Communications of the ACM, 26(6)419--429, June 1983.

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

19]Pa ul R Wil.sno ad nThmosa G Moh.re D.sieg nfot e opphrtouintsci argabegcolle tcor. nIA CMSGPILAN 918 Conf9eercneo nO jectb rieOtnde rPgoraminmg ySstms, Langeuaes andg ppAilations (OcPOLS A'8)9 pa,esg 2{33, New O5lrane,sLouis ain,aOc otbre1 89. 92]0Ba ry Hryase U.ins gey obkectj poprotuisn tomco leltc odl bojctse. InA MCSIGP AN L9191Co nerfnee con OjebctOr ented PiorramgmignSy setsm La,nuagge sna Adplicatiposn (OPOSAL 91)',p gesa 3{43,

261]22 2]] 342]2 5

]oFruthIntern atonai Clonfernce en ArchotietucarlS upoptrf roPro gamrmign Lnguagesa ad nOepraitgnS ystmes (SPLOSA VI, pa)eg s69{170,A rpil 199.1 anStaCla ar,CA 26]. aPluR. Wlion. Operstian sygsemt uspprot for msll oajbects .InInt eratinoanlW rokhsp oo nbOejctO irneattionin Opertang iSysetm, Pals oltA, Caoilfrniao,O tobcer19 91.I EEE Pres. seRvsie verdson it oapepari nomCptuin gSsytmes.hoePixn,Arzoina, ctobOer 191.9 AC MPrses H.nry eLeiberma annd CalrH witt. eA ral-eimetg rabae colgectorl bsea dn thoe ifelties of obmjcte. sCommuicnatons io fht AeC,M 2(6)6:4194{29,uJen 9183.W atlreR. Smitha nd oRbrt Ve.W elland. A moedl of arddrseso-rentei dsfowtrea an haddrwaer I. nPoc. 25thrHa aiw iIt'l nConfrenceeo n Sysems tScences, Janiuray 191. Cr9aig haCmbes.r hTe eDsgn iandImp lmeneatito nf ote hELF CSmoiler, apnO pitizmingComp lei rof ran Ojbcte-OreinedtP rogammrin Lgagnuae. PgD thehis, stanfoSd Univrrsity, March e1992 .JonhOu terhostu. Wyha en'r tporatiegn ssteymsg ttinge afstr ae sast fs haradwaer? n UISEIX NSmmeruCo nfreecn, epags 247e25{, 6nAaeih,m Califrnoia June,9109.IEE E Pres. Andrsw e.WAp pel nd aKi aL. iiVrutl meamroyp rimitiesv forus e progrrasm.I n roPeecdngiso fteh

7] 2aPul .RW lsin,o ShubehdunS . uMherkjee and S,eetalhV. Kakkda A.nomaliseand aadpattoin i nth aealynsi snad edvelopemn of tpeprgian pogilies.cJ ounra ol fSsteym asndSo fwtaer,1 99. 2Tecnihcal ommCuincaiont to, appae.r 82] eJna-Lup oaBe anrdGa ry R.Sag r. Denayicm miporemvnt oe flocalty in iviturlam morye sstemys. IEEETr asancitnos n SootfwreaEn ingeeinr, gSE-21(:)5{624,aMrhc 176.929] Vniect Cane andtT omhasGross. C moibing nht ecncopes oftc mpoessior nnd caahcin fogra tw o-leve ll esytesm .I nouFth rItenraniotnla oCnfeerne on Acrchitcteurla uppSro tfor rPgroamimn gLnagauegsand Opeatirgn ysStmse(A SLOP IS),Vp gase 00{2029 S,ntaa lCaar, Califonira,A rip 1991. 3l0]M chaie lBrrowu,s harlCesJ erin, auBtelr amLsopn,and iTmohty Mann. O-niln edtaac opmrsseio ni a nog-lsturctured e sylstm. eI Fifth Intnenratoinla Cnfeorenc en AorchteitcraulSu pprt foorP rgroamingm Lnguages aand Opeatrign Sstemy (sSAPLOS VI,) Setepmber 1992.

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

39 Ala] nDarle, Geai Ml .hawS,andSt nlaeyB .Z ondk,i eitdors .Ipmlmenteign PressteitnObject Base:sPrniiclepsa n Pdractce (Pirceedoing sf toh Foureh IntterntaoialnW okshor pn PersoisenttO becj Systemst.)M rgano Kuamfna,Ma tha'r Visenard,yMas ashcsutts, Sepetmbee r919.

0]4 Pua R. Willos and nhSetel aV K.kaak. doPntei srwzizinlgat p age aufl ttie:mE cinelty na compadtily subpoprtng hug

ie addersss en ostnaardd ahrwarde .nII ternatinoanl orkWsohp onO bejc trienOattio innO eparitn gySsets,m agps e643377{,aPrs, Firane,cS petemeb r1992 IEEE .rPse.s5] J. Eliot . Boss.MWo rkin gwth ibjoecs: tTo siwzzel r noo to tswzzie?l eTcnhialcR pore t90{83, nUversity oi Mfassahcusetts Amh,erst, assMahucetts, sMay199 .06] Se h t. JWith eandDavi Jd. eDwtit A. epfrrmaoce sntdy ufo latrneativ object faeuting lndap oiten rwizzlsing trsteagie. Isn 1th Int8renaitoaln onCerencf oenV eryLar egD taaB ses,a Vacnouerv,riBist Choulmbi, Canaaad Oct,ber o199.2T oappae. r]7 Hnry G.e Bkera,Jr. List rocesspni gi renla imte no aersia lomcpteu. Cormmniuctaiosno f ht eAMC 21(,):4802{924,A pirl 9178. 8]ndAer w.WA pelp, Joh nR E.llis,ndaK i La. Riea-tilm ecnourrentc grbaag eclloeciotno n tosk mcluiptroecsosr.sIn rPceoeings dofS IGPANL 8'8C nfoeenrc en PrograommngiLan uageg esigD nad Impnlmeneation, tpages 11{20 SI.GPAN ACL MrePss, une 198J8 Atl.ata, Georngia.9] PualR W.isonl. niUrocepsos ragbare cglleoctin oethciquen. In snItenrtiaonl aWokrsho opnMemor y Maagnmeet, panegs{41,2St. M lo, Fraacne, eSpteberm19 2.9 SripgernV-rlegaLec tuerNot e si nompCtur Scieece nvlo. 367 10] Je r.y eS .Cahse,Heny Mr L.vy, edEawr D. Ldzawosk, aand Mihe Bcker-aHavery .Lihgwteihgts hrad obeecjt sin a6-4itbope atringsystem .nI CAMSIGP LNA1992 Con efrece nonO bjct Oerientd ePograrmimg Snsytmes,anLuagegs nd aApplicaitnos( OOPLS '92A),anVocvure,B rtish iCluomiab C,aadan,Octo er 19b92. 11 Hans-J]uergneB oeh mnad lanADemer . Garbagseco lletconii an nncoouperatievenviro mentn Soft.arewP ratcci ena dxEprieneec 18,(9):078{820,Speembetr1988 . 2] 1avidDWal lcae.Ru timn etye psuppor it n aCdnC++ Tech.ncal Rieopt rervisoin 1., C1gyns Rupoets, r9129 13.] Chrael samL, Gbodrno andis, JaLc kOenrtsin, aedn an DWierne. The bObjctSteor eadatabes sstyem Com.muicntaons io thef AM, 3C(140:)0{56, 3ctOoebr1 91. 194] Rciahdr rGeeblant. tUpunbishedl echtncila eportr not e Mhbyoad dres spscae .ecThnicla rporte,isLpM chinase, Incoporaretd 15.]M. nAdreson, R D..P so,e nd C.aS .Wllaca.e Ap sasorw-dcaapblityi sstem.yC opumer Jourtaln, 92(1),1 968.16] ose JlAesv arques Mad nPuloa ueGesd .xtEendng the oiperaitgn sstym toesup prt oa nboject-oierntde evinronmnte. I nAMCS GILPA 1N998C ofnereneco Objenct rOenied troPgraming mysStms, eLngaague sand ppAlcaiitons(O POSL A'98,)pag se1 3{1122,Ne Orlweans,Lo uiisana Oc,obetr 189.9 1]7 eMndl Reoesblnuman d Jhon K.Oust ehort.u Th deeign asdn milepmenatton iof aolg-trsctuurd eel ystesm .nITh rtieneth AMCS ypmsoiumon pOertina gysteSms rinPcipels p,aegs1{5, 1acPi c roveG, aCifolrina,Oc toebr1 919 1.] 8Jcquas eCoen. hGrbagae cllectionoof l nked ditaas tucrturse .ompuCtign urvSesy,1(33:)41336{, 7Spetmebre 981.1 18perfor

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

macn betweee nnormal( on-nocmrepses) RAdMan didsk26]24 W.e ra eevedloipgna adpivte omcpersion stcheinqesut aht exlopti ht eypicatl owl inorfatmion cntentoa n dwro-diws aligneemtn ofh aep dta aldse,ndat eh tsrngoal ignenmta d nroguipn regulga

riiest mpiseo dy btpiyacl hep aalolacion tscemehs. I nou rniiiatl tets,s w ehaevgo ttn ecopmessroi nfctora sfor C++hae dpta taha tavry bteewn e3 an0d 90 erpcen with tastfs inle-gass algorithmp, wshic cha nocprmsse a4 KB p gae n ai vey rfew illimsconed osn a erlatveil sylo (wun SPASC REC)L rocpsesro W.ea re potmistiict ath orft piyac lprogarsm we ill wahceivecomp rseison fctora ofs wtot o foru, ith wcomrpessoi ntkaigna frac toni foa ilmilscond onenex -tenegartio nrpcesoossr T.xesapro idesv epsistenrec wtihgo do erpfroanmc fer oC++program rsnnung ion tsoc hardkwaeran dstckoop eratng isstemys.It is s rpursiiglyns impe lna edxblie,hwover,ean d eruqireslittl eo ro cnanhg to exestini compgleis.r hTecur ret nervsoni f our operistsne sttro, excelding thu loe-structugre sdtrago eodmlue, i lses shtnaf or thousanud lnei so Cf++cod e. Lg-otrustcreudsto rgea das dlse tsah two ntouhasnd lnie.sW hlei w eexpct theee sugerst ogro wso emhwta a,d ne expwect o tad dmor meoulds (eeg.. f,roc ocunrencyr cotrnl)o,thi iss gaariftyingylsm al lmaunotof co defo a presistertnst raoe gemhancim swit hhghip-eforranmecadd rsse rantsatlin aodnc hcepoinktni.gThi ss mipiclty andie ibxiilty sil agrey due lto te use ho foipternsw izzlig an pagt eaulftt ime whic,h lest u tseatra ddres trasnlsaitno, cahcng,ia dn ecoveryra sn arle orthyoogan lfaetresu .dAdesrstr nsaaliontc n aebp rformed byea ccssepr toceton tiap rhadlnre,s ithw acon vneitonl avrtual mimeor peyrfromnig atdac achng. iWite rprteotcoin ahnderlss upopt rlgogin griwtes t oa modularl o-gtsurcutre dtsorgae ubsystsm.eP ae gfalu-titme adrdes srtnasatlon iah sssenteially eroz ovehred aorfpr oragms ithw oog dolcalti, ayd npapeas rtob competiteve wiith oter hschemsei gnneral. eLkeiwie, pagsweie soglgignperf omsrve y rwellwhe wrnte iolalctiy isgood, ad nsbu-apg eloginggp romisse t oeepk ti ompetitivec henwwr ie ltcoliaty si oorp .uOr omdualr apropcha papare st woorkwel, lallwoig nu st oasily echnge starageom aanegenm tcshmees .Txaseand its olg-trustcurd setrogeasy temsar proemsingi oth ab sn easyat-ou-es,igh-phrefroanmcep erisstenec emchansim nda asa xieble etsbedt orf asbcires aerchin olclaiyt,idtrisubet dsystes, anmds otage trchenqiesu We. ouwd lile tokt hnka th organizeersa d panrtcipinat osf PO-V,Sas elwl s seaeval remisarnst udent swh oelhpe ddesgn TeixsaR|oebtor Bayador,tif CAhauryd, Shnkar Krasinahoortmyh,Rajiv Kuam andrRe hk aiSngah.l Thans klas to oSethW iteh, fr shoarngit eh bnecharmkcode fro m6;]to Ma k rohnJtsoe,n or lasf-mtnuitep rogramimngh el piwh thtel o-stgrutcred storugeas yste;mand to J nateSw siehrf r help oithw ht gerue sadn extt.9Con lcusinsoAkcnwoelgdmeenstReefrenesc] M.P.1A kitsnno P.,. JBialye,K .. ChJishol, Pm.W .Co cshkot,t ndaR . Morirsno An. aprpaco thop esisrtet npogrraminmg T.heCo pmture oJunalr,26( 4):6303{6,5D eembce 19r83.2] .WC ckohstot M.,Atki nso, Kn C.ihsohm,lP . aBliye and,R Morr.iso. Pnrsietest nbjectom nageamnetsy stm. eSftowrae rPctaie cna Edpexreicne,4(1)1:4{79,1Janu ayr19 8.442A s imilarappro ch haas een tabek nfo cropmessirng omcilpde oce din he Acortn ystes, tmoughh t ioeratesp on arograpmiws ebsais rtaerh htna paagwiseeb ass.i17

o

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

thre vaEirnastconsist ntly eotuerpofrem odu syrsetm, gain ab y amasllm argn;i all f ohest syetesms uotepformred bjOceStoter. Agian,we m ut sstess trahtth es areevery p rlemiinry raesutls,nadt e shytemss ae rnt oxeactly cmoaparlbe.(In particluar,O jbctSeore it a cosmermiac lprduoctwith mayn avandec deafurest ra,htret ahna tsirppded-on wmiimalns styem ileko ru.)sQ aultaiitelyv,touhh,gou rsyste mappaers toperf orm etrexeml yewl ln termi sof addesrst rnaslatin cooss 4t an]dto ebc opmeitivet wth itoher ystses mn tierms fo hcekcopniitgn. n the neIa rtrme,ou r mia gonlasar e otco pmelet the ype tdescrpitr ogeneraotr nadlo g-tructuser dtsoraegm cehansms is ohat wt can eettsa d bnechnamrk exTs maoerfu lyl .Atfe ar perodiof debggung aid ntnuig,n wewil lthe isnuse batae rleese, parboblayear l yni19 3.9 fAtreTexas i stsabel,wei tenn td oreelas ei tgenerlayl s afere sftwoae, mosrtl ikey ln ithe pubilc dmaoni S.oo nthreafter,e w entindet ocreat ea lceni-servertve risono fTex as f,rod itribsute adppiclatino. (sW may aesl otr y diastrbiteu vdrtiaul emmor ayppoarh.)c eW are xpleoinr sevgrale ssuei selartde to distriubet systdmes,in cldiung haivn gndipeedennlt syahable rand ropettcbla heaepa erasw thii ans igln setoer. W ere cuarrntelylea nnigto wrdaa sc ehe mhtt is asiimlr tao het ropteciotn dmoia snhceme fot ehOp laoper aint gyssetm 1].22 A ma0or gojl afoth sip ojerc ti tso rpducoea useful hi,hgpe-rformance perisstnet stor ean givd eita wy, soa htatwe c nad veloe p sigan cinta uers abe of actsau lrpgormsath a twlil ulfy lxploei thetpo tnteilaof uo prioner twiszlizg andn stoareg cshmee.s Orude csiio nto sppurto++ Caws lrgealym oitatve bydthe d seriet oh aev a isngi cnt namuebrof pplacaition stathco lu bdeeas iylport ed t ourosy ste, mo thsta ew an cpoperlry evlaute ai. tOnc wee ahv a useer asbe, ew lsa inotend otu e seTas xa as ehivclefo r bsaic rseeachrin loc altyiof re frenceein lar g eetssof d ta.a Conevtninola lsesteymtr aecsare di ultc t inteorrpet,b eausc teh reefrenece sotle b lock sra e aevyrcompl xefunc toi no fropgam'sr cnocpeuat rlferenecign ebhvaor;ido ami-nelvle boejctsm y maoe frvom l belok tc lo blocke p,ehrpas bieng n miutiple llapcs ae otce, andnun realtedobjec ts my maapt o htes ae logicmalo rp hsiycalle lockb oev ritem.Be casue aper istestnstor e repserevsob jet cidneitty r,feernee becahiovrs holudb esom ewht aasier toe nitrepre tnd exalopit. Afertg athrengir feeercn tercaesa d rnunnni ghem tthruoh sgimulaotr sw haeev deelvoed 2p7, w]eintend t oexperimen tithw ctual amipelentamtionsof novel eprlceaenmtpo licei, snda repetchfig pnlicoes eixpoliitn adaptiveg eorrgaizntian.o daAtipe verlpcaemnt ewli lrquerei siugn a nextrneal paegrm echnaims (o rsoetmhigns milir)a to ovrried etehd efult aacchig nf the undoerlyin girvual tmeormy. Adpaitve r

eograinatzion or frefetpcihn 2g8 2,] can6 tsargihfotrawdlr ybea ded todth eogl-strctuurd setore, ue dt otsi wrtie-aynhwer eplioiec; sthi swil allos rquiere na exetnar plagref aclity it oxploietit ofrt hel oaclc chinag mcheains.mL o-gstucrtuer stdoagr alseo lnde itsesflto comp rsseeds oragte of daa tbolkcs .iGevn hat tlbcok scn amveoa orun dno tehdi ks anywya,i t si as mlla stp to eet lthe mvayr n sizei,dpeedningon hw woell tehyha pepnto ocprmsse23 .rPevious wrko n cimopesres dl etorasge hasf oused pcrmariily nircesian geect iv edik capsaciyt orfty pial cle dtaa.T hey hertforee fcus on botyestri ng-riontee comdresspin tochnieuesq suchas ybteiwse eLmep-Zil varivatn 29,s 30].O rugo lsa rea uqie ti dreetn. e aWr feoucisgnon dec raesig en ctieve emmory alentcy fo tryipac lheap dtaa.G ievn tathw epa ge boejtsci an haep fomrt, andaa solst or themein a nonl ylishglytd erintefor atmi nteh epristsne ttors,ewe ar em uc hmreo inertsetde n ihap deta laayots uhtna covnnetinal ole/I fOomats.rW ewou dl ike tl aodd aelve lof ocmrpssee indme-mor sytrago eotth e emomy rhirercay,hi nermetidat ein22Ou r subhaps eouwld tkeat h place ofe thei rlw-oevel loniton f conoigtuou ss\egmntse,"an dsbheuaps imgh atc ts seat osfo jbctes iwh dtstiinc tpoliciseco tnorling ligmratoi, rnepilaction c,oehrecne a,d garnbge aolceclion. 2t3T hisis apticrulral yaesy ficop yin gompcactoniis sud te orelcima ol spgce, becaasue contguiuos alocaltoni rgionesma k it easy to aellcaote arivaleb-izse bdlcoskc otngiuoulys I.'tsn tomu ch hrader for annomov-inglo gr esue plocy, hiowvere,becaseudata bl cksodo 'tn end etob e soret endtrile ycnotguiusoy; thil grsatle siymlpi se ackpng piobrlms.e8Fu tru eorW

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

muh chcepae,r and papicalionst myae ploixtt ht aybc heckpintoingmo r eferuqnelyt.In th a tcaes, te timehspe n dti gnpa egsmay o gups gniic nalt,y na dneg-ainre dirtdybi tsche em swill ecombe ocrerspondngiyl orme tatactriv.2e0Beside ths etmiec ots f oapge i ngd,htreei sasp ce acsot,anmly theeco t sf keoepng cileanv rsieno sf oodimed agesp Fo.rsho trtra sancitno, shwee rcehkcpoitinn gwitersa erthe liimitn gafcort, hts iisn ot gnerelal y arpoblemt|h eporlem bist hetim e reuqried o comtmtia m derota nemuber fo driy tpaesg t oidk, nsto htes ortge areuiqred orf a arle gnubem orfd itr pyags. eFr olngore rantastioncs,n ohetot erhh nad t,eh hseer ovumle fod itr pagys emya eb a sgin cantisp ce coast.W hevae hosenc o ltmii tthsico t bs kyepeniga rel tiavel smylla ub r eofv esiron so fdirtypa ge,sa n wditirngout pa ge searyli fhte u erb lls .Th ebuer isma naged inroughl yelst-aerectny-clhaneg dfsaion, hso hatt he mostts atblev reioss anr wertien rtst W.en a chahnedgp ge versaoi in sriwttn erfm toh beuer, thecor ersopnind page igsacc essp roetced ts toah tsbsueuqnetc anhgs ecnabe dteecetd, ad nane wcoy mapde.W e elbeve ihat ttihs tsraetgywill e good bfo the perrormface nfob ot longh nd ahors trtnasctiaon.sWr tiig oun chatneg spreatumrly eam yicrease dins bankwidth deqriur

emnte sfr longo trasnctianos, bu it siklelyt oicnreae osvraellpe frromace bny decraeing scommitlat ecnyb|lcoksth at aer writte npreaturelm yan(d whihcd notoc hnga egaain efbreo thetra nasticn ocmomti)sneed ot nbe rwtiento t uocmitmti me. Gvine som eloality oc wrifet,s his stohld uncriesa tetol arta c smoehwat, ut bmaek t lissebu rst.yC rrentuy, lTexa'sl g-otructuredsst orag ecshmee is stll under idevlopemnt,ebu tav rsion eof Txeasis upa d runnnngiu isg a nsmilep riwet-aead lohggng ishece. As remporte id 4], ntheswizz lngi chsme perfeomr sase pxcete: dor fporgarsm ith woodgl coaltiy,th ecst ois sseenitlla zero,y wihe florp rgoamsr ithw opor locaityl, pgang ciotssdomi ane tdadrse straslantinoc sts.oOur yte pesdrictop rsstyem erqiuesr som henda-cdion.gT his s due itobug is nte GhU CN++com pleir, atrhr etanha ny prboelm iwt hTexas tiself we;hoe andpex pce that thtsee ubgs wlil be exd oosn.W eaera los dveeolping uro rppeocesrsr oo takmet e syhste mocpmile-inredepnedtn .Teh reprpocsseo currentlr yarpss C++e an dreocngize scals se dntiion, bstut ehact alu gneertion afo urtinmedesc irptor sis not ocmletep C.echkopntingi prformanec, eevne wthoitu htelo -sgtucturer le sydsem tadns u-bage poggiln,gi asccepablet P.reilmnaiyrb ncehamrk sfo rshotrt rnsacaiont, usisn cogde fomr Wihte nadD eiWt'stvar int aoft eh O1 Obncemarkh,hsw perofroamnec t ob eocpmaabrel t the sostyem stey hmesurad,eo nc opamabrl eahdwarer .Exctaco mpairsos nra neot osspilbeb ecuae sf odi eerncesin hardare cwno guatrins.o12 Wthia ve yr prlemiiarynversion of the lg-soruttcrued store,p erfrmoace nappaesrt ob eigsi ncatly benttr,ea ndi nact fuor ystsem upesrc illa oyuterforpm moss to tfehs stemsyreport edin]6 These. esulrs aterh ard toi netpret,rhow ever,otb hebacsueo thef iexnact mtca hn ihraware dueds,a n bdeause ocr uystems sia isnglewo-krsttioans stye, mwhielth seysemtst stede in] w6ee rtwo-woksrttaon cilietns-erverco n uragtoni.sIn aditiodn ou, rtsorgea ssyte msii conmlpeet (epseically i tnemr of isst lorgecamltionaa n dcompcaiont trsatgies), soeit sev etnalu peroframnce ay bem somwheta di eren. Ot nteho her htnda, weex pceto rupa e gding tec hiqneu to sedurecc sto fsrtueh, sorw e ra euqie tpelseda iwth uo rreplimniar ryeulsts. n a tesI cotresropndnigt ohiWt ane DeWdtt'is igFreu 7, uo srsytm eouterfopmre all df ohetir Eavirnta sna OdjbetcStoer v(esron i.1)2 yb t leasa a stalm malgin. rn I testa orcrspoenidng t toehi Friureg8,w tihner g-ranid eranstcatons, Tiexs canosistneltyou pertofmre dtow E vriaatsnby samal lmarin,gw ihlet w2o0 e Wblieee thva ten-gairnd haerwdra diertybi s tre aa goo idea dn geiernla 26,]bu t d ono twntat o ependd no tehm a prteest fno rersoan of simpsilicy atdnpo rtailbtiy.2 1L ik Wheieta d nDwetit,e aweru sng iPSRACsattoin ELC',s bu twih ti drenet dik drisve; swe odn' btleieev ht de eierne cn irivde swuold ame k aajom direr enceto preofrmnca,e ubt ew cn'tab certaen.

6.2 Liiimtni ghe Sptca Cesosto f D in

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51

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

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ementign ubsp-ge aolggign so, htt aw ecan ceckphointare asof me moryth ta rea smllaertha n pagse Ra.hterthan w irtignout en tie rdrit ypges, wae acn fotne rwti eot uoln yhotse aptsro afp aeg tat have hcautlayl hcagnde I. nodrr to doeth i,sw neee the abdiilt toyd tecetwh ihcs u-bapeg nuit save chhanegd adn hiwhch aevno t .eW reai nvseigatint tgw possoibl epapoaches rot histn eg-rined ahccekpintiong .nOe i to kseep irtd bitys orfs allma ears,ei hte nre-rainge dhrdaarw eidtr byit (sas n tie hAMR 60 022], )ro crad mrkiag ntcheniueqs, hiwh maicnatni ditrybi s tn iosftarw 19, 2e]3 Ano.hter s to uies apeg id gn i(.e.,wodrby-w-rd coomarpions itw ah ceanlc op) ty nd outow ihh caprt sofd irtypage s have ctaaluyl hacged. Anllo fthee apsproaceh sra iendeenpdnteof ur pogeaiws eoinpet-swrzzliings hemc, aen edpxoiltt h erothgooalityno fa drdess rantsatilona n ddat satorage;heccpoknitngi i scarried uo ta a dt iernet ersoltion tuhnaadd res trasnsatioln.Curr ntely we, nient dt use pageod ig, not nn-ergined aahrware dirdytbi st r (sooftwra)ecard m arkngi bec,ase uti eruiqrsen cohanegto t heha drarwe,opertaign sysetm, o rcopmlire, na we bedlevi eitwill pe frrmoqu tiew ell,giv n ecurretn atros ibetewn CPUe and isd spkeesd Page. idng i s lsa conceotuallpys targihtfrwaro|itdis ony nelescsay to reepka leacnvers oinof e achm od id peag, anedcom par etehm oi ddea ndu mnod ed iapgesat ceckhpoit ntmi.e nlOyt ehcha nedg aptsrn eedt obe writtnet othe log .We a r ecrrentluy iplemenmtin paggedi n using wgrietpro-ectiotn ratsp o ttrggeir a cpyo ponut he rtswr ite to ecahpag e t;eh wrteipr teoctino taprh adlen rcoies tph epga intoe acl an veeriosn u ebr,nuprotcte tshe oirgnal,i nd aelst tehp orramgr esme.uThis sc hme ienurs ccstos poportioraln o tte hnmubero f drtiie dpagse ep trarsnation|cach ewitren ptga ceaseus atra, pap gae coyp,an adp gead i g noprateoni.In a ditdio, tnhreei s saacpe ost ofco e nage pfo lcean vesrion epr ape wrgiten. Ittm y saem teaththese csts oraequi et hig|anhis lotad wrete tioa 4 KB pa g, efr oeaxmle,pwill c so sevetar ltohsuadnins tructoin st caeckpoiht nime.tWe ebielevt hi cosst siq uie acctpetale bfort he ajomriyto fa plicptians.o Themai n ost oc fchekcpintino gsamll tanrsctionasi s ont het ostco fexectuig instnuctiorsn ni meorm,yb t theuc sot fo isdkopera tino st coomim tata do ntonolvtaie stlorage.It si tarattivc toee pxne thousadnds ofin strcuiotsn t avoodi rwiitn agne tnirepage o data.f oCnsder i atpyiac hlgih-peforrmnac werksoatton disk witi ahba ndiwdh otf rouhgl 4yMB/se focrlar e grwiets, e..g,str aeimgnda t at a oocnitugou arseaw ti hew sfeks. eoFu rmgebyate pesr escodn i 4s BKper m illsecoin|or roudglhy apa ge perm liliseond. Oc tnh etheroha nd cons,iedrCP U operatonis .Cmomn owoksrattoi and nCPsp eesd re ainthe ets ofnM IS,P soo tonb en tihe hunderds.A 10 0 IMSPp rceosso rcnae ecutex1 0,0000i ntsrctuonsi ep rimllsicenod. t wiIll threfereo ebw otrhwhle to spendi oughry 10l0000,insrtcuitons t sove aonepag es 'wrothof

datawri te.s (eBcuas epgaec oypng iad ndi nga r meeomyrin-etsniev,th er siepde my natos clea irecdlt yiwh ptorescor spseesd. heTy haevexc elenl seqtuneitlal oalctyi, hweovre; hteyare lielkyto e xplit inocrease isnmemory anbdwidth qiut ewlle,rtaeh trhan ebnigc osell tyedi to emomy lartecn. Iyt hosluda lo sbe otnd ehattthe d ingof agepsc n ab deoe nn aip pilined feshaoni, ni paralellw ithth ewri tes If .rtnasctaoin commitsar e ht elmiiitngperf romncaefa tcor mo,t pase di gg can nb edone int heid l tiem weilheo terhpag se reabe ign wirtent Th.e catul pagea d ig in tshreefor leiely kotb e eecitevy lfre, etouhhg ht terappni angdc pyiongi nost).Curr ne operatitg nysstem ipmemlntetaino snciurhi h trgap veohears,du ualsylar oudn10 00,0 o 2r00,00i sntuctroin cylce psre rtap .vEe sno, thi ss inly o fraaciotn o thef insruttioncsn eecsasr yto neagt the aedantvgea ofp ae dg ni.g Ita peapr sthtap ga edin gw ll ileiimnta mest ofo het csotof w rots-asce wrti lecaolty. Impirveodt rp ahadnlig pernfomrnace wold uatunallyrincr ase ehe ttatarticenesv so thisf schmee. We(be ievl ehatttr ap anhdlin goerhvades area menale tb sioni cgatn edrctiousn,ad thntao praeitng ysstem mipleemntro sar likeey ltoac ihee thvsoer edcuiton sa sorm epapicationl seploxitv irual temorm yfaicilite; sese24, 25, 2 6] of rmroed eaitledd siucsions so fhets esiues.s) Aacvea tsi nior de rereh:hettrad -eos niolvev dar veey sersntivieto c anhgs in ePC aUd snoratge tehcnlogioe. sf, fIro exmape,lno vnloaile tAMR s uisde fo checkrpinotni,gc hckepoinitg nrwite may bsecoe 1m4

.16 PgaeDi gn

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

the LS Skeespt ishb imtp coasnstenit wit theh checkopntiig of dant lae. Cusrenrty,l w use ae vey srmipl biemtap csannin tegchnqui et no mdsolytf-ere aresa f oidks or wrfiintgn e vwrseoin sof blcosk .This i srthar deier et nrfm oth coeyipgncom aptiocn epmlyodeb y ht SeripteLF S1].7O r uecthniqu eismo re ain tko te hwesepphas oe marf-sweke copllcteoni,an dwebe ielv it mey ae mobera prpopiate thar ncoyipn comgpctian unodr eost mcicrusmatcesn. We(c rrentlu hyaevno copacmto ra atl,l hotugh w iented nto mpiemelnt ne ofo rstiutaois in nhiwh cfragmentaton ciots asr high.) et Is iitenertsni go ntoe ttaththe garba ged eetcitno porlbm esi ritvalliys loevdu sing rfereenec ocutnig, ann dtihs igves terenmodsuex ibiliyti thench oice o fgarabeg eclarmaitno na readlloatico ntsatrgies. eRoesblnmu nad Outsrheuo tsu eat ehnique thac ti sanloaguo ts oengrateinol aopycni cogleltcon 17]i|hattis, hty eatk edvantagaeo fht facet tht mastobl cok vesiorsnl ie ovnyla hsot wrileh,bcauees teyhar espurseeeddb sybuequsen writes tf ote hame lsgocai bloclk T.ey hues aocypnig comaptorc o rteclia mhe tpscaef or osboelt everisnoso lfogica blolkc. Whsle ite geherntioaal heuristinc sili kley o tebe ctive ien osmtc icurmtsnaesc i,t isu nenecssraily inirdcte ad iln-linofrme. Tdhe ifonmatironp rvoiedd b thyere efrneec ocnutign agbrag eedtetoc car easniy lifonm mrre opportuointisc tsraegties w,ihc hate akvdnataeg of ocpmetel inorfm

atin aoobut hichw lbcos krea rfee.7 1Thisop ortunism cpa nvaodi epexdnni e gortwh eerit i snnueecssar,y andmi ht ge bseudt od namyiclal choosyeb etwee namk-sweeprst leyr uese nd copyang coimpacion.t Mak-srwep ie asvadntgeouas whnefr gamntetaoini sanutarll lyo,w a wes xeect it tp obei n ost casem,s ude o ltoclitay e ctes. oResnlumband Osteurhuto avh eeporterd17] tat hamy modenartesi-zedare s af odik1s8con tinan lioevbl ock vrseionsa t all b ythe tiem teihr oclector l\clanes ("opcy ollcecs) tthe.mIn tho esc aess,no pecsial eor tsohuld b reqeiued ro ndtlo n guns rofc notguous oir enrly-aonciguout dssi skapec. uO rbitma pwsepeni tgehncqiueshou l wodrk ell iwnsu c hsitauiton. soCpiygn compaction ah sth adveantae go felmiinaitgn fagremnttain,o ubtincu r sddiatoian,l esslp rdiecablte octss ni pdating yuunoge rbolcskho lind poigtenrst ore lcotad blecks.oI thenw orst csa,e i tpapaesr ot rquere cilaniengal selgents mouygnr then thaeo desltse mgnteb enig celaedn because,cr aeting ew nevsrinso fo inedingx bolcs kaymit esf cluas erfagmetntiona.9 1Pgeaiwse opnter siwizzlingi asttrctavi becaeues tic na xpelot ipsatila lcalityo, bu tapgwise eoperatoni lsaohas di sdvaatagnse, arptiulcalr yn ihcecpkinoint ghort sratsnctiaon. sI trfnsaatcoin sahe vpoorlo acltyiof wrties,p gawieesche ckpionint gwill sva teo mocuhu ncahngde atda a;sngielwr te tioa pag eduringa trnasctainow ill case tuhee tnrie ape tgob ewri tetnto di s.kFo lonrgrun-ingn rtanscaionstwh ih mcainulptae cosinedarble qunaitits oefdat a,this osc it prsboblya nto uanccpteblae s;ipmlyrea dig lnrae gaomnut of dsta reauqresid ikss eek wsichh rea uuslal myor eexpnsive etha tne holgwrite s F.ro mall sratnacsiotsn,owheev,rth woerkingse tf ohe prtgorma si liekl toy erids ie nemmor,y ndat helog witersm a ywellbe t ehl imtini gepfrrmoanecf catro.In t his acs,e te achtul almiiattion s likeilyt o eb disk abdwintdh r(taerh hta nlaetcy), nisnec lo gwirets canb erwittn ae ascont niuos suteamr with ewf eesk.sW ihet ad neDWitt ave hcmpoared ObectSjtore( a agpeiwe scshme esiimalr o tour)s ad nsevealrv ersoinso fth Eesy stm, esungi ne-grairne do(bejtciws)e wiszlinzg an dchekcoinpitgn 6. T]ehirresults appear to ebrao tu thet hsie stat hagpeiws eshceems owk rbste of lorgn tranactionss|ecbuaest ey cha nypictalyl xpeoli stapital ocllatiybu|te xhbiitp oore reprofmrace nwehn tarnastcino arses hor tnad lcaloiyt of rwtesi is opo. rWilhe uorsy set imsd eisgnd eprimrily aof rpalpcatiion wist rhleatveil yolngt rnascaitno,ssuch a tsypcai lCADa ppliatcinos, we ouldwlik eto rovpidesu pportf ro msll transaaticnos as wlel.T doo hits w, eare7 1hTs iisan loaogs tuoopport niustci agrabeg olcletiocn fro energal-puposresy tsms,e as i n91 an] edpseiacll yose mroposapsl b yaBry Hrays 20e]. 18I e.,. s\gemetsn"the| unistof cont iuogsu allocatoin ni teih srsyetm. 9 T1hs icroresopdn ts ohet yticpalap procahemp lyode i ngnerateonail garabeg cloelctors,here wsme goneretaio ni cshseonfor g raabg eclolcetin,oa d alln yuognerge

neartonis ra aleso oclelted cdurng thit coallceiotn 1, 9]2. hiT is snunecessry waiht a nn-oomivg conllceto rweherl ivenes iss nkonw eborfhand.e6 Sb-puaegL ggoin tg Reouce ChedkcpontingiWr ties13

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

igue 5: Rrghti-sahllo lw eidexinngtr ese pyhscia bllco vekrsoi ntha is ptar to afny vlid al evesiron14.I no ru LSS,t e hteres aerr ihgtshall o, wemniag nthat icnoplemt reighmost tsubrtees of het hwloe tre heagn idecrtl o oyft eh otp-leve lndiexin gnoe d(se Fegurei5 ) When . asutreeb lsl ecbuae osfle\ appned,"st hef lu slbtree isup suhd deon anw dt othele t tfob ceoe am irhtmgstosu brteeo fa lar eg srbturee1. T5h aedvanategof th iss tucture rs itahttr ees aerve yrbu hsy, ecabsueo nly th reihtmgostsubt ees are erer invocpmetle,a n dth eret es a awhle io nsvee rorm teah nnoenod edee ep rtah anper fetlycsy memtriclat ee. Thri minsimzei tshe nmuerb o facentsr onods ehat tumts bewr tten wiehn daat alboc ksiwri ten, atn appdeds anreespe ciallyc eahp .Fro smal-lto me iumds-iedz lse,only o en ort owan cestrs oumstb weittern fo ran yrite wo atna birtarrli chyoen blocsk M.sot appnd epoearions tnloyre uire qmdofiinyg hett p-loeelv ndiexngino d,e becusaethe rig htomst evsrae datl blocas kang dhirectly oof i .16tTh is tructsre iu stherfoer eqealuly uistaleb orfr andom saerhca ndupda tepat trens,an da sl foro seria llec nstoucrtion, .eg.,wrtiigneven tlgo. Lsogr clemataoi nina lo-gsturctreuds otrge asstyme 7]1 s esisntiella a yamterto gfarabegco lectlion 81 9,.]C momittnig anw evesrin of ao e dilsonncctes ht teopl-eve lniexdngin deof om tre chrrunet tsateof the el ystse; im ti sterhfeoe grrbaga es(ubejt tocr ecamltiano). Anyl oerwlevel i-dnxengi an ddta ablcos that areknot r aceahlbe rofma alvi top-ldvel nedoeare lik eise gwraabg endamay b er claimede O.ru ol gerlamcatino csehe msiq uitest raihgtfrwaor, derlyignon r ferenec eounctngiof d ta aad nindexni bglocs.k As epcaille (istelfstor ed in teh LS) hSolsd abitm p afo refeb ockls. hTe ormnal cehcpkintong ifoThis requris eoly n asilhg tomi cadiotn t toe rehfeernec-ocuntignschem eus e tdo keept ack orff ered ik slbckos Th.s isi uiqe dt ereint fro conmvneitnoa UNlIXl e trusctruse wh,ihcar elef-stahlowlan ddo nto rquire reeablaningcas het gryowl rgera. 16 Occasonaily, lustbeers muts e pusbhe dowd,nb utt ih serabanclngiis nirfqeentuan thd eomre xepenivs erbaelacings anr eetxemrey infleruenq.t1415

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

I onhte arplipctioan, is might be trpferablee o patged reictly frmo teh pesirstnte tsre. Tohi wsolu dvaid reoundadn storagt ef paoge si nobhtth persiesentt sotrage l aend th eocal lackbnigd ski'ss apw aer. at woIld auls oerude cte pohsisblity oi diftr payegsbei n gpgae doutto swpadi sk on,ylto b es usbquentel pyaedg bakc i nos hta tthye ac nebw irttneto the perissten sttor.1e1N turaally e,vcitni gpage dsiertcl bacy ktot h eeprsstient tsreow uol de besepially cappropratief ro isdkelssc ielnst. eTxs caolduea sliy be omi ed todev cti apeg back tsoth epreistest nstro,e gveinc otnorlove rpgeaout.sThi s oulcd b aceievhde suign somthieng ile kMca'hse xernal tapgr feaciity, lub tit owlud make thes ytsm eomewhast omerc oplmexa d lenss poratbel.Wh ne siungth ev rtuia mlmoreysy tsem fro cchiagn,it s impiortant o atovd icacihg tnh eperssitet snotrge ae lin the lsestyemcac he; once paag eah bese loande fdor tmeh ersiptents tosrge ael into hetv irtaul emorm, yiti imspilitlcycac hd. eCchaigni it anl esyset mbue isra w asteof r soureec, sso teh epsirsenttst orae leg sohld ue stobredin a nu ncahced raeao fd sk.iL ki eanyuseful p resitsnte sote,r exTa susppotrsc hekcoinpint and rgcoever;ywi h t peasritensts otr,et h cenveotinnoalhea/pl edis itntico is lnso,t adnex licpit heckpoictnni mgst tauekt he pacl oef

\sainvg hcagnesto ae."l e hWav imelpemetedn wotdi e rntecheck pointng sihemcesfor Texas Th. esr twasa c nvonteioalnwr itea-ehd aoglgnig chesme; hat its,c hagedn pgea weresw rittne\o t otehsid"e in a log .Th(ep ressteit nsoragtel e iselftwa son ly moid e daftera llc ahnesg wre sefealy writentt thoel go, osth taa rcsah wuoldn t oealvet he toresi nan nioncissettn taset12.) We ahver ecnetly erpalcedthis iwh t moaere xile logb-tsurcture stordgea odmule. athRe tharn reni gno u rcrued rwtei-aheadl oggig nchesm, ewec ose th orelape cboh tthel go an tde herpistset nstorga leewit h a lo-stgurtucreds torae sygsem thiwh scuporpt shccepokitnni direcgtly and eceinlt. Tyh eLSS s esienstilly thea lweor elvles of al gos rtucutrd ee lystsem 7]1; ad mnaniulpats e siaglne argleunca hce del (urrentlcy, arwa UIXNd sikpa triiont) .nI a lgos-trctuuer stored the ent,ri dies is ukeds a sa ol, agn tdh eolg tisel facts sa hetn alrepos toryiof data agpes. aRhter htan\pudting"a lbcosk htt reaidse inxe dlcations oo ndiks,log ial bcoclks an micgart, ewtihn o hom\"e ocatilon .hT\currenet"vreisn oo afb lco iks implys ht ealt sno weitrte nto the olg,a n cdhages ton al e canbe ommicttdeby pdutaig indnexni infgrmaotonit o oipnt ot hte new ervsios nf ohacneg blodksc .Ths\wirte aiynwheer"prporty hasema n advayntags efr oipmleenmitng avdnaedcf ncuionatlity .I hta bsenep romoedtas maaens foinc rasenige ec itvewri et abnwddth (ibya llwingow itrse top roeed necral cynotniouslu yota onctiugou aser of daik) 1s7, but]w eebilee v wallei-mlepemnetd ocvenntiona llgoging cseme can phrefom rismlirla.y31 Froo r uuprosesp, ht erea ldaanvtgase fo\riwet anwheyr" diesk mnagamenetl ie eslewehr. Weihel e wreain treseted in ihg wrihteb ndwaidh,t we ae equarll iytnreesedt i inmrovpingr ade altnecyand anbwdidh, etpescalil foy rroprags thmatma niupatelve y rlagre aomnutso dfaa tand wohe pesfrroanmce may no teb omindatdeby hecckpoitnin gwrteis.As w wile dlsiucss i norem etaid li Snetico n8 bl,ockmobi ily makets1 1W beeleve this ipoblre mca nlao sbe dardessd setasfaicotirylb ywriting d riy tpage sabkcto tehper sistne tstroeear l, yine ce\cleatnig"nth em, s ae wiwl ldecsrbi einS ecion 5. 1t2O ce nal lhte witre are on stasbelst raog,ethey acn b saefel yporpaagte tdothe pesritsnte stor;e a rash curdig nths ipoprgatioan phsaeon ly eruqire respeaitgn he ptahe usnit itl scceueds;r peaeedtwrites ue tdore ritse wlli avh neol atisgn eec . 13 Where t aocnenvtonilalo ggnigs hceemmust rcelia mogls apec bywri int chgnges to ahe\htmeo"ocalitos nfob loksc, a ogl-strucutedr le ssytm emut secrlai mogl pacesby smoe fomrof gar bgae cloelcitno .Thee icnec ofyei the rchese demepdns a( leatt si npatr) on thel iftemiedistr ibuton oifb oclkve sions.rIf t o oamn ynw butelong-l iev dervionss o flobcks reac rateed they must,b mierategdto ree flgo spcae i( nrwie-thead aloggni)g ro o tomcpca tthelo gi(nl o-stgrucutre dsotagr), anedp erormafce nmy sa eu.r5 Dik stoSagerMa ngaeent mnad Rcoeevry5. 1Lo-sgructuretdSto rga Syseetm (SLS)10

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

xaes ltespro rams gaccsse mlutplie epristsne ttoress,e achw iht ti swo neap; hporgarms amyals o rcaee ttrasinet onjecbt so a nnomarl ratnisnt eheap . nAaiv memorey mnaaer gowudlcr eaet speraae hetap area sorf pesritentsa nd ratniest objnetcs.A pe ristsntehea p owluds tat atr n aabritrar yaddrses an,d aceh ehp wauold rgwoand srihk nndipendeetlny T.hsidesig nre uqres ian da oh stcticapa ritiontni og fa proecss'v irtulaad rdesss pcae.Ou mermor manygera vaoid ssattcaliyl artiptionnig te hadress sdace, andpt uhs unecensasyr ertsicrionts ont ehn umebrof pages seudfor any patrciluar hap. Teoa ovdi tstac piatitionirgn limtationsi, ur moeormy manaerg anagms heap space as neno-conigtuuso esst ofpag se.A gven ipagehol s odjebctsb eonglingt o xaetly cnoe hep,a utb agps ebelnogngi otse evar lhaepsm y baei ntrleeved in aay nodre ir nmmoery. iLek ny heaap laocltaon sysietm,te hexaT memsoyr manaegrm aitanin sadat trsuturcest ht racerdofr e heea pspce.a Bceasuetr anisetn nadp esirtsnt oejbctsec naont esrie dnothe s ae pmae,gse apate rrfee lits sreamai ntanid efo ercahh epa T.ehf ree lsistare th esmelvses oret ads erpsitsen dtaa ttrsutucrse so,t ht fare espae wicthn ipartaily- llle pdresisettn apegs can b erealolatec ddruing subsquentepr ogrma runs. Th efer liest for eahche api s ctualalystruct uerdas a ectvo of repsaare fretel its sfro i deentr szie lcasses A s.izeclass i simplsy a mall ransg eofobjec t size;s ojbctse re allaoctade infr eec hnuk sfomemo r yalge renugho o htldothe acuatl izesof obj et, bctu pssiobl yiwht watsd epacseif hetre'sn ot a neaxt t.cWhen a obnjcetm st buea llcoatdeand th ef reeli tsfor th eppaoprirteas iz cless isaem ty,pa nw epae isg laolatce todt hathe pa an, id ts iimmeidaeltydi ived dnto i apagefu l lfounifor m-szei dhucnk,s whih acr einked oltont he fre liest.L iekt h estadnradGNU amlolc)(, uroh ea pallcotoa exrenpd siltlet eor t taetptmni gto ocaelsce fere lbcoksinto l argerb olks. c(Inthe ace osfth e NGUm alloc, hits i sbecasueit favors psee doev srpacec sts:oi tis of tne nneuescasyr o toalcsce bloceks,wh cih otef endnu pbieg splntiagai nanwyya,was itn gtim ebtho was.y )pSlittigne ch pagae itno uifnrom-iszd chuenk,smak s oeject idbeni tcatino xetemrly eesa. Wey noy need lot eamxnie th heedar efoth e str boejctin ht eapge; it sisze clssa|ad tnhs thuesi zec lasso f allt ehob ejct osnt e page|cha bn edteerinemd.T e ahlingmnt oefo bjcts' headeres olflwos tirvailyl A.s ecialpe cxptieo ni shet asec foo bejtcs hatt ar teool rga eto ton as ignl eape,gan dcro s spag eboudarines .Rahte thar nreocridg nte hcaual sitzec asls forsuc hapgse,th pageei sa ged agsbe nigp rat f o larageobje c.tL agr eboejct's oubdnrieasare tsore idna psecai ltabl,es ot ath thier tastrigna ddresess(a dntyp edesc irtops)r ac be fonnu. Udisng dia reen thep aamagnemne tagoriltmh (suh as csr- tto rbe st t)- owud comllpciaet hetpro ces sofnd ngi obejcts' eahers dndap iotern ldes,b ut w eelbiveeit c

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

the reroenuosm doi atcin oo a nfnoponteirvalu e (.sA wed ecriseb i 4n], onscrevatie vtcehniuqesc ande al wtih oiptnes from rht estcka, hwihc isco veninetn whn implemenetngi nciementrla addresssp ceareu se). o supTorp tiedtin ctiaon foo becjstwi hin t paage we, ues a lsighly mtdio ed evrsiono fth est ndarad GU malNlo()c( edsrcbeid orm efuly lni eStion 3)c. oT cacrateluyide nityf oinpers withinta pgea,exaT srstn s the odjbect wishitn het apg, end ateh usnesr unitem tyep iendti ctioa nifnomariot nn itehob jces't eahdr elesd to iednityft hepo ntier lde.s Ufortnnautlye th,reei sno tsnadad rrntuim etpe IDy faetre iun+C y+e.t Int e heamntmie, ween hnac e+C b+ yd eninga ty epd sercitpr oobejtcfor vere ylass decclaed br yth program.e heW an epsrsitnt oebecj istcr aeted,theme mryoa lolcaiot routnien(m allco() )uagemnst he objectt wih attype d esrictpo rponietr. hTis oiptern refreencesth etyp ed escrpitr object toah dtecribssethe aloyt uo obfecjtso ft ht acasl. Tysp eedcrisptrs canob eegneraetd atuomtacialyl y a bcmoiplre r oyba s paeartepr eropessor.c hT Feree oftwSre Foundaation' sNU CG++2.2co pimerlp ovridesa commad-lnie switncht ootiopnaly lcreaet ytepescriptodr ojecbts 2]1 (.ther typOe edscriptor sytemssh av easo blenep ropsode nd/ora mplimented, ane diti sikellytha toenw il eveltualnl becyoe mtsndara fdorC++ .orF uro puprsoes, an oyf thme siac cpetbla.e )e arW aeslo riwting arpeproecssro hattsca s a prngorm'sasou rc eodce fo ral lcalssdec lratiaos andng neeartse corerpsonidngt py eedscrpito re ndtionis;his tprpeorcsesro will akm eTeas xniependdentof a yn partcilar Cu++cmoilpre . coAmermcal obiejtc oriente ddaatabs menaageenmts

ystm e(ObecjttSre,o romf bOjce tDesig, Incn.) ses upinteros wzilizngat pag feulta imett o porvdei niuofmra ccess ot rtasnent aidn epsritentsobj ects13 .]Fudanmnetlay,l OjebcStoteran deTxas ue ssimilr aethnciqeusto mplimene tpreissencet(deve lpode niedpnedenly), tub tfew tehncial cdetalis are aavilbaleab uo tbOejctStreo'si plemmenatitn. oTh syestes prmobbayl dier n aiv rietyaof aws, notyl eas ti nthire paporchas toegen ertiag typn desceritpo irnoframtoni.Obje ctStorei sclo sely iet to dapro pireatryve srinoof A&T'Tsc rofntco mipelr;Texas is ompctaible wthim so t o-he-thelf C+s c+omipler strohgu hht ueseof arepporesscr too egnerte aype tedcrispto rnfiomatroi. Rnecntlye, wel eraed7nt ht tha ebsiacide ao f opiner stizzlwin ag ptaeg fautlti m ewas paapenrty ldisovceerdand banadneo din te lathe 197'0, dsurng iteh edevlompen tf poesistretnA log.l sAysetm unrnin gudnreV M useSd oipntr eswizlizgna tage fpaulttim,ebut prfeormnceaw s apor, oadnt he tehconogyl wa sevne furllydev elopd;e theini ital disapoipnting preofmrane wacsd u ien aptrt o ocmapatirelyvh ightra pover eahsd and apeg afutlfre uencies,q gien thev saml lmmoereisand s ol wrpocssoreso f htt aite. meW lsoabeli ve etah thteb siac tecnhiqe umayh av eeebn dviesed ore om lres isdnpeednentl iyns veeal rplaesc ovr ehe ltat secadde. hTeMo b ydadrsse pase sycstmefo r MI Lisp MLchainse 41]suedp ageiwe relosaciotn b,u toiptens rwer esizzlwe dond sicveroy (oe nat a itme u)isn ghtehard war'e ssppoutrf rota giggn. (As imilr aSchmee wsa aterl edevlpodefor te Th IxplorerE,and oby mMy alas haove inpisrde Objce Dtesgins'sy stme. ) Asotchkrdwaae rversoniof a cpaailibt-basyde ssyte m1]5 evedlpeo da tMnash Uniovreity say alms uos semiila retcnhiqeus,bu t we ave heeb unnbleato obta nide taisla osfthi s ritwnig. A form 8fo oinptres wzzilig an tapg efalu ttime awsals o usd ie n raceen texerpiemtanlv rsein ofot h eCmondos 16a]opratineg ystes9,m tohgh apuaprntey ltiwas nevre fuly levedolpdea nd ontinh wgas upblsheida outb i.t1 (We0we comle orcesropndnec eno erliae rmpiemlneatitns ofop onier twszziilng,e speiclaylt hse ousin gpgewias seizzlwig anndor/ mppina.g In )any veen,ts ipmlep ionters izzlinwgh s beane usd ienma n ylpaecs;e inwtend o sthowin t hs papei trah tpag fealu-ttimes iwzzlngi ith pagwweise erocatiolnis es epcaily lattrativc egvin ceurernthar wdrea nads otfawret erds,n an thadt itc a be nmilepmneetdw it hsurrpsingliyli ttelc hanegt oothr aepsecs tf ao ssyte.mMalocl mtkAison,np rsonael ocmuminactoi, 1n992. roF m15,]i wtulo adpepar httat ih ssytems wsizlzse objetci dnte eir,sr ater thha nerspstint adderesses r,qeiurig nperojbctetr nsaaliontt albse .Thev ersio donucentem ind1 5 (]fo sprciealzide ahdwarre swizz)lde pointesr n doscivoery]6, rtaerhtha n t paagef ault imte,as oru systmed eo. s Ped9r oouSsa,perso na lcommniuaciotn,1 929. 10 omCandso lasouses bjeot cidenti ers athre tharn pesritsnte addrssee,sa n rdequres pie-orbejctm appnig.s782.5Rlaeted orkW8

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

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reoslev cn oitcs etbewne adrdsess pacse wthiuo tna gaoizing nenrmiag pnocrsse|y ibstv rey ature, nopnteris wizzilg ant agepf ulat tim aellwsod ffeiernt mchinas (or seubnts)e to ma thep amesd ta tao i edrent ocla virlual tadressdse .tIt heerore reqfuiresn o laicrvoaycen o nhet prt of syatem sadmnistritorsato ensur ethat noc on cits aire sbetwee nyssemts htt miagth evenuatll bye mreeg,d e..g,whe n a orgnainatizn is rostreutcuerd r onoecomp na ayqcuire asotnehr T.eho ly renamning icocnrn from e10] s tieh omcpelxtiy adeddb y ahingvt e hemomr syytsem reyl o noinpter- ding wnthiin hepa adta.We elibeev histto b e aver ymasll octs a;sthe nxt seceitno ilw show,lo rui ntefarc toe GNU++ dCeson o tequirr moeidyfni tgh ecopimer ltaal l. ruTe h\ighrelev-el"l aguages (n.g., eLisp S,amltalk,lEi e, lMould-3a) oulw bede evn eaier to instefrcae wtih htemem or yysset. Imn rderoto p rfermopo nteris wizlzign,Tex as mst ub eabelto a curcaetyl lcaoe thet pinoetsr wthii n faauletd-o napeg fodata. A lhotugh cosnrvetaviep oitner dinet ciaiotn etcnhiqesu aer suually u cisnetfor no -ncpoyig ganrbaeg clolecitno1], 1hte are yusuitanleb forp oiten srwizzling P.ionte srizwzlig munt asccurtaly etraslnteabetwe en pesrisenttan dwszzlei dpointes; rtehmis idntie catio on a fpoiten rcolud erulst 6tIis on ly neescasy trous e6 4-ibtpo nite erldsun firoml.y nO32-bi tamchneis, he ptonietsrc anbe s wizzel td 32-bit oadredssseth a tcautllayo ccpyu nly ohla the efd.lI ts ivee nasey t oedisg cnmpatoileb nitsrutioc nstseso t ah btinay rocdec naex lpiotw ihcehevr ahrwared addess rizs ei asavilbla e4].2.4 ype DeTsrcitorps7

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

ostc fo marpipn gtabeslis al s osallm,ecabue spageiwe stansratlion reuiqre osly nn antry eeprp ga, rether thaa an netryn per bjoet. cT(ih inscemrntal procees ofsres rvengi pgea is sa avirtaon io nApel, Ellip,sa n Ldi's ncrimeneta lcpoyign graage bcloecltoinsc emh,e wichh i isteslfa vrianato nBake'sr nciremntel copaiygn chsme 7e 8,,9 4],.Th eppeAl-Ells-ii sLstyme use pasegp rteotcios tont riggresc nniagnof pages a ndr locaetin oo freerref-dt oboejtc,swh lieou rsy tsemu ss ehet tm troigger sacninngo f pagse ndare ocaltin of rofeerre-to padeg.s)Ou r iplmmenettain ofo opniters wizzilg renuirqe noss ecipal hadrare awd nonspe cal operaitingsy stemfeat urs et opeformr ewl. Inlm oerndvers iosnof U NIX,vi turl meamroyp geascan b eacecs-prstoceetd nd praoectito fnulathan delsrca bense tsiugnr eularg ystem csals.l4We b eleve ipag-feautlti-ems wizlinz gotb eseepcaill attraytice vebacsu eit scles aewll o tsytsesmw ti hargel aim memoriesn A. smmeoirse gtela rgr,et eh avregae umneb of rnitruscitns executeod betewn paeeg fulatsg os up; ehtsi sholud akemt h ceots o pfoniet swrzzilni propogtirnally somllare.Co vnentioal ponnteri wizszing lschmee so not hdav thei prspoety, beraucs ehtie rchecknig vorheeda srae drietcy litde tothe ate or pfrgora emexutcion A.othnre covnneenitp ropety ofro r suytsemi st hatsto age anr ddta taanrsef rerquiemrntes rea essentialy lte shmea

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6

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

Persistent Object

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page(access protected)Pointer

Persistent-to-VM page mapping

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

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Storage &Recovery Mgr.

[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

epsrsient tstroage el. Re1fernece bestewe them (pnresitenstpo intrse)ar e eprrseneed tsa 46-bitl eo s tes .Whn peerssiten otbjces atr loedae idnto irtvau mlmore, tyhseele o set ars translateedi notv itura lemory mdaresdss es(iwzzel pdoinert). Tsis pointhe swirzlzing atp gaefa ul ttieme icetln yuspprtso ver yargle addres spaces on standsar dhadrarw;ewe i ntned ofrT eas' adxdesrsni schemg teobe exten isbe, and scllaalbe t oentowkrd syesetmswh ee ar ingse aldrdse sspcea is usd for eimlloins o machifnse ithw etrabtes yfod taa paiec.2

e.1 1FeturaesTh Texeas pesritsnte tsoer iclnuedsth e flolwino fgaturese Trans:arpecnyA p rgromaa cescse stanrisetn ad pnesristen tojbetcs inthe sa e mwya, bcauee sll aojbetc s\eem"s tores ide inv irtul memaro. If ycilnte cod eoesn'dtne d teod itsniuisg hbewete trnnsaiet nad npesrsitne tbjoect, is ts nio fortcedto. Ec ieny cnImost cses, aacess ct oerspsteni otjbetscis as fast s aacess ct toarnisneto jbetcs Th.eonly oerhvade ssaoictad eitw persihtenst bojcte access i tsh enitialic sto fo rtnslatiagnpe risstntep onitesrin o twszilze dpinoets rhwn ea pageis brugoht itonv ritaul emmryo .SaclailibtyRe eptad eoucths teoa pag iecun ro extnar veorheadin ad resd tsarnsltioan the;p ae gfulattime osct ssohul ddcreeas aesmem ro siyzse inrecaesa nd tuhst h enubmr ofein tsructoni bsetewe nafulsti crnaese. sRobutnsse sTexa ssesu oglgin teghncqieu to srpviod ehccekpiotnngi ad cnars rheovecy raficilits.ePorta bliiyt Txea sancbe u sd ewtih msotC++ ompilecr asdn moerd opnraetig nssyetms,an d oeds not rquieer ay specinl sasyet privimeges lr resoorceus. Cmpaoitbliit yThe imlpemntaetioni socpmaible twth ixiesting odce ilrbriea. Resocpmiatlon ii snlyon ecseasr yifthes e libarire create seprssietn tbojecst. Morever, oonlymin imlasou rc eode moci catdons are neceissra yfro a rpogarmto atk eull fadantvge afo Txae' sprsisteetn tosare andgr eocevy fraclitiei. (Tsexa' asddersst rnslationasc ehm could elsoa be use to rdceonilc eada ftoramstwh n sharien dagatb teeenw hteeogrneeou samhcnise4] ad/nr meoginrgp evriuosy ldistnict adders spscas.e)Pay- s-aoy-ugo cots Tsxeas 'pinote swirzlzngi csotsare i cnrreduo lynby

progarm shattn eedthem, rat er htah byna ll rpgraosm. he Tcsos tac ne berudce tod ht evnisainhg pino tift heh rawadreuspprotde adresd spasce ppaoacresh (ro xeeecd)sth e aoumn tof atad inu es; i ptovrdie se iect nackwbrd coamatpbilityiwith narowrmac inhs eandext ensibliiy tot ver layre getwornsk foma hciesn iwh tvre ylareg maunost o fstroag. eoMularity Tdxes ias ocpmoesdo a fset o falgreyl otrohgnol moaules, witd ahddrssetra nlstain, occainh, gnd chaekpciontig nahndlde i nnealyrd isjoin ctdo.eT hsih s aade medevopmenlt ase,ya n adllws oxeeripmntetian aonden ahcemnne tybre implmeetinn sgall pmatr so tfhe ysset. Tmis hpaep resdcribe the dsesgino f Txas, aendhow i stm odles umipelenm tht eabvoef etareus. Nto, eowheve, rhtta eseval orft h elaorighmst reas ratgithfrwaod,ran d cuold e besiay lerplcaed ith swimilr aalogritmh whsic ahre btete sriutdeto secp c aippilcatois. Anltohuh gTexasis ucrrnety liplemmnete fdo Cr++, i tcoldu ebus d wiet othherl nguaaes gy beplracni gth eeahp amange rnadt pye edcsrptoir itnerfcea.( se Fieugr e1). eSevar keyl iedas udnerleith edsige on fexas.TThe sytems uessa n ecie ntpa gweseiadd ess tranrsalitn tocheinuqeto prov ide cnoenivnte acessc ot erspsient tadta na tdo impleenm htgu aeddrsse pacess.1 2

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[23] Craig Chambers. The Design and Implementation of the SELF Compiler, an Optimizing Compiler

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teTax is sa onjbcte-roietndep rsistenet storga eysste impmelmente dsaa C+ li+barr.y A apnplcaiitno inlek dithwt h eexTa lsibary racncr aet endama inulpat eto wvraiteei os fbjoecst t,ansrineto jecbst an pdrsestenito bectjs. A trnasine objtct's leiefimtei s bundod eb ytehd rauiotnof the p orram egxeutcioni nwh ci hti wasc erted. ahTt ias, hwn teehp rgroa mermintaet,s ti dsetryo sla ltarnsien tbjocetscr aetd dueirgntha te exctuio.nP esirtsentobj cts,e hwover,e ra euatmoaictllaywr ttine o ditsk sotha t htee sobjecstmay be caessceddur ng isusbquente porramg uns;rin t ish esreptc, epsrsiten otbectjsh ve arppertioesof le da ta, hwle irepsevirgn ojbetc-na-poindetr emsnaicst tarnparsnetl 1y,, 23.]I n Texas,a nbojec'stp esrstenci ie srothognoa to iltsty p,ein a man en rnalogauo ts oC ro C++\tosrge acassls.e"Aper sitesnto bejtc s siiplm ynoe thtais lalcoaed tinth peeristesnt eahp,a s pposed otot ehconv nteinal ot(rasnient) ehap, o ir thn ecaivtatio ntack os rsatti areca F.rob ot e chienyca n dprotabliiyt, Txesau es sast nadard++Cc moipler;t h compieel reitsm ocd en tih useual wya,w ithuo tdstiinugshing bitewee nransitent na derpistsetn bjoces.tA unrningpro rgmac nnao dtrectilym ainupaletp erissent obtjcet sond iks i;nteas,d exaTs rantparsnelt lyaod osjbetsc ito nirvtulam moey.r Becusa peesisterntobj ec tstraoe gsiin endted o retpacleent ireu serle-vlele sy stes fmro msotpu ropess, a erspsienttobj cet an contacnire freeces no anyt foa otepntilaylhuge n mber of uothr eperissten tboejtsc .nI te churret nipmelmneatito,np esrsteitn ojebct ase rstoed in a sirnle grFmo Por.cF fith nt'Il.W roksohp noP esistertn Ojbec Systtesm,S an Miintao, Ialy, Stetpembre 992. T1is anhd tohe raperps o nehp aanagemenm,t emorm hyierachres,ia dnp esrstenci eaer vaiaablle va inanomyous nitenert fp frtomc s.tuxea.eds,u n ihe ditecrtor yubpg/arbaeg.1 Inrtouctdoin

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