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Cling’s Context, Status and Plans
Prototype of ROOT’s new Interpreter and Reflection Database
Axel Naumann, 2011-03-14
Timetable
9:05 Motivation for cling 9:10 Context for a new interpreter 9:20 Status 9:25 Plans
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Clings Context, Status and Plans Prototype of ROOTs new Interpreter - - PowerPoint PPT Presentation
Clings Context, Status and Plans Prototype of ROOTs new Interpreter - - PowerPoint PPT Presentation
Clings Context, Status and Plans Prototype of ROOTs new Interpreter and Reflection Database Axel Naumann, 2011-03-14 Timetable 9:05 Motivation for cling 9:10 Context for a new interpreter 9:20 Status 9:25 Plans 2 Motivation 3
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Motivation
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Motivation
Deficiencies of CINT now relevant: Correctness C++ support, also C++ 1x Speed Maintenance
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Why cling
cling based on open source compiler llvm / clang Correctness C++ support, also c++ 1x Speed Maintenance
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Why cling
cling based on open source compiler llvm / clang Correctness C++ support, also c++ 1x Speed Maintenance
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Why cling
cling based on open source compiler llvm / clang Correctness C++ support, also c++ 1x Speed Maintenance
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Why cling
cling based on open source compiler llvm / clang Correctness C++ support, also c++ 1x Speed Maintenance
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Why cling
cling based on open source compiler llvm / clang Correctness C++ support, also c++ 1x Speed Maintenance
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Context
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Context
BACKWARD COMPATIBILITY! CINT features, C++ extensions ROOT Reflection & I/O: TCint, TClass Dictionaries: selection.xml, Linkdef.h Reflex
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CINT features, ++C++
Dynamic scope: Un- / Reloading: #includes, library loading, variable declaration: all implicit
new ¡TFile(“h.root”); hist-‑>Draw(); .x mycode.C //edit .x mycode.C
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ROOT Reflection
Interface to CINT is TCint; re-implement using cling/clang/llvm Proper overload resolution (signal/ slot etc) Will allow full access to C++ through ROOT (enum, ...) Simplifies dictionaries (shadow,...)
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ROOT Reflection (2)
Reflection database: clang abstract syntax tree (AST) authoritative covers full language built-in persistence: precompiled headers (PCH)
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PCH / Dictionary
Depend on platform not compiler! No wrappers needed if LLVM-JIT available (e.g. all LCG platforms) Less disk size, less RAM: partial loads on demand FAST lookup: used by clang itself
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ROOT I/O
type names change
ROOT with CINT ROOT with Cling Old TFile Future TFile using namespace std A::B<C> new lookup 1) change type names OR 2) Backport to old ROOT // CINT: vector<string> A::B<C> // clang: std::vector<std::string> A::B<A::C>
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Type Names and ROOT
Very different from CINT7!
CINT7 cling Type Names CINT-compatible Functionally equivalent Reflection DB Reflex clang Type Lookup CINT, Reflex clang Dict Format CINT, Reflex clang* Handling A<B=alloc> vs A CINT vs Reflex clang
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Dictionaries
selection.xml, Linkdef.h will map to same selection algorithm (already implemented) Selection on clang AST (to be done) Backward compatible invocation and
- utput (happy Makefiles)
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Reflex
Becomes 2nd-tier reflection interface Reflex exposes underlying collection types through typedefs. Two options: Copy clang AST to Reflex Change underlying iterator types Up to the experiments to decide
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Status
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Status
Interpreter: ROOT with execution in cling, reflection in CINT Some CINT extensions implemented .x hsimple.C just works! No changes in clang + llvm needed!
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Status (2)
Reflection: Linkdef / selection.xml parser 70%: Reflex dict from clang AST 50%: dictionary in PCH, to do: >1 PCHs, AST node selection 10%: TCint ➠ TCling
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Plans
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Plans
PCH dictionary Independent: validate type name chain header ➠ rootcling dict ➠ Reflex ➠ Cintex ➠ CINT (Reflex because of similarity GCC / clang type names) Verify compatibility of type names in reco file
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Plans (2)
Offer interpreter to clang by summer: visibility, show good manners Embed in ROOT, --enable-cling Implement missing + functionally required (cf. backward compatibility) CINT features Study cling + multi-threading
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Outlook
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Outlook
Long list of crazy items: who would’ve thought a compiler can...! Working down the list until we’re done Now that basics are there: regular cling progress report @ ROOT.cern.ch (search for cling)
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