Pointer Analysis in 10 Rules

Everything you need to know about Pointer Analysis in 10 Rules. Presentation for the 10th annual PL-seminar of http://www.softlab.ntua.gr/

Transcript

1. POINTER ANALYSIS EVERYTHING YOU NEED TO KNOW ABOUT 10 RULES George Kastrinis ~ University of Athens ~ PLAST lab
2. BASED ON WORK FROM • “Efficient and Effective Handling of Exceptions in Java Points-To Analysis” Kastrinis G., Smaragdakis Y. (CC'13) • “Pick Your Contexts Well: Understanding Object-Sensitivity” Smaragdakis Y., Bravenboer M., Lhoták O. (POPL'11) • “Strictly Declarative Specification of Sophisticated Points-to Analyses” Bravenboer M., Smaragdakis Y. (OOPSLA'09) University of Athens ~ PL lab (PLAST) Yannis Smaragdakis George Kastrinis George Balatsouras Aggelos Biboudis Kostas Ferles George Kollias Prodromos Gerakios George Kastrinis ~ University of Athens ~ PLAST lab
3. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? George Kastrinis ~ University of Athens ~ PLAST lab
4. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } George Kastrinis ~ University of Athens ~ PLAST lab
5. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → George Kastrinis ~ University of Athens ~ PLAST lab
6. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → Represent objects as allocation sites George Kastrinis ~ University of Athens ~ PLAST lab
7. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a new A1(), new A2() → George Kastrinis ~ University of Athens ~ PLAST lab
8. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a new A1(), new A2() → foo::b new A1(), new A2() → bar::b new A1(), new A2() → George Kastrinis ~ University of Athens ~ PLAST lab
9. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a new A1(), new A2() → foo::b new A1(), new A2() → bar::b new A1(), new A2() → Not the most precise, right? George Kastrinis ~ University of Athens ~ PLAST lab
10. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a new A1(), new A2() → George Kastrinis ~ University of Athens ~ PLAST lab
11. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a new A1(), new A2() → Add “context” to variables George Kastrinis ~ University of Athens ~ PLAST lab
12. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a (foo) new A1() → id::a (bar) new A2() → Add “context” to variables George Kastrinis ~ University of Athens ~ PLAST lab
13. IN SHORT: WHAT OBJECTS CAN A VARIABLE POINT TO? void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a (foo) new A1() → id::a (bar) new A2() → foo::b new A1() → bar::b new A2() → Add “context” to variables George Kastrinis ~ University of Athens ~ PLAST lab
14. 10 RULES? NO ALGORITHMS? George Kastrinis ~ University of Athens ~ PLAST lab
15. 10 RULES? NO ALGORITHMS? Using Datalog George Kastrinis ~ University of Athens ~ PLAST lab
16. 10 RULES? NO ALGORITHMS? Using Datalog Purely declarative George Kastrinis ~ University of Athens ~ PLAST lab
17. de·clar·a·tive /di kle( )r tiv/ ˈ ə ə Computing denoting high-level programming languages which can be used to solve problems without requiring the programmer to specify an exact procedure to be followed. Adjective ~ Oxford dictionaries George Kastrinis ~ University of Athens ~ PLAST lab
18. de·clar·a·tive /di kle( )r tiv/ ˈ ə ə Computing denoting high-level programming languages which can be used to solve problems without requiring the programmer to specify an exact procedure to be followed. Adjective ~ Oxford dictionaries From algorithms to specifications George Kastrinis ~ University of Athens ~ PLAST lab
19. Datalog Rules INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). George Kastrinis ~ University of Athens ~ PLAST lab
20. Datalog Rules INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). head George Kastrinis ~ University of Athens ~ PLAST lab
21. Datalog Rules INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). body George Kastrinis ~ University of Athens ~ PLAST lab
22. Datalog Rules INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). Output relations in red George Kastrinis ~ University of Athens ~ PLAST lab
23. Datalog Rules INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). Input relations in blue George Kastrinis ~ University of Athens ~ PLAST lab
24. Datalog Rules INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). #1 meth(..,from,..) George Kastrinis ~ University of Athens ~ PLAST lab
25. Datalog Rules #1 invo: meth(..,from,..) meth(..,to,..) { ... } callerCtx calleeCtx INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). meth(..,from,..) George Kastrinis ~ University of Athens ~ PLAST lab
26. Datalog Rules #1 invo: meth(..,from,..) meth(..,to,..) { ... } INTERPROCASSIGN(to, calleeCtx, from, callerCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALARG(invo, i, from), FORMALARG(meth, i, to). meth(..,from,..) callerCtx calleeCtx George Kastrinis ~ University of Athens ~ PLAST lab
27. Datalog Rules INTERPROCASSIGN(to, callerCtx, from, calleeCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALRETURN(invo, to), FORMALRETURN(meth, from). #2 to = meth(..) George Kastrinis ~ University of Athens ~ PLAST lab
28. Datalog Rules INTERPROCASSIGN(to, callerCtx, from, calleeCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALRETURN(invo, to), FORMALRETURN(meth, from). #2 to = meth(..) invo: to = meth(..) meth(..) { .. return from; } callerCtx calleeCtx George Kastrinis ~ University of Athens ~ PLAST lab
29. Datalog Rules INTERPROCASSIGN(to, callerCtx, from, calleeCtx) ← CALLGRAPH(invo, callerCtx, meth, calleeCtx), ACTUALRETURN(invo, to), FORMALRETURN(meth, from). #2 to = meth(..) invo: to = meth(..) meth(..) { .. return from; } calleeCtx callerCtx George Kastrinis ~ University of Athens ~ PLAST lab
30. Datalog Rules RECORD(heap, ctx) = hctx, VARPOINTSTO(var, ctx, heap, hctx) ← REACHABLE(meth, ctx), ALLOC(var, heap, meth). #3 var = new A() George Kastrinis ~ University of Athens ~ PLAST lab
31. Datalog Rules RECORD(heap, ctx) = hctx, VARPOINTSTO(var, ctx, heap, hctx) ← REACHABLE(meth, ctx), ALLOC(var, heap, meth). #3 var = new A() meth var = new A(); ctx heap George Kastrinis ~ University of Athens ~ PLAST lab
32. Datalog Rules RECORD(heap, ctx) = hctx, VARPOINTSTO(var, ctx, heap, hctx) ← REACHABLE(meth, ctx), ALLOC(var, heap, meth). #3 var = new A() meth var = new A(); heap hctx new context! ctx George Kastrinis ~ University of Athens ~ PLAST lab
33. Datalog Rules RECORD(heap, ctx) = hctx, VARPOINTSTO(var, ctx, heap, hctx) ← REACHABLE(meth, ctx), ALLOC(var, heap, meth). #3 var = new A() meth var = new A(); heap hctx ctx George Kastrinis ~ University of Athens ~ PLAST lab
34. Datalog Rules VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), MOVE(to, from). #4 to = from George Kastrinis ~ University of Athens ~ PLAST lab
35. Datalog Rules VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), MOVE(to, from). #4 to = from heap hctx from ctx George Kastrinis ~ University of Athens ~ PLAST lab
36. Datalog Rules VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), MOVE(to, from). #4 to = from heap hctx from ctx to George Kastrinis ~ University of Athens ~ PLAST lab
37. Datalog Rules VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), MOVE(to, from). #4 to = from heap hctx from ctx to ctx George Kastrinis ~ University of Athens ~ PLAST lab
38. Datalog Rules VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), MOVE(to, from). #4 to = from Recursion! George Kastrinis ~ University of Athens ~ PLAST lab
39. Datalog Rules #5 to ≈ from VARPOINTSTO(to, toCtx, heap, hctx) ← INTERPROCASSIGN(to, toCtx, from, fromCtx), VARPOINTSTO(from, fromCtx, heap, hctx). George Kastrinis ~ University of Athens ~ PLAST lab
40. Datalog Rules #5 to ≈ from VARPOINTSTO(to, toCtx, heap, hctx) ← INTERPROCASSIGN(to, toCtx, from, fromCtx), VARPOINTSTO(from, fromCtx, heap, hctx). from fromCtx to toCtx George Kastrinis ~ University of Athens ~ PLAST lab
41. Datalog Rules #5 to ≈ from VARPOINTSTO(to, toCtx, heap, hctx) ← INTERPROCASSIGN(to, toCtx, from, fromCtx), VARPOINTSTO(from, fromCtx, heap, hctx). from fromCtx to toCtx heap hctx George Kastrinis ~ University of Athens ~ PLAST lab
42. Datalog Rules #5 to ≈ from VARPOINTSTO(to, toCtx, heap, hctx) ← INTERPROCASSIGN(to, toCtx, from, fromCtx), VARPOINTSTO(from, fromCtx, heap, hctx). from fromCtx to toCtx heap hctx George Kastrinis ~ University of Athens ~ PLAST lab
43. Datalog Rules #6 base.fld = from FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), STORE(base, fld, from), VARPOINTSTO(base, ctx, baseH, baseHCtx). George Kastrinis ~ University of Athens ~ PLAST lab
44. Datalog Rules #6 base.fld = from heap hctx from ctx FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), STORE(base, fld, from), VARPOINTSTO(base, ctx, baseH, baseHCtx). George Kastrinis ~ University of Athens ~ PLAST lab
45. Datalog Rules #6 base.fld = from heap hctx from ctx base ctx FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), STORE(base, fld, from), VARPOINTSTO(base, ctx, baseH, baseHCtx). fld George Kastrinis ~ University of Athens ~ PLAST lab
46. Datalog Rules #6 base.fld = from heap hctx from ctx base ctx FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), STORE(base, fld, from), VARPOINTSTO(base, ctx, baseH, baseHCtx). fld baseH baseHCtx George Kastrinis ~ University of Athens ~ PLAST lab
47. Datalog Rules #6 base.fld = from heap hctx from ctx base ctx FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx) ← VARPOINTSTO(from, ctx, heap, hctx), STORE(base, fld, from), VARPOINTSTO(base, ctx, baseH, baseHCtx). fld baseH baseHCtx fld George Kastrinis ~ University of Athens ~ PLAST lab
48. Datalog Rules #7 to = base.fld VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(base, ctx, baseH, baseHCtx), FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx), LOAD(to, base, fld). George Kastrinis ~ University of Athens ~ PLAST lab
49. Datalog Rules #7 to = base.fld VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(base, ctx, baseH, baseHCtx), FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx), LOAD(to, base, fld). base ctx baseH baseHCtx George Kastrinis ~ University of Athens ~ PLAST lab
50. Datalog Rules #7 to = base.fld VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(base, ctx, baseH, baseHCtx), FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx), LOAD(to, base, fld). base ctx baseH baseHCtx fld heap hctx George Kastrinis ~ University of Athens ~ PLAST lab
51. Datalog Rules #7 to = base.fld VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(base, ctx, baseH, baseHCtx), FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx), LOAD(to, base, fld). base ctx baseH baseHCtx fld heap hctx to fld George Kastrinis ~ University of Athens ~ PLAST lab
52. Datalog Rules #7 to = base.fld VARPOINTSTO(to, ctx, heap, hctx) ← VARPOINTSTO(base, ctx, baseH, baseHCtx), FLDPOINTSTO(baseH, baseHCtx, fld, heap, hctx), LOAD(to, base, fld). base ctx baseH baseHCtx fld to fld ctx heap hctx George Kastrinis ~ University of Athens ~ PLAST lab
53. Datalog Rules #8 A::toMeth() MERGESTATIC(invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← SCALL(toMeth, invo, inMeth), REACHABLE(inMeth, callerCtx). George Kastrinis ~ University of Athens ~ PLAST lab
54. Datalog Rules #8 A::toMeth() MERGESTATIC(invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← SCALL(toMeth, invo, inMeth), REACHABLE(inMeth, callerCtx). invo: A::toMeth(..) inMeth callerCtx toMeth George Kastrinis ~ University of Athens ~ PLAST lab
55. Datalog Rules #8 A::toMeth() MERGESTATIC(invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← SCALL(toMeth, invo, inMeth), REACHABLE(inMeth, callerCtx). invo: A::toMeth(..) inMeth callerCtx toMeth callerCtx new context! George Kastrinis ~ University of Athens ~ PLAST lab
56. Datalog Rules #8 A::toMeth() MERGESTATIC(invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← SCALL(toMeth, invo, inMeth), REACHABLE(inMeth, callerCtx). invo: A::toMeth(..) inMeth callerCtx toMeth calleeCtx George Kastrinis ~ University of Athens ~ PLAST lab
57. Datalog Rules #9 MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). base.sig(..) ! ! George Kastrinis ~ University of Athens ~ PLAST lab
58. Datalog Rules #9 MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). base.sig(..) ! ! invo: base.sig(..) inMeth callerCtx George Kastrinis ~ University of Athens ~ PLAST lab
59. George Kastrinis ~ University of Athens ~ PLAST lab Datalog Rules #9 MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). base.sig(..) ! ! invo: base.sig(..) inMeth callerCtx heap hctx
60. George Kastrinis ~ University of Athens ~ PLAST lab Datalog Rules #9 MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). base.sig(..) ! ! invo: base.sig(..) inMeth callerCtx heap hctx this toMeth
61. George Kastrinis ~ University of Athens ~ PLAST lab Datalog Rules #9 MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). base.sig(..) ! ! invo: base.sig(..) inMeth callerCtx heap hctx this toMeth calleeCtx new context!
62. George Kastrinis ~ University of Athens ~ PLAST lab Datalog Rules #9 MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). base.sig(..) ! ! invo: base.sig(..) inMeth callerCtx heap hctx this toMeth calleeCtx
63. George Kastrinis ~ University of Athens ~ PLAST lab Datalog Rules #9 MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). base.sig(..) ! ! invo: base.sig(..) inMeth callerCtx heap hctx this toMeth calleeCtx
64. Datalog Rules #10 George Kastrinis ~ University of Athens ~ PLAST lab
65. Datalog Rules #10 9 RULES ARE ENOUGH! George Kastrinis ~ University of Athens ~ PLAST lab
66. Variety of Analyses George Kastrinis ~ University of Athens ~ PLAST lab
67. Variety of Analyses Just alter the definition of “context” George Kastrinis ~ University of Athens ~ PLAST lab
68. LET'S RECALL WHERE CONTEXTS ARE CREATED George Kastrinis ~ University of Athens ~ PLAST lab
69. RECORD(heap, ctx) = hctx, VARPOINTSTO(var, ctx, heap, hctx) ← REACHABLE(meth, ctx), ALLOC(var, heap, meth). MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). MERGESTATIC(invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← SCALL(toMeth, invo, inMeth), REACHABLE(inMeth, callerCtx). #3 #8 #9 LET'S RECALL WHERE CONTEXTS ARE CREATED George Kastrinis ~ University of Athens ~ PLAST lab
70. RECORD(heap, ctx) = hctx, VARPOINTSTO(var, ctx, heap, hctx) ← REACHABLE(meth, ctx), ALLOC(var, heap, meth). MERGE(heap, hctx, invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), VARPOINTSTO(this, calleeCtx, heap, hctx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← REACHABLE(inMeth, callerCtx), VCALL(base, sig, invo, inMeth), VARPOINTSTO(base, callerCtx, heap, hctx), HEAPTYPE(heap, heapT), LOOKUP(heapT, sig, toMeth), THISVAR(toMeth, this). MERGESTATIC(invo, callerCtx) = calleeCtx, REACHABLE(toMeth, calleeCtx), CALLGRAPH(invo, callerCtx, toMeth, calleeCtx) ← SCALL(toMeth, invo, inMeth), REACHABLE(inMeth, callerCtx). #3 #8 #9 LET'S RECALL WHERE CONTEXTS ARE CREATED George Kastrinis ~ University of Athens ~ PLAST lab Method invocation Object allocation
71. CONTEXT INSENSITIVE IGNORE CONTEXT ALTOGETHER George Kastrinis ~ University of Athens ~ PLAST lab
72. CONTEXT INSENSITIVE IGNORE CONTEXT ALTOGETHER void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a new A1(), new A2() → foo::b new A1(), new A2() → bar::b new A1(), new A2() → George Kastrinis ~ University of Athens ~ PLAST lab
73. CONTEXT INSENSITIVE IGNORE CONTEXT ALTOGETHER RECORD(heap, ctx) = * MERGE(heap, hctx, invo, callerCtx) = * MERGESTATIC(invo, callerCtx) = * Use a single context everywhere! George Kastrinis ~ University of Athens ~ PLAST lab
74. CALL-SITE SENSITIVITY USE CALL-SITES AS CONTEXTS George Kastrinis ~ University of Athens ~ PLAST lab
75. CALL-SITE SENSITIVITY USE CALL-SITES AS CONTEXTS void foo() { a = new A1(); b = id(a); } void bar() { a = new A2(); b = id(a); } A id(A a) { return a; } foo::a new A1() → bar::a new A2() → id::a (inv1) new A1() → id::a (inv2) new A2() → foo::b new A1() → bar::b new A2() → inv1 inv2 George Kastrinis ~ University of Athens ~ PLAST lab
76. 1-CALL-SITE SENSITIVE Context's depth George Kastrinis ~ University of Athens ~ PLAST lab
77. 1-CALL-SITE SENSITIVE RECORD(heap, ctx) = * No context for heap abstractions George Kastrinis ~ University of Athens ~ PLAST lab
78. 1-CALL-SITE SENSITIVE RECORD(heap, ctx) = * MERGE(heap, hctx, invo, callerCtx) = invo MERGESTATIC(invo, callerCtx) = invo George Kastrinis ~ University of Athens ~ PLAST lab
79. 1-CALL-SITE SENSITIVE+1-HEAP Context sensitive heap abstractions George Kastrinis ~ University of Athens ~ PLAST lab
80. 1-CALL-SITE SENSITIVE+1-HEAP RECORD(heap, ctx) = ctx George Kastrinis ~ University of Athens ~ PLAST lab
81. 1-CALL-SITE SENSITIVE+1-HEAP RECORD(heap, ctx) = ctx MERGE(heap, hctx, invo, callerCtx) = invo MERGESTATIC(invo, callerCtx) = invo George Kastrinis ~ University of Athens ~ PLAST lab
82. OBJECT SENSITIVITY USE ALLOCATION-SITES AS CONTEXTS George Kastrinis ~ University of Athens ~ PLAST lab
83. OBJECT SENSITIVITY USE ALLOCATION-SITES AS CONTEXTS Based on the receiver object in a method call George Kastrinis ~ University of Athens ~ PLAST lab
84. OBJECT SENSITIVITY USE ALLOCATION-SITES AS CONTEXTS Really good for Object-Oriented languages George Kastrinis ~ University of Athens ~ PLAST lab
85. OBJECT SENSITIVITY USE ALLOCATION-SITES AS CONTEXTS class C { void meth(Object o) { ... } } class Client { void bar(C c1, C c2) { ... c1.meth(obj1); ... c2.meth(obj2); } } George Kastrinis ~ University of Athens ~ PLAST lab
86. OBJECT SENSITIVITY USE ALLOCATION-SITES AS CONTEXTS class C { void meth(Object o) { ... } } class Client { void bar(C c1, C c2) { ... c1.meth(obj1); ... c2.meth(obj2); } } #contexts for meth::o? George Kastrinis ~ University of Athens ~ PLAST lab
87. OBJECT SENSITIVITY USE ALLOCATION-SITES AS CONTEXTS class C { void meth(Object o) { ... } } class Client { void bar(C c1, C c2) { ... c1.meth(obj1); ... c2.meth(obj2); } } #contexts for meth::o? #objects (and which) c1 and c2 point to? George Kastrinis ~ University of Athens ~ PLAST lab
88. 1-OBJECT SENSITIVE RECORD(heap, ctx) = * No context for heap abstractions George Kastrinis ~ University of Athens ~ PLAST lab
89. 1-OBJECT SENSITIVE RECORD(heap, ctx) = * MERGE(heap, hctx, invo, callerCtx) = heap Use the allocation-site of the receiver object George Kastrinis ~ University of Athens ~ PLAST lab
90. 1-OBJECT SENSITIVE RECORD(heap, ctx) = * MERGE(heap, hctx, invo, callerCtx) = heap MERGESTATIC(invo, callerCtx) = ctx No receiver object to use! George Kastrinis ~ University of Athens ~ PLAST lab
91. 1-OBJECT SENSITIVE RECORD(heap, ctx) = * MERGE(heap, hctx, invo, callerCtx) = heap MERGESTATIC(invo, callerCtx) = ctx No receiver object to use! Copy context from caller George Kastrinis ~ University of Athens ~ PLAST lab
92. AND NOW? George Kastrinis ~ University of Athens ~ PLAST lab
93. AND NOW? • DIFFERENT CONTEXT DEPTHS George Kastrinis ~ University of Athens ~ PLAST lab
94. AND NOW? • DIFFERENT CONTEXT DEPTHS • ALTER DEFINITIONS OF RECORD AND MERGE George Kastrinis ~ University of Athens ~ PLAST lab
95. AND NOW? • DIFFERENT CONTEXT DEPTHS • ALTER DEFINITIONS OF RECORD AND MERGE • OTHER TYPES OF CONTEXT George Kastrinis ~ University of Athens ~ PLAST lab
96. AND NOW? • DIFFERENT CONTEXT DEPTHS • ALTER DEFINITIONS OF RECORD AND MERGE • OTHER TYPES OF CONTEXT • COMBINE DIFFERENT CONTEXTS George Kastrinis ~ University of Athens ~ PLAST lab
97. AND NOW? • DIFFERENT CONTEXT DEPTHS • ALTER DEFINITIONS OF RECORD AND MERGE • OTHER TYPES OF CONTEXT • COMBINE DIFFERENT CONTEXTS What to combine? Where? How? George Kastrinis ~ University of Athens ~ PLAST lab
98. 9 Rules 3 Context Functions x = ∞ Analyses RECAP George Kastrinis ~ University of Athens ~ PLAST lab
99. Hope you enjoyed! http://gkastrinis.info George Kastrinis •