Data dependences, which relate statements that compute data values to statements that use those values, are useful for automating a variety of program-comprehension-related activities, such as reverse engineering, impact analysis, and debugging. Unfortunat

Table5:Programsusedfortheempiricalstudiesreportedinthepaper.

Subjectansitape

Benchmarkprogram

di

Compress/extractutility

replacetotunzip

Antenna-arrayspeci cationparserStatisticalinformationcombiner

2906

5511530LOC1106

100percentage of total def useassociations

806040200Figure6:Distributionofdatadependencesusingourclassi cationandOstrandandWeyuker’sclassi cation.

3In

twoofthesubjects,twocallsinvolvingfunctionpointershavebeensubstitutedwithcallshavingthesamedata- ow

e ect.

ty 1pety 3pe ty5pe ty6pe ty7pety 9pe ty10pe ty13pe ty14pety 15pety 17pe ty19pe ty20pe ty22pe st23rongwveeryak weak

ty

pe