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Object-Centric Debugging: a preview
The document discusses object-centric debugging which allows debugging operations at the level of individual objects. Object-centric breakpoints allow halting execution based on message sends or state access for a specific object. Object-centric behavior allows dynamically adding methods to a single object. The implementation uses techniques like reflectivity, proxies, and anonymous classes but currently lacks a clear model. Problems include needing to migrate objects and unstable tools. Part II previews a reverse object-centric debugger being developed collaboratively.
Object-Centric Debugging: a preview
- 1. Object-Centric Debugging: apreview Steven Costiou steven.costiou@inria.fr RMoD Inria Lille - Nord Europe 2019
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- 5. What is object-centricdebugging? 5
- 6. Object-centric debugging • Debuggingoperations at the level of objects • Only target objects are affected • Examples: • A breakpoint active for one object only • A method available for one object only 6
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- 8. Why Object-centric debugging? •Debugging one object among many: • Collections (Hinkle, Jones, Johnson, 1993) • Events • Graphical objects 8
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- 10. Object-centric breakpoints • Breakwhen a message is received • haltOnCall => on every method call • haltOnCall: #selector => for given selector only • haltOnNextCall => on next method call • haltOnceOnCall: #selector => only once for given selector • haltOnCallWhen: condition => if condition is met 10
- 11. Object-centric breakpoints • Breakon state access • haltOnWriteTo: #instVarName => when instVarName is written • haltOnRead: #instVarName => when instVarName is read • haltOnWrite => when any instance variable is written • haltOnRead => when any instance variable is read 11
- 12. Object-centric behavior • Object-centricmethods • compile: sourceCode => compiles and add new methods • uses: aTrait => acquires behavior from Trait • acquire: aCompiledMethod => acquire the method 12
- 13. Object-centric debugging, how isit implemented? 13
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- 19. Implementation goal 19 Reflectivity ProxiesTalents Anonymous Classes Object-centric breakpoints Object-centric behavior Object-centric layer Object-centric …
- 20. Current problems • Implementationis mixing up different techniques without any clear interaction model • Requires to migrate the object to an anonymous subclass • Installation of object-centric instrumentation is not thread-safe • Sometimes make tools unstable • Obtaining objects to debug (but work has been done on that…) 20
- 21. Part II Object-Centric ReverseDebugging 21
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- 34. Reverse object-centric debugger •AST interpreter - Carolina Hernandez Phillips • Reverse-execution - Vincent Aranega, Steven Costiou • Object-centric debugger - Steven Costiou • Scriptable debugger - Thomas Dupriez 34 Who’s working on it?
- 35. Thanks! Questions? 35 Object-Centric Reverse Debugging Object-Centric Debugging •haltOnCall • haltOnCall: #selector • haltOnNextCall • haltOnceOnCall: #selector • haltOnCallWhen: condition • haltOnWriteTo: #instVarName • haltOnRead: #instVarName • haltOnWrite • haltOnRead • compile: sourceCode • uses: aTrait • acquire: aCompiledMethod