1 (* copyright 1999 YALE FLINT project *)
2 (* monnier@cs.yale.edu *)
4 (let val a = 1 val b = 2
25 datatype foo = FOO | BAR of baz
26 and baz = BAZ | QUUX of foo
30 and baz = BAZ (* fixindent *)
34 datatype foo = datatype M.foo
37 signature S = S' where type foo = int
42 , let val x = f 42 in g (x,x,44) end
46 , let val x = f 42 in g (x,x,44) end
47 , foldl (fn ((p,q),s) => g (p,q,Vector.length q) ^ ":" ^ s)
48 "" (Beeblebrox.masterCountList mlist2)
49 , if null mlist2 then ";" else ""
55 = let val _ = 1 in 2 end
76 F.APP(F.VAR fl, OU.filter filt vs)
125 structure Foo = struct
131 type flint = FLINT.prog
132 val split: flint -> flint * flint option
135 structure FSplit :> FSPLIT =
140 structure S = IntRedBlackSet
141 structure M = FLINTIntMap
143 structure OU = OptUtils
144 structure FU = FlintUtil
145 structure LT = LtyExtern
146 structure PO = PrimOp
147 structure PP = PPFlint
148 structure CTRL = FLINT_Control
151 val say = Control_Print.say
152 fun bug msg = ErrorMsg.impossible ("FSplit: "^msg)
153 fun buglexp (msg,le) = (say "\n"; PP.printLexp le; say " "; bug msg)
154 fun bugval (msg,v) = (say "\n"; PP.printSval v; say " "; bug msg)
155 fun assert p = if p then () else bug ("assertion failed")
158 val mklv = LambdaVar.mkLvar
159 val cplv = LambdaVar.dupLvar
161 fun S_rmv(x, s) = S.delete(s, x) handle NotFound => s
163 fun addv (s,F.VAR lv) = S.add(s, lv)
165 fun addvs (s,vs) = foldl (fn (v,s) => addv(s, v)) s vs
166 fun rmvs (s,lvs) = foldl (fn (l,s) => S_rmv(l, s)) s lvs
170 fun split (fdec as (fk,f,args,body)) = let
171 val {getLty,addLty,...} = Recover.recover (fdec, false)
173 val m = Intmap.new(64, Unknown)
174 fun addpurefun f = Intmap.add m (f, false)
175 fun funeffect f = (Intmap.map m f) handle Uknown => true
177 (* sexp: env -> lexp -> (leE, leI, fvI, leRet)
178 * - env: IntSetF.set current environment
179 * - lexp: lexp expression to split
180 * - leRet: lexp the core return expression of lexp
181 * - leE: lexp -> lexp recursively split lexp: leE leRet == lexp
182 * - leI: lexp option inlinable part of lexp (if any)
183 * - fvI: IntSetF.set free variables of leI: FU.freevars leI == fvI
185 * sexp splits the lexp into an expansive part and an inlinable part.
186 * The inlinable part is guaranteed to be side-effect free.
187 * The expansive part doesn't bother to eliminate unused copies of
188 * elements copied to the inlinable part.
189 * If the inlinable part cannot be constructed, leI is set to F.RET[].
190 * This implies that fvI == S.empty, which in turn prevents us from
191 * mistakenly adding anything to leI.
193 fun sexp env lexp = (* fixindent *)
195 (* non-side effecting binds are copied to leI if exported *)
196 fun let1 (le,lewrap,lv,vs,effect) =
197 let val (leE,leI,fvI,leRet) = sexp (S.add(env, lv)) le
198 val leE = lewrap o leE
199 in if effect orelse not (S.member(fvI, lv))
200 then (leE, leI, fvI, leRet)
201 else (leE, lewrap leI, addvs(S_rmv(lv, fvI), vs), leRet)
205 (* we can completely move both RET and TAPP to the I part *)
206 of F.RECORD (rk,vs,lv,le as F.RET [F.VAR lv']) =>
208 then (fn e => e, lexp, addvs(S.empty, vs), lexp)
209 else (fn e => e, le, S.singleton lv', le)
211 (fn e => e, lexp, addvs(S.empty, vs), lexp)
212 | F.TAPP (F.VAR tf,tycs) =>
213 (fn e => e, lexp, S.singleton tf, lexp)
215 (* recursive splittable lexps *)
216 | F.FIX (fdecs,le) => sfix env (fdecs, le)
217 | F.TFN (tfdec,le) => stfn env (tfdec, le)
220 | F.CON (dc,tycs,v,lv,le) =>
221 let1(le, fn e => F.CON(dc, tycs, v, lv, e), lv, [v], false)
222 | F.RECORD (rk,vs,lv,le) =>
223 let1(le, fn e => F.RECORD(rk, vs, lv, e), lv, vs, false)
224 | F.SELECT (v,i,lv,le) =>
225 let1(le, fn e => F.SELECT(v, i, lv, e), lv, [v], false)
226 | F.PRIMOP (po,vs,lv,le) =>
227 let1(le, fn e => F.PRIMOP(po, vs, lv, e), lv, vs, PO.effect(#2 po))
229 (* IMPROVEME: lvs should not be restricted to [lv] *)
230 | F.LET(lvs as [lv],body as F.TAPP (v,tycs),le) =>
231 let1(le, fn e => F.LET(lvs, body, e), lv, [v], false)
232 | F.LET (lvs as [lv],body as F.APP (v as F.VAR f,vs),le) =>
233 let1(le, fn e => F.LET(lvs, body, e), lv, v::vs, funeffect f)
235 | F.SWITCH (v,ac,[(dc as F.DATAcon(_,_,lv),le)],NONE) =>
236 let1(le, fn e => F.SWITCH(v, ac, [(dc, e)], NONE), lv, [v], false)
238 | F.LET (lvs,body,le) =>
239 let val (leE,leI,fvI,leRet) = sexp (S.union(S.addList(S.empty, lvs), env)) le
240 in (fn e => F.LET(lvs, body, leE e), leI, fvI, leRet)
243 (* useless sophistication *)
244 | F.APP (F.VAR f,args) =>
246 then (fn e => e, F.RET[], S.empty, lexp)
247 else (fn e => e, lexp, addvs(S.singleton f, args), lexp)
249 (* other non-binding lexps result in unsplittable functions *)
250 | (F.APP _ | F.TAPP _) => bug "strange (T)APP"
251 | (F.SWITCH _ | F.RAISE _ | F.BRANCH _ | F.HANDLE _) =>
252 (fn e => e, F.RET[], S.empty, lexp)
255 (* Functions definitions fall into the following categories:
256 * - inlinable: if exported, copy to leI
257 * - (mutually) recursive: don't bother
258 * - non-inlinable non-recursive: split recursively *)
259 and sfix env (fdecs,le) =
260 let val nenv = S.union(S.addList(S.empty, map #2 fdecs), env)
261 val (leE,leI,fvI,leRet) = sexp nenv le
262 val nleE = fn e => F.FIX(fdecs, leE e)
264 of [({inline=inl as (F.IH_ALWAYS | F.IH_MAYBE _),...},f,args,body)] =>
265 let val min = case inl of F.IH_MAYBE(n,_) => n | _ => 0
266 in if not(S.member(fvI, f)) orelse min > !CTRL.splitThreshold
267 then (nleE, leI, fvI, leRet)
268 else (nleE, F.FIX(fdecs, leI),
269 rmvs(S.union(fvI, FU.freevars body),
273 | [fdec as (fk as {cconv=F.CC_FCT,...},_,_,_)] =>
274 sfdec env (leE,leI,fvI,leRet) fdec
276 | _ => (nleE, leI, fvI, leRet)
279 and sfdec env (leE,leI,fvI,leRet) (fk,f,args,body) =
280 let val benv = S.union(S.addList(S.empty, map #1 args), env)
281 val (bodyE,bodyI,fvbI,bodyRet) = sexp benv body
284 (fn e => F.FIX([(fk, f, args, bodyE bodyRet)], e),
287 let val fvbIs = S.listItems(S.difference(fvbI, benv))
288 val (nfk,fkE) = OU.fk_wrap(fk, NONE)
292 val fErets = (map F.VAR fvbIs)
293 val bodyE = bodyE(F.RET fErets)
295 val bodyE = bodyE(F.RECORD(F.RK_STRUCT, map F.VAR fvbIs,
296 tmp, F.RET[F.VAR tmp])) *)
297 val fdecE = (fkE, fE, args, bodyE)
298 val fElty = LT.ltc_fct(map #2 args, map getLty fErets)
299 val _ = addLty(fE, fElty)
302 val fkI = {inline=F.IH_ALWAYS, cconv=F.CC_FCT,
303 known=true, isrec=NONE}
305 (map (fn lv => (lv, getLty(F.VAR lv))) fvbIs) @ args
306 val fdecI as (_,fI,_,_) = FU.copyfdec(fkI,f,argsI,bodyI)
307 val _ = addpurefun fI
310 val nargs = map (fn (v,t) => (cplv v, t)) args
311 val argsv = map (fn (v,t) => F.VAR v) nargs
313 let val lvs = map cplv fvbIs
314 in F.LET(lvs, F.APP(F.VAR fE, argsv),
315 F.APP(F.VAR fI, (map F.VAR lvs)@argsv))
317 (* let val lv = mklv()
318 in F.LET([lv], F.APP(F.VAR fE, argsv),
319 F.APP(F.VAR fI, (F.VAR lv)::argsv))
321 val nfdec = (nfk, f, nargs, nbody)
323 (* and now, for the whole F.FIX *)
325 F.FIX([fdecE], F.FIX([fdecI], F.FIX([nfdec], leE e)))
327 in if not(S.member(fvI, f)) then (nleE, leI, fvI, leRet)
329 F.FIX([fdecI], F.FIX([nfdec], leI)),
330 S.add(S.union(S_rmv(f, fvI), S.intersection(env, fvbI)), fE),
335 (* TFNs are kinda like FIX except there's no recursion *)
336 and stfn env (tfdec as (tfk,tf,args,body),le) =
337 let val (bodyE,bodyI,fvbI,bodyRet) =
338 if #inline tfk = F.IH_ALWAYS
339 then (fn e => body, body, FU.freevars body, body)
341 val nenv = S.add(env, tf)
342 val (leE,leI,fvI,leRet) = sexp nenv le
343 in case (bodyI, S.listItems(S.difference(fvbI, env)))
344 of ((F.RET _ | F.RECORD(_,_,_,F.RET _)),_) =>
346 (fn e => F.TFN((tfk, tf, args, bodyE bodyRet), leE e),
349 (* everything was split out *)
350 let val ntfdec = ({inline=F.IH_ALWAYS}, tf, args, bodyE bodyRet)
351 val nlE = fn e => F.TFN(ntfdec, leE e)
352 in if not(S.member(fvI, tf)) then (nlE, leI, fvI, leRet)
353 else (nlE, F.TFN(ntfdec, leI),
354 S_rmv(tf, S.union(fvI, fvbI)), leRet)
359 val tfEvs = map F.VAR fvbIs
360 val bodyE = bodyE(F.RET tfEvs)
361 val tfElty = LT.lt_nvpoly(args, map getLty tfEvs)
362 val _ = addLty(tfE, tfElty)
365 val tfkI = {inline=F.IH_ALWAYS}
366 val argsI = map (fn (v,k) => (cplv v, k)) args
367 (* val tmap = ListPair.map (fn (a1,a2) =>
368 * (#1 a1, LT.tcc_nvar(#1 a2)))
370 val bodyI = FU.copy tmap M.empty
371 (F.LET(fvbIs, F.TAPP(F.VAR tfE, map #2 tmap),
375 F.TFN((tfk, tfE, args, bodyE),
376 F.TFN((tfkI, tf, argsI, bodyI), leE e))
378 in if not(S.member(fvI, tf)) then (nleE, leI, fvI, leRet)
380 F.TFN((tfkI, tf, argsI, bodyI), leI),
381 S.add(S.union(S_rmv(tf, fvI), S.intersection(env, fvbI)), tfE),
386 (* here, we use B-decomposition, so the args should not be
387 * considered as being in scope *)
388 val (bodyE,bodyI,fvbI,bodyRet) = sexp S.empty body
389 in case (bodyI, bodyRet)
390 of (F.RET _,_) => ((fk, f, args, bodyE bodyRet), NONE)
391 | (_,F.RECORD (rk,vs,lv,F.RET[lv'])) =>
392 let val fvbIs = S.listItems fvbI
395 val bodyE = bodyE(F.RECORD(rk, vs@(map F.VAR fvbIs), lv, F.RET[lv']))
396 val fdecE as (_,fE,_,_) = (fk, cplv f, args, bodyE)
400 val argLtys = (map getLty vs) @ (map (getLty o F.VAR) fvbIs)
401 val argsI = [(argI, LT.ltc_str argLtys)]
402 val (_,bodyI) = foldl (fn (lv,(n,le)) =>
403 (n+1, F.SELECT(F.VAR argI, n, lv, le)))
404 (length vs, bodyI) fvbIs
405 val fdecI as (_,fI,_,_) = FU.copyfdec (fk, f, argsI, bodyI)
407 val nargs = map (fn (v,t) => (cplv v, t)) args
414 F.APP(F.VAR fE, map (F.VAR o #1) nargs),
415 F.APP(F.VAR fI, [F.VAR argI]))))),
419 | _ => (fdec, NONE) (* sorry, can't do that *)
420 (* (PPFlint.printLexp bodyRet; bug "couldn't find the returned record") *)