Research funded by SSF RISE-PARACOMP,
CUGS Graduate School, LiU Ceniit
Proc. ICSE-2007 Minneapolis
Joint work with Mikhail Chalabine
IDA / PELAB
Linköpings universitet, Sweden
Christoph Kessler
in Static Aspect Weaving and Transformations
Automated Roundtrip Engineering
time
Aspect source
WovenCode
C. Kessler, IDA, Linköpings universitet.
Core source
WovenCode
2
ARE (Automatic Roundtrip Engineering) Problem:
How to trace back and consistently commit
(manual) changes in transformed code to the right
source of origin?
Sequences of (syntactic) program
transformations (weaving steps)
Interactive (manual) editing
Rule-based source-to-source transformation
C macro expansion
Static Aspect Weaving
...
Woven
Core’’
Woven
Core’
Woven
Core
weave
weave
weave
Application
Core
Static Aspect Weaving
... and other program transformations
Manual
Editing
Aspect
Advice
Aspect
Advice
NT(v1)…NT(vk)
T
C. Kessler, IDA, Linköpings universitet.
3
Syntactic substitutability of Tw
only with tree (fragment) of type compatible to NT(w)
Generic CST / tree fragment: CST with ”open” leaves
(= non-expanded nonterminals)
Syntactic Type of CST:
NT( root )
Production NT(w)
Inner node w with children v1,…,vk:
Leaf node b annotated with terminal: NT(b)
Inner nodes w annotated with nonterminal: NT(w)
Including whitespaces, semicolons, comments etc.
CST: Parse tree / Derivation tree
Formalisation:
Concrete Syntax Tree (CST)
Leaf_word (Tw )
Tw
w
v
w
D
C. Kessler, IDA, Linköpings universitet.
Notation:
C
TE
TB T TD
C
TA
A B
T
T
E
Γ
T’
F
ΓF
Γ
4
G
ΓG
m
r
A
v
w
F
C
C
G
T’
E
T’
T’
F T’ G
T’
A
T’
E
Syntactically correct
if NT(w) = NT(r)
and NT(v) = NT(m)
(1,1)-Double-Grafting-Transformation:
Formalisation (2)
Double-Grafting Transformation on CSTs
v
w
D
C. Kessler, IDA, Linköpings universitet.
C
TE
TB TC TD
TA
A B
T
E
F
ΓF
Γ
5
G
ΓG
m
r
A
v
w
F
C
G
T’
E
T’
T’
F T’
C G
T’
A
T’
With missing proceed()-pseudocall (= no m-node):
(1,0)-Double-Grafting Transformation
Application of an advice at a join point (shadow)
is a (1,1)-Double-Grafting-Transformation
Static Aspects (before, after, around join point)
(e.g. early version of Aspect-J)
Example 1: Static Aspect Weaving
E
C. Kessler, IDA, Linköpings universitet.
AOP Example
6
The woven code is in
Aspect-J not visible
for the programmer!
(Weaving is done at
bytecode level …)
v
w
TE
D
C. Kessler, IDA, Linköpings universitet.
C
TB TC TD
TA
A B
T
E
F
ΓF
Γ
7
G
ΓG
m
r
A
v
w
F
C
G
T’
E
T’
T’
F T’
C G
T’
A
T’
Editor coupled with CST search structure –
Clicking / Cursor on program point locates CST-node
Program again syntactically correct after editing
Requirements:
Delete, replace: (1,0)-Double-Grafting-Transformation
Insert: (1,1)-Double-Grafting-Transformation
Example 2: Editing
E
vk
Dk
E
vi l
F
C. Kessler, IDA, Linköpings universitet.
8
A
F
r
G1
w
ml
vi 1
G1
m1
C i1
where vi j in { v1, …, vk } for j = 1, …, l,
and NT(mj) = NT(vi j)
vi 1 , …, mk
C1 D1 C2 D2 Ck
v2
+ Mapping: m1
A B
v1
w
( k, l )-Double-Grafting-Transformation
C il
vi l
Gl
Gl
E
MAX( X, Y )
vk
C. Kessler, IDA, Linköpings universitet.
A B C1 D1 C2 D2 Ck Dk E
v1 v2
w
F
9
G1
m1 ml
r
Gl
A F C i1
G1
vi 1
C il
vi l
w
Gl
( (X) > (Y)? X : Y )
is a (2,4)-Double-Grafting-Transformation
… = MAX( u+1, 23 );
#define
Macro Expansion
Example 3: C - Preprocessor
E
vk
C. Kessler, IDA, Linköpings universitet.
A B C1 D1 C2 D2 Ck Dk E
v1 v2
w
F
10
G1
m1 ml
r
Gl
A F C i1
G1
vi 1
2 * id:1
is a (2,1)-Double-Grafting-Transformation
@expr: @id:1 + @id:1
Generic Transformation Rule
Example 4: Rule-based Source-toSource Transformation Systems
C il
vi l
w
Gl
E
time
11
Aspect source
WovenCode
C. Kessler, IDA, Linköpings universitet.
Core source
WovenCode
ARE (Automatic Roundtrip Engineering) Problem:
How to trace back and consistently commit
(manual) changes in transformed code to the right
source of origin?
Sequences of (syntactic) program
transformations (weaving steps)
Interactive (manual) editing
Rule-based source-to-source transformation
C macro expansion
Static Aspect Weaving
...
Woven
Core’’
Woven
Core’
Woven
Core
weave
weave
weave
Application
Core
Static Aspect Weaving
... and other program transformations
Manual
Editing
Aspect
Advice
Aspect
Advice
C. Kessler, IDA, Linköpings universitet.
Commit update consistently?
Commit
Ignore
Commit
Ignore
12
Thismodification
modificationapplies
appliestotoaspect
aspect
This
secureTrans,advice
advicebefore
before(line
(line8)
8).
secureTrans,
which
also
crosscuts
in linesource?
10.
Commit
update
to aspect
ARENotice:
Notice:
ARE
ARE Example
T1
Γ2
T2
Γ3
T3 …
Γn
Tn
Method: Store relative coordinate transformation to each
Double-Grafting-Transformation in the weaving sequence
Transposition tree
C. Kessler, IDA, Linköpings universitet.
13
either in the core T0
or
in one of the Γi, i = 1…n
Compute: Source-File + Coordinate of p in Origin of p
Given: Program point coordinate w.r.t. Tn
(row r, column c) in Editor
or, linear index p in Lexeme Sequence (leaf word)
T0
Γ1
Given: Weaving sequence (History)
Problem:
Find Origin of a Program Point
v
w
D
C. Kessler, IDA, Linköpings universitet.
?
C
TE
TB T TD
C
TA
A B
T
E
F
ΓF
Γ
14
G
ΓG
m
r
?
A
v
w
F
p
C
C
G
q
T’
E
T’
T’
F T’ G
T’
A
T’
As example: for a (1,1)-Double-Grafting-Transformation
Transposition Tree Construction (1)
E
15
fposT (v) + |A| - |B| + |F| + |C| - |D| + |G| if v in T’E
fposΓ (v) + |A| - |B| + |F| + |C| if v in T’G
fposT (v) + |A| - |B| + |F| if v in T’C
fposΓ (v) + |A| if v in T’F
fposT (v) if v in T’A
C. Kessler, IDA, Linköpings universitet.
fposT’ (v) =
fsrcT’ (v) =
fsrcT (v) if v in TA, TC, TE
fsrcΓ (v) if v in TF, TG
undefined, if v in TB, TD
Forward-Transposition:
Transposition Tree Construction (2)
A
+0
A
F
B
C. Kessler, IDA, Linköpings universitet.
Ttn(T’)
Ttn(T)
C
-|F|+|B|
C
G
D
E
16
E
F
-|A|-|C|
-|F|-|G|+|B|+|D|
-|A|
Ttn(Γ)
Nodes / Edges in Transposition tree
Backward transposition stored blockwise
All coordinates in the same segment (A, B, …)
are mapped (transposed) in the same way
G
Transposition Tree Construction (3)
e1,1
A
F
F
B
H
e2,3
C
e1,3
C
p
E
e1,5
I
G
e2,5
D
E
C. Kessler, IDA, Linköpings universitet.
17
Search backwards in time O(n)
Data structure needs O(n) space
(Constant depends on k, l)
…
Ttn(T2 ) A
e2,1
Ttn(T1 ) A
Ttn(T0 )
e1,4
G
E
e2,4
H
F
I
G
Input: Coordinate p
v  Ttn ( Tn ); // Ttn for current CST
for t from n downto 1 do
find interval i of p in v (Binary search)
p  Backwardtransp[ et,i ] ( p );
v  target ( et,i );
if v is Ttn of an aspect Γ break
od
e2,2
Ttn(Γ2 )
e1,2
Ttn(Γ1 )
Incremental construction yields tree of depth <= n
Transposition Tree Construction (4)
2 Options (User dialog):
3 Options (User dialog):
C. Kessler, IDA, Linköpings universitet.
18
Store and commit edit as local patch Γn+1
Patch edit directly in Advice (as Γ0 ), then replay Γ1,…,Γn
Commit after Γt for some 0<t<n, then replay Γt+1,…,Γn
Origin in Aspect-Advice
Store and commit edit as local patch Γn+1 of Tn
Patch edit directly in the core (as Γ0 ), then replay Γ1,…,Γn
Origin in core T0
At a change (e.g. edit):
Undo Γn by replaying Γ1,…,Γn-1 on T0
Weaving sequenz can always be replayed
Propagating Changes (1)
Γ2
Γ3
T1
T2
T’3 …
Γ3’
T3 …
C. Kessler, IDA, Linköpings universitet.
19
Limit scope of propagating changes, undo option
Encapsulate inconsistent intermediate configurations
Remedy: Weaving Transactions
T0
Γ1
Γn
Γn’
T’
n’
Tn
Change can lead to disruptive changes in the replay –
code segments created ”later” may disappear, new ones
appear…
Paradox (cf. ”Back to the future II”)
Not all Tt are (semantically) correct programs
Problems:
Propagating Changes (2)
C. Kessler, IDA, Linköpings universitet.
20
Co-Evolution of application core
and woven-in parallelisation code
Sequential application core remains intact
Manual parallelisation (forall, sh, $ivdep, $distribute …)
Semiautomatic transformations (Skeleton expansion)
Rule-based automatic transformations
Planned: Interactive Parallelisation Tool
Application?
C. Kessler, IDA, Linköpings universitet.
21
☺ Space-efficient data structure
☺ Need not know reverse transformation to each step
User dialog for consistent change propagation
Replay
with transposition tree
find origin of a program point
Store weaving sequence
Models static aspect weaving, Macro expansion, Edits …
(k, l )-Double-Grafting-Transformation
Summary
C. Kessler, IDA, Linköpings universitet.
22
Mikhail Chalabine, Christoph Kessler:
A Formal Framework for Automated Round-trip Software Engineering
in Static Aspect Weaving and Transformations,
Proc. of the 29th IEEE / ACM SIGSOFT Int. Conference on Software
Engineering (ICSE 2007), Minneapolis, MN, USA, May 2007
Mikhail Chalabine, Christoph Kessler, Peter Bunus:
Automated Round-trip Software Engineering in Aspect Weaving
Systems (Short paper),
Proc. of the 21st IEEE / ACM International Conference on Automated
Software Engineering (ASE 2006), Tokyo, Japan, September 2006
Uwe Assmann:
Automatic Roundtrip Engineering.
Electronic Lecture Notes in Theoretical Computer Science 85(5), 2003
Uwe Assmann, Andreas Ludwig:
Aspect Weaving by Graph Rewriting.
Proc. Generative Component-Based Software Engineering (GCSE), 1999
References