .....1107 . mbstowcs (wcharlist, charlist , len + 1);..1108 }1109 if (wcschr (wcharlist , wc))1110 break;1111 }

(b) subst.c

Figure: Example of source code in bash-4.2

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 5 / 14

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Fica — the name

Filter forIndividual user on codeCloneAnalysis

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 6 / 14

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Fica — the website

Figure: Snapshot of Fica

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 7 / 14

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Compare Code Clone Similarity

Pi = possibility to be interestingPu = possibility to be un-interestingLen Pi Pi/Pu Pu Comp50 5.56% 1.18 4.72% O87 2.89% 1.11 2.59% O79 1.97% 0.69 2.87% X63 3.55% 0.64 5.57% O77 2.66% 0.46 5.83% X

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 11 / 14

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Good Experiment ResultAll training 44All evaluation 34

Matched 32Accuracy 94.12%

un-interesting 1interesting 1

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Bad Experiment ResultAll training 47All evaluation 31

Matched 14Accuracy 45.16%

un-interesting 16interesting 1

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Open Question

How to improve accuracy?By combining metrics like McCabe CyclomaticComplexity?

Thank you!

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 14 / 14

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Unmatched: User un-interesting

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 15 / 14

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Unmatched: User interesting

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 16 / 14

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Overall Workflow...1 Submits source code...2 Detects clones...3 Mark clones as “interesting”

or not...4 Records marked clones into

database...5 Studies characteristics of

marks using machine learningalgorithms

...6 Ranks unmarked clones basedon machine learning

Figure: Overall Workflowof Fica with CDT

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 17 / 14

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Calc Similarity of Clones

tf(t, d) =|t : t ∈ d|

|d| (1)

idf(t,D) = log |D|1 + |d ∈ D : t ∈ d| (2)

tfidf(t, d,D) = tf(t, d)× idf(t,D) (3)−−−−−−→tfidf(d,D) = [tfidf(t, d,D) ∀t ∈ d] (4)

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 18 / 14

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Predicting Category

sim(a, b,D) =−−−−−−→tfidf(a,D) ·

−−−−−−→tfidf(b,D) (5)

nsim(a, b,D) =

{0 , sim(a, b,D) = 0

sim(a,b,D)|sim(a,b,D)| , otherwise (6)

poss(t,M) =

{1 , |M| = 0∑

∀m∈M nsim(t,m,M)

|M| , otherwise (7)

Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 19 / 14

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Result — bashA B C D E F G H

10 20 30 40 50 60 70 80 90 100Percentage of Training Set (%)

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25

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75

100A

ccu

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(%

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Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 20 / 14

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Result — gitA B C D E F G H

10 20 30 40 50 60 70 80 90 100Percentage of Training Set (%)

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Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 21 / 14

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Result — xzA B C D E F G H

10 20 30 40 50 60 70 80 90 100Percentage of Training Set (%)

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Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 22 / 14

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Result — e2fsprogsA B C D E F G H

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Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 23 / 14

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Result — All ProjectsA B C D E F G H

10 20 30 40 50 60 70 80 90 100Percentage of Training Set (%)

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Jiachen Yang (IST, Osaka-U) Fica@IWSC2012 June 4, 2012 24 / 14