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![Program Slicing
Model Slicing
GSF for Programs
A General Slicing Framework
GSF for Models
Case Study
Conclusion
GSF: Program Example1
Original Criterion Slice
x = 42
d = 23 d d = 23
Semantics is σ = {[{x → 41; d → 23}]} The slice criterion requires
that any trace in σ when projected onto the second step has a
value for d, so ω = {{d → v } | v ∈ V } Therefore the smallest set
of traces for which there exists a structural projection is
σ = {[{d → v } | v ∈ V }]}.
Tony Clark A General Model Based Slicing Framework](https://image.slidesharecdn.com/presentationfinal-111001031655-phpapp02/75/Model-Slicing-16-2048.jpg)
![Program Slicing
Model Slicing
GSF for Programs
A General Slicing Framework
GSF for Models
Case Study
Conclusion
GSF: Program Example2
Original Criterion Slice
sum=0
prod=1 prod = 1
read(i) read(i)
while(i11) { while (i11) {
sum=sum+i
prod=prod*i prod=prod*i
i=i+1 i=i+1
} prod }
Semantics is σ = {[{sum → 0}, {sum → 0; prod → 1}, {sum → 0; prod →
1; i → v }] + trace(v ) | v ∈ 0 . . . 10} ] where trace(0) = []
trace(v ) = trace(v − 1) + [{sum → i; prod →!v ; i → v }]
i∈0...v
Criterion requires that ω = {prod → v | v ∈ V } and x maps each trace onto
the last maplet for prod.
Tony Clark A General Model Based Slicing Framework](https://image.slidesharecdn.com/presentationfinal-111001031655-phpapp02/75/Model-Slicing-17-2048.jpg)
![Program Slicing
Model Slicing
A General Slicing Framework
Case Study
Conclusion
A Borrowing Step
( s1 , ok = 0 - borrow ( fred , b ) ,f , s6 )
where
s1 = ({(0 ,* , Library )[ limit = l ] ,(1 ,* , Book )[ name =n , id =1] ,
(2 , initialized , Reader )[ name = fred , id =2]} ,{})
f = [( s1 , false = 0 - hasFine ( fred ) ,... , s1 ) ,
( s1 ,2 = 0 - getReader ( fred ) ,... , s1 ) ,
( s1 ,1 = 0 - getBook ( n ) ,... , s1 ) ,
( s1 , d = 0 - getDate () ,... , s1 ) ,
( s1 ,3 = 0 - new ( Borrows ) ,[] , s2 ) ,
( s2 , ok = 3 - setReader (2) ,... , s4 ) ,
....]
s2 = ({(0 ,* , Library )[ limit = l ] ,(1 ,* , Book )[ name =n , id =1] ,
(2 , initialized , Reader )[ name = fred , id =2] ,
(3 ,* , Borrows )[]} ,{})
Tony Clark A General Model Based Slicing Framework](https://image.slidesharecdn.com/presentationfinal-111001031655-phpapp02/75/Model-Slicing-26-2048.jpg)
![Program Slicing
Model Slicing
A General Slicing Framework
Case Study
Conclusion
Refining the Slice
{[( s1 , v = l - borrow (r , b ) ,[] , s2 )] |
s1 - Snapshot ,
s2 - Snapshot ,
v - Value ,
l - Id ,
r - Str ,
b - Str }
The mapping part x2 is a refinement of x1 that maps all nested
filmstrips to [].
Tony Clark A General Model Based Slicing Framework](https://image.slidesharecdn.com/presentationfinal-111001031655-phpapp02/75/Model-Slicing-29-2048.jpg)
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