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CINT & Reflex: New Reflection Data Structures

CINT & Reflex: New Reflection Data Structures. Masa(haru) Goto • Agilent Philippe Canal • Fermilab/CD Stefan Roiser, Axel Naumann • PH/SFT. CINT Is The Prompt, Right?. CINT is Backend for all dictionary based interpreters Execution engine (compiled and interpreted code)

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CINT & Reflex: New Reflection Data Structures

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  1. CINT & Reflex:New Reflection Data Structures Masa(haru) Goto • Agilent Philippe Canal • Fermilab/CD Stefan Roiser, Axel Naumann • PH/SFT

  2. CINT Is The Prompt, Right? CINT is • Backend for all dictionary based interpreters • Execution engine (compiled and interpreted code) • Prerequisite for signal/slot • Prerequisite for I/O Reflection is • Part of CINT’s knowledge, used for all of above • Info on types and their members: name, type, access to values or call AA Review 2006

  3. CINT And Reflection rootcint gccxml Auto-Load C++ Parser Generate Dictionary Reflection Data Interpreter Load Dictionary ROOT Compiled Function Call Uses ReflectionC++ API Dict Gen Data flow AA Review 2006

  4. Comments From Last Review “ Common Linkdef.h interfacerootcint -cint, -reflex, -gccxml Unified Python interface: PyROOT Common Dictionary - unify dictionary clients for experiments using lcgdict/reflex, unify automatic generation of glue code (e.g. python bindings) [JJ Blaising, feedback talk 1.4.2005] AA Review 2006

  5. Dictionary Options – You Choose! Reflex dictionary gccxml parser selection.xml genreflex.py ROOT Cintex Linkdef.h rootcint CINT parser CINT dictionary AA Review 2006

  6. Dictionary Options – The Goal Reflex dictionary gccxml parser selection.xml genreflex.py ROOT Linkdef.h rootcint CINT parser AA Review 2006

  7. “ Ordering, scheduling, priorities [Final Report 2005] Comments From Last Review (cont’ed) First version of Cint with Reflex reflection data base expected for end of year – not yet production grade! Production-grade version available mid 2007 Reasons for delay: • Moving functionality from CINT to Reflex • Keeping CINT API backward compatible • Merge process more involved than expected AA Review 2006

  8. That’s It? Already? No. This talk’s menu offers following courses: • Motivation: why we (still) need the merge • Merge implementation details • Steps of the merge • Merge related development in Cint and Reflex • Status • Outlook AA Review 2006

  9. Motivation For Cint-Reflex Merge C++ code replacing C structs • Smaller heap footprint: factor 3 in current CVS for CLHEP based example – expected to deteriorate • Dynamic data structures, no hard-wired limits • Easier to maintain • Refactoring, separation of functionality • Preparation for thread-safety AA Review 2006

  10. C++ Code Vs. C structs Example Current Cint has global C structs struct G__tagtable { char* name[G__MAXSTRUCT]; … } G__struct; Reflex allows OO access to reflection data Reflex::Scope::GlobalScope(); Covers types, data members, function members, templates,… AA Review 2006

  11. Merge Implementation - Context Why you care: reason for merge schedule • CINT mixes reflection and execution data, need to split carefully • CINT extremely complex: extensive use of globals, spread of functionality, side effects • CINT grown and debugged, don’t want to risk breaking parts that work • Changes need to be “invisible” to users AA Review 2006

  12. Merge Implementation - Consequence • Small step changes • Always compare to working version with extensive test suite • Replace data structures first Major benefit will come only later: • replace functionality • remove code duplication • take advantage of OO data structures AA Review 2006

  13. Steps Of Merge • Need duplication of scope info for both CINT and Reflex while merging (for contained types) • Scaffolding, wrappers, convenience functions for Reflex and CINT • Typedef database: G__newtype Reflex::Type • Globals: G__*tagnum Reflex::Scope • Structs: G__struct  Reflex::Scope • Functions: G__ifunc  Reflex::FunctionMember • Data members: G__vararry  Reflex::DataMember AA Review 2006

  14. Merge Tactics • New configure; make CINT build system to allow sensible multi-platform tests • CVS branch for merge, apply bug fixes from HEAD • All other major development for CINT stalled until merge is done • Update definition of CINT’s API. Will keep API backward compatible, use export statements to ensure no internal function is used by e.g. ROOT • Once done, make libCint.so and libCintNew.so binary compatible, to allow switch without rebuild:mv lib/libCintNew.so lib/libCint.so; root AA Review 2006

  15. Development In CINT For Merge • New build system for standalone CINT/Reflex • API redefinition • Scaffolding to allow transition of data structures without large re-write of code • extern “C” wrappers for some functions and classes + the actual merge… AA Review 2006

  16. Development In Reflex For Merge • Unloading of dictionary • Changes to Reflex::Builder interface • Late (on-demand) initialization of reflection data • Extended C++ support: using directives, hiding typedef struct A A, using declarations, friend • Name Lookup: major boost in Reflex functionality, and damn complex AA Review 2006

  17. Development In Reflex (cont’ed) • Fast access of reflex objects’ properties, needed for CINT execution data • Reflex objects can create dictionary representation of themselves • Several convenience functions, e.g. discover the raw type (const char*  char), the kind of fundamental type etc. AA Review 2006

  18. Status - Where Are We Now? ! struct/class/…, function, data member reflectiondatabase On demand initialization of Reflex data Reflex support for using declarations, friend To Do Duplication of scopes for CINT and Reflex Scaffolding, wrappers, convenience functionality configure && make build system Update of definition of CINT API Typedef, globals reflection database Unloading of dictionary Reflex::Builder interface changes Reflex support for using directives, hiding typedef struct A A Fast access to Reflex objects’ properties ! ! : a lot of work ! Done! ! ! Name Lookup Reflex dictionary generator API On the way AA Review 2006

  19. Outlook - Merge Merge related: • First version of CINT using Reflex by end of year • ROOT’s TClass, TMethod,… classes to be updated after Cint/Reflex merge, i.e. 2007 • Adaptation of PyROOT to use Reflex API • Other ROOT occurrences of CINT API calls to be replaced by Reflex API calls AA Review 2006

  20. Outlook - CINT 2007: • Function stubs / call wrappers will be removed on selected platforms (GCC3,4; MSVC) • Just-in-time dictionary generator builds dictionary for all template instances needed, when needed 2008: • Reflex persistency - .root instead of .so ??? AA Review 2006

  21. Outlook – Dictionary Reflex dictionary gccxml parser genreflex.py Linkdef.h / selection.xml ROOT rootcint CINT parser AA Review 2006

  22. Outlook – Dictionary • Current Reflex dictionaries: • 2007: Remove function stubs on selected platforms • 2007: Generate template dictionaries on demand • 2008: Don’t “store” Reflex database as .cxx/.o (part of lib) but as .root file, generate member offset info on-the-fly: ROOT itself would shrink by ~25%! Improvement independent of selection.xml / Linkdef.h and gendict.py / rootcint 100% 33% ~1% AA Review 2006

  23. Outlook 2008+: • Future: reconsider gccxml to Reflex path: gendict.py? C++? PyROOT based? • CINT thread safety More details in the coming months – early comments welcome! AA Review 2006

  24. FIN AA Review 2006

  25. My.h either / or XML parser (e.g. Xerces) XML parser (e.g. expat) gccxml genreflex.cpp genreflex2.py CINT parser My.xml PyReflex genreflex2 Just in time compiler libMy.so Symbol Lookup Builder API Stub comp. / Offset calc. Linkdef.h / selection.xml ? ROOT Reflex DS My_rflx.root Dictionary Generator genreflex.py meta hist math … Library My_rflx.cpp User API dlopen File Process Data Flow make PyROOT PyReflex CINT interpreter ROOT C/C++ Python >>> cint> libMyRflx.so XML Dictionaries – The Full Picture 200x AA Review 2006

  26. Dictionary Heap Usage CINT, CLHEP example 2500k AA Review 2006

  27. Dictionary Heap Usage Reflex, CLHEP example 700k AA Review 2006

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