Object Flow Analysis

Object Flow Analysis –
Taking an Object-centric View
on Dynamic Analysis

Adrian Lienhard1, Stéphane Ducasse2 and Tudor Gîrba1
1Software Composition Group, University of Bern, Switzerland
2 LISTIC, University of Savoie, France

A missing aspect of OO
dynamic analysis
Typical characterization of OO program execution:
1) message passing
2) object interrelationships

How are objects passed throught the system?

Object Flow Analysis — Taking an Object-centric View on Dynamic Analysis : : Adrian Lienhard : : lienhard@iam.unibe.ch

1) the method execution perspective
MethodNode>>generate
ASTTranslator class>>new
...
...
IRBuilder>>initialize
IRMethod class>>new
...
ASTTranslator>>visitNode:
ASTTranslator>>ir
IRMethod>>compiledMethod
IRTranlator class>new


1) the method execution perspective
...
...
“How is the IRMethod IRMethod class>>new
instance passed to ?
...
MethodNode?” ASTTranslator>>ir
IRTranlator class>new


2) the object interrelationship perspective

:IRMethod :MethodNode

:IRBuilder :IRSequence

:ASTTranslator


2) the object interrelationship perspective

?

“How is the IRMethod :IRMethod :MethodNode

instance passed to
MethodNode?”

:ASTTranslator


... ?
...
IRMethod class>>new

?
...
interdependency?
ASTTranslator>>ir
IRTranlator class>new :ASTTranslator


... ?
...
IRMethod class>>new

?
...
interdependency?
ASTTranslator>>ir
IRTranlator class>new :ASTTranslator

Object Flow Analysis
track the transfer of object references


Object Flow IRBuilder>>initialize
ir := IRMethod new.
instantiation

field store

Analysis
...

IRBuilder>>startNewSequence
newSequence := IRSequence new.
newSequence method: ir. field read

IRSequence>>method: aMethod argument
method := aMethod. field store

a) capture all
ASTTranslator>>ir
^ builder ir. return

references of an MethodNode>>generate

object ast := ASTTranslator new visitNode: self.
ir := ast ir. return
^ ir compiledMethod. field store
field read

b) track the IRMethod>>compiledMethod
^ compiledMethod := IRTranslator new
transfer of interpret: self;
compiledMethod.
references IRTranslator>>interpret: ir argument
...


ir := IRMethod new.
instantiation
instantiation
field write
field write

Analysis
...


method := aMethod. field write

a) capture all
ASTTranslator>>ir
^ builder ir. return return

references of an MethodNode>>generate

object ast := ASTTranslator new visitNode: self.
ir := ast ir. return return
^ ir compiledMethod. field write field write
field read field read

b) track the IRMethod>>compiledMethod
transfer of interpret: self;
compiledMethod.
references IRTranslator>>interpret: ir argumentargument
...


ir := IRMethod new.
instantiation
instantiation
field store
write
field write
1

Analysis
... 1

2 2
write

“How is the IRMethod
ASTTranslator>>ir
^ builder ir. return return

instance passed to 3
3

MethodNode?” ast := ASTTranslator new visitNode: self.
ir := ast ir. return return
^ ir compiledMethod. field write field write
store
field read field read
interpret: self;
compiledMethod.

IRTranslator>>interpret: ir argumentargument
...


Application

How do classes
exchange objects?


Inter-unit
ﬂow view


Inter-unit
ﬂow view
classes
containedInPackage: ʼAST-Nodesʼ
mapTo: ʼASTʼ.

classes
hierarchyRootedIn: ʼIRInstructionʼ
mapTo: ʼIntermediate-Representationʼ


Chronological
propagation


Parser (4)

Spanning ﬂows


Spanning ﬂows

IRBuilder


timeline

objects created in
IRBuilder

timeline

objects passed
through directly

timeline

objects stored
in an instance
variable

timeline

objects passed out
multiple times

timeline

Representing object flows
IRBuilder>>initialize instantiation
ir := IRMethod new.
... field store
write


write

ASTTranslator>>ir

ast := ASTTranslator new visitNode: self.
return
ir := ast ir.
field store
^ ir compiledMethod.
field read
...


ir := IRMethod new. Instance
... field store
write

field read parent
newSequence method: ir. 0..1
Alias
*
write
child
ASTTranslator>>ir

return
ir := ast ir.
field store
field read
...


instantiation
Instance
field store
write

field read parent
0..1
Alias
argument
*
field store
write
child

return
... ArgumentAlias ReturnAlias FieldWriteAlias

self.
return
field store
field read
...


n
Instance Class

sender
parent 0..1 *
0..1 receiver
Alias Activation Method
*
child creator
Attribute

turn

turn
store
d read
...


Summary
ir := IRMethod new. Instance Class
... field store
write

IRBuilder>>startNewSequence sender
newSequence := IRSequence new. 0..1
field read parent *
newSequence method: ir. 0..1 receiver
*
store creator
child
Attribute
ASTTranslator>>ir
return
ir := ast ir.
field store
field read
...


Summary
ir := IRMethod new. Instance Class
... field store
write

IRBuilder>>startNewSequence sender
newSequence := IRSequence new. 0..1
field read parent *
newSequence method: ir. 0..1 receiver
*
store creator
child
Attribute
ASTTranslator>>ir
return
ir := ast ir.
field store
field read
...

Questions?


Object Flow Analysis

Recommended

Recommended

More Related Content

Viewers also liked

Viewers also liked (19)

More from lienhard

More from lienhard (10)

Recently uploaded

Recently uploaded (20)

Object Flow Analysis