method George Kastrinis , Yannis Smaragdakis ~ Efficient and - PowerPoint PPT Presentation

E FFICIENT AND E FFECTIVE H ANDLING OF E XCEPTIONS IN J AVA P OINTS- T O A NALYSIS George Kastrinis ~ Yannis Smaragdakis University of Athens

E XECUTIVE S UMMARY ● Huge amount of analysis time spent on exceptions ● They mainly affect control-flow ● Significant speedup from coarsening exceptions ● Type-based merging as an effective coarsening ● No trade-off in precision (in “normal” code) ● Datalog formalism makes changes clear ● Also excellent implementation platform George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E FFICIENT AND E FFECTIVE H ANDLING OF E XCEPTIONS IN J AVA P OINTS- T O A NALYSIS George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E FFICIENT AND E FFECTIVE H ANDLING OF E XCEPTIONS IN J AVA P OINTS- T O A NALYSIS What objects may a variable point to? (statically, object = allocation site) George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E FFICIENT AND E FFECTIVE H ANDLING OF E XCEPTIONS IN J AVA P OINTS- T O A NALYSIS George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

R EFRESHER ON E XCEPTIONS void foo (...) throws AnException { try { ... throw new MyException(); ... } catch (OtherException e) { ... } } George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

S IGNIFICANCE OF E XCEPTIONS ● Exceptions are non-local control flow ● They are also regular objects with data fields ● How significant is the data-flow of exceptions? ● Our research indirectly answers this George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

F LOW O F O BJECTS method George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

N ORMAL F LOW O F O BJECTS arguments method return George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E XCEPTIONAL F LOW O F O BJECTS arguments method return throw George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

Normal Flow arguments method VS return throw Exceptional Flow George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

Normal Flow Exceptional Flow VS Which one do you think dominates? ● i.e., for the average method are there more objects that may be thrown out of it or that may be passed into/out of it as args/returns? George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

Normal Flow Exceptional Flow VS Which one do you think dominates? normal flow exceptional flow George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

N EED P RECISE E XCEPTIONS ? George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

N EED P RECISE E XCEPTIONS ? Not per se George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

N EED P RECISE E XCEPTIONS ? Not per se Overall analysis effect George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

C OARSEN E XCEPTIONS A. Context Insensitive George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

C OARSEN E XCEPTIONS A. Context Insensitive B. Type-based Merging George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E FFICIENT AND E FFECTIVE H ANDLING OF E XCEPTIONS IN J AVA P OINTS- T O A NALYSIS George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E FFICIENT AND E FFECTIVE H ANDLING OF E XCEPTIONS IN J AVA P OINTS- T O A NALYSIS George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

I NPUT George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

J AVA C ODE v = new A(); to = from; to = base.fld; base.fld = from; void meth(..., A arg, ...) { ... return ret; } base.sig(...); George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

J AVA C ODE AS T ABLES A LLOC ( var, obj, meth ) v = new A(); O BJ T YPE ( obj, type ) to = from; M OVE ( to, from ) to = base.fld; L OAD ( to, base, fld ) base.fld = from; S TORE ( base, fld, from ) void meth(..., A arg, ...) { F ORMAL A RG ( meth, i, arg ) ... F ORMAL R ETURN ( meth, ret ) return ret; } VC ALL ( base, sig, invo ) base.sig(...); George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

J AVA C ODE AS T ABLES A LLOC ( var, obj, meth ) v = new A(); O BJ T YPE ( obj, type ) to = from; M OVE ( to, from ) to = base.fld; L OAD ( to, base, fld ) base.fld = from; S TORE ( base, fld, from ) void meth(..., A arg, ...) { F ORMAL A RG ( meth, i, arg ) ... F ORMAL R ETURN ( meth, ret ) return ret; } VC ALL ( base, sig, invo ) base.sig(...); George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

J AVA C ODE AS T ABLES A LLOC ( var, obj, meth ) v = new A(); O BJ T YPE ( obj, type ) to = from; M OVE ( to, from ) to = base.fld; L OAD ( to, base, fld ) base.fld = from; S TORE ( base, fld, from ) void meth(..., A arg, ...) { F ORMAL A RG ( meth, i, arg ) ... F ORMAL R ETURN ( meth, ret ) return ret; } VC ALL ( base, sig, invo ) base.sig(...); and many more... George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

J AVA C ODE AS T ABLES A LLOC ( var, obj, meth ) v = new A(); O BJ T YPE ( obj, type ) Blue is Input to = from; M OVE ( to, from ) to = base.fld; L OAD ( to, base, fld ) base.fld = from; S TORE ( base, fld, from ) void meth(..., A arg, ...) { F ORMAL A RG ( meth, i, arg ) ... F ORMAL R ETURN ( meth, ret ) return ret; } VC ALL ( base, sig, invo ) base.sig(...); and many more... George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

O UTPUT George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

O UTPUT most important... V AR P OINTS T O ( var, ctx, obj, objCtx ) George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

O UTPUT most important... V AR P OINTS T O ( var, ctx, obj, objCtx ) R EACHABLE ( meth, ctx ) C ALL G RAPH ( invo, callerCtx, meth, calleeCtx ) “On the fly” construction George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

O UTPUT most important... V AR P OINTS T O ( var, ctx, obj, objCtx ) R EACHABLE ( meth, ctx ) Orange is Output C ALL G RAPH ( invo, callerCtx, meth, calleeCtx ) “On the fly” construction George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

C ONTEXTS : B LACK B OX V AR P OINTS T O ( var, ctx, obj, objCtx ) R EACHABLE ( meth, ctx ) C ALL G RAPH ( invo, callerCtx, meth, calleeCtx ) George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

C ONTEXTS C ONSTRUCTORS V AR P OINTS T O ( var, ctx, obj, objCtx ) R EACHABLE ( meth, ctx ) C ALL G RAPH ( invo, callerCtx, meth, calleeCtx ) R ECORD ( ... ) = newObjCtx Pick Your Contexts Well: Understanding Object-Sensitivity M ERGE ( ... ) = newCtx Smaragdakis – Bravenboer – Lhotak POPL'11 George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

R ULES George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E XAMPLE R ULE ← R ( x, y, w ), S ( y, z ). P ( x ), Q ( x, z ) George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E XAMPLE R ULE P ( x ), Q ( x, z ) ← R ( x, y, w ), S ( y, z ). If... “Body” George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

E XAMPLE R ULE “Head” Then... ← R ( x, y, w ), S ( y, z ). P ( x ), Q ( x, z ) If... “Body” George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

O BJECT A LLOCATION var = new ... R EACHABLE ( meth, ctx ), A LLOC ( var, obj, meth ). George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis

O BJECT A LLOCATION var = new ... V AR P OINTS T O ( var, obj ) ← R EACHABLE ( meth, ctx ), A LLOC ( var, obj, meth ). George Kastrinis , Yannis Smaragdakis ~ Efficient and Effective Handling of Exceptions in Java Points-To Analysis