Compilers and staging transformations

Abstract

AbstracL.Computations can generally be separated into stages, which are distinguish(d fl'nm one aaother by {,iHn,r frequency of executiou or availability of data. Precomtn~hzffo~and)eT~enegred~c~ioninvnlvemovingcnnu)utadon among a co]lectiou of stages so that work is done as early as possib]e (so iess time is required in later steps) and as infrcquent!y as possible (to reduce overall time).We present, by means of examples, several general eransformadon techniques for carrying out precomputation tra.l~sA~rmations. We illustrate the techniques by deriving fragments ef simple compi]ers from interpreters: including an example of I~rotog compilation, but the techniques are applicable in a })road range of circumstances. Our aim is to demcmsvrate how perspicuous accouuts ofprecomputation and frequency reduction can be given for a wide range of applications using a small number of relatively straightiorward techniques.I{elat<ed work in partial evaluation, semantica]ly directed compilation, and compiler optimization is discussed.i, IntroductlonoAm~mg ,~}m multitude of program hnprovemcnt umthods u~cd by programmers (manually) and by compih,rs (automatically), a snm]l nun~bcr of t}lentes seem to predominate. Two of these, usually called keT~c J r~,h~eh'o~ and precomp~taHoz L refer tn classes of optinaizntions for detccth:g eomputations that can be shi[ted, respectively, to tin,texts in which they will be carried ou.t less frequcndy or to contexts in which cfflcicncy is ]ess critical.We refer to there Live techniques as staging frrz~z,@ormaffona. °Autb~rb curre~*~ address: Tech~ical Uni~*'r~ity nf Demuark, bidg. 343, DK-2800 Lynghy, Denmark ~This rest.arch w~k< supported in ]>art by th~ ()i]ice of Navn] R~:s~'arch u~d~.r co~;~ract NO0014-84-1{-0415 and in !The views :111,] conc]usior~s contained in this document are t]Io~e of the a,ldlor:~ m~l should ~of be interpr,.ted as rep~es{'nting tile official policies, Giber expressed or implied, d DARPA or the U.S, Go'¢ernment,Permission Io copy without fee all or part of this ma~eriat is granted provided ~ha~ the copies are not made or distribmcd for direct commercial advamage, ~he ACM copyright no,ice and d-m tide of the publication and its date appear, and no,ice is given that copying is by permissior~ of the Association for Cornpming Machinery. To copy otherwise, or to repuMish, requires a fee and/or specific permission.La this paper we suggest program trm~sformadon tcchniques that can be used to provide explicit and prucise accounts of certain kinds of program improvcnmnfs rdated to these staging opthnizations. A sllrprisingly diwwse eo]h'ction of program structures alld progranlo~];lg t(:(ln/iqlnts ca11 t)e explained in these terms. It is the i)m'pos( , of [his ~,x(,rdse ~o give a hint of this diversity, to demonstrat(, how programs of great complexity can often be <xp]ain<:d in very si.mple terms, and, uttimah,ly, to anticipate a basis for int~,ra<fivt~ mechanical tools.Procompula~i,m aml [rcqmnmy reduction, takt,~ broadly, encompass activitbs rauging f~'om ~ode mnthm opdmiz...

Syntactic Accidents in Program Analysis: On the Impact of the CPS Transformation

“…As a result, "binding-time improvements" have been developed to milk out extra precision from binding-time analyses [16,Chapter 12], to the point that partial-evaluation users are encouraged to write programs in a very specific style [15]. That said, binding-time-improvements are not specific to offline partial evaluation-they are also routine in staging transformations [17] and in the formal specification of programming languages for semantics-directed compiling [22,Section 8.2].…”

Lightweight modular staging

“…The concept of staging goes back at least to Jørring and Scherlis [22], who observed that many computations can naturally be separated into stages distinguished by frequency of execution or availability of information. Staging transformations aim at executing certain pieces of code less often or at a time where performance is less critical.…”

A Generator of Efficient Abstract Machine Implementations and Its Application to Emulator Minimization

“…This usually affects performance negatively, and therefore a refinement step, based on pass separation [6], a form of staging transformations [7], is taken to convert programs written in L A into programs written in L B , a lower-level representation for which faster interpreters can be written in L C . By formalizing adequately the transformation from L A to L B it is possible to do automatically:…”