XDR in Compilers

8/8/2019 XDR in Compilers

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Implementing xDR inIncremental Compilers

By

Mahalingam.P.RSemester 1 - CSIS


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What is xDR?

The term is similar for those who have usedRPC

Stands for External Data Representation Defines a common format for communication

between two machines or even domainswithin the same machine...

One of the best methods to implementplatform independence and overcomehetrogenity...


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Why use xDR?

As discussed in previous sessions,incremental compilers shouldn't go throughthe entire reverse engineering process...

XDR provides some level of stoppage for thisprocess

Instead of implementing a decompiler as such,

limit till the xDR


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Need of the hour...

Incremental compilation is catching up fast There have been such designs as early as

1979!!! And , it was used then in safety-critical

applications like nuclear data acquiringprocessors

Reliability was the keywordReference: IEEE Transactions on Nuclear Science, Vol. NS-26, No. 4, August 1979 An

Incremental Compiler for Data Acquisition L. M. Taff and F. Sporrel


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So, what is the differencenow? But now, the processing has diversified

further... Quite a lot of hetrogeneous applications used

now Integration is the keyword!!!


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How it works...

Generate a xDR for all the source languages Patch up the required places and recompile To remove, just remove that portion of the

xDR

SOUNDS EASY... DOESNT IT???

WELL... IT IS NOT!!!


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Design issues

Tracing the portions to be edited is not as simple asit sounds

The sources are actually merged by the compiler

creating support issues Also, there are quite a lot of combinations taking into

account the number of source languages and targetarchitectures and OS available

Reference: Ambiguity resolution analysis in incremental parsing of natural languageFabrizio Costa, Paolo Frasconi, Vincenzo Lombardo, Patrick Sturt and GiovanniSoda, Department of Information Systems, Universit`a di Firenze. Italy

IEEE TRANSACTIONS ON NEURAL NETWORKS, VOL. 16, NO. 4, JULY 2005


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Earlier suggested solutions

Use of Recursive neural networks for selectiveinterpretation

Problems faced then:

Complicated tree building mechanismsModular design difficult to integrate

RNN somewhat difficult to train, and can stillgenerate errors

Reference: Ambiguity resolution analysis in incremental parsing of natural languageFabrizio Costa, Paolo Frasconi, Vincenzo Lombardo, Patrick Sturt and GiovanniSoda, Department of Information Systems, Universit`a di Firenze. ItalyIEEE TRANSACTIONS ON NEURAL NETWORKS, VOL. 16, NO. 4, JULY 2005


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Some implementations Incremental Hope

Reference: IncH: an Incremental Compiler for a Functional LanguageJames Gil de Lamadrid, Jill Zimmerman


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Code generator sample Incremental Hope

Reference: IncH: an Incremental Compiler for a Functional LanguageJames Gil de Lamadrid, Jill Zimmerman


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A flexible back-end UQ*compilers

Reference: Building a flexible incremental compiler back-end Phil Cook, Jim Welsh,

Ian J. Hayes, University of Queensland, Australia - May 2005


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More on UQ* systems

Reference: Building a flexible incremental compiler back-end Phil Cook, Jim Welsh,

Ian J. Hayes, University of Queensland, Australia - May 2005


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Possible solutions

Use traceable xDRs... We have seen such an xDR and have been using

it quite often - XML

Split the compiler to two parts A compiler to generate the xDR, which is source

language dependent An interpreter to execute the xDR, which is target

architecture and OS dependent


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Final skeleton of operation


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Conclusion

We have seen that incremental compilers arecatching up fast, and diversifying into a varietyof applications

Hetrogenity has to be tackled so that thewhole concept doesn't freeze as such

We are also able to arrive at a wonder xDR

in a daily-used representation - XML


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Applications

Parallel Incremental Compilation

- Like distributed compilation, here, wefragment the whole code to parts and compile

them in parallel

- If co-located, extremely effective

- On a network, the network bandwidth is an

overhead

Reference: Parallel Incremental Compilation Neal M Gaffer, University of Rochester


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So, what next???

Try to implement this concept of xDR withlanguages like XML, which provide universaldata transfer opportunities...

USE OF XML BASED xDR IN

INCREMENTAL COMPILERS


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QUESTIONS???


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THANK YOU...THANK YOU...

XDR in Compilers

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