## Mercurial > urweb

### diff src/sqlcache.sml @ 2248:e09c3dc102ef

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Rewrite effectfulness analysis using MonoUtil.

author | Ziv Scully <ziv@mit.edu> |
---|---|

date | Sat, 15 Aug 2015 23:08:37 -0700 |

parents | e4a7e3cd6f11 |

children | c275bbc41194 |

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line diff

--- a/src/sqlcache.sml Sun Aug 02 18:37:24 2015 -0700 +++ b/src/sqlcache.sml Sat Aug 15 23:08:37 2015 -0700 @@ -43,100 +43,82 @@ fun setCache c = cache := c fun getCache () = !cache +(* Used to have type context for local variables in MonoUtil functions. *) +val doBind = + fn (ctx, MonoUtil.Exp.RelE (_, t)) => t :: ctx + | (ctx, _) => ctx -(* Effect analysis. *) + +(*******************) +(* Effect Analysis *) +(*******************) (* Makes an exception for [EWrite] (which is recorded when caching). *) -fun effectful doPrint (effs : IS.set) (inFunction : bool) (bound : int) : exp -> bool = - (* If result is true, expression is definitely effectful. If result is - false, then expression is definitely not effectful if effs is fully - populated. The intended pattern is to use this a number of times equal - to the number of declarations in a file, Bellman-Ford style. *) - (* TODO: make incrementing of the number of bound variables cleaner, - probably by using [MonoUtil] instead of all this. *) +fun effectful (effs : IS.set) = let - (* DEBUG: remove printing when done. *) - fun tru msg = if doPrint then (print (msg ^ "\n"); true) else true - val rec eff' = - (* ASK: is there a better way? *) - fn EPrim _ => false - (* We don't know if local functions have effects when applied. *) - | ERel idx => if inFunction andalso idx >= bound - then tru ("rel" ^ Int.toString idx) else false - | ENamed name => if IS.member (effs, name) then tru "named" else false - | ECon (_, _, NONE) => false - | ECon (_, _, SOME e) => eff e - | ENone _ => false - | ESome (_, e) => eff e - | EFfi (m, f) => if ffiEffectful (m, f) then tru "ffi" else false - | EFfiApp (m, f, _) => if ffiEffectful (m, f) then tru "ffiapp" else false - (* ASK: we're calling functions effectful if they have effects when - applied or if the function expressions themselves have effects. - Is that okay? *) - (* This is okay because the values we ultimately care about aren't - functions, and this is a conservative approximation, anyway. *) - | EApp (eFun, eArg) => effectful doPrint effs true bound eFun orelse eff eArg - | EAbs (_, _, _, e) => effectful doPrint effs inFunction (bound+1) e - | EUnop (_, e) => eff e - | EBinop (_, _, e1, e2) => eff e1 orelse eff e2 - | ERecord xs => List.exists (fn (_, e, _) => eff e) xs - | EField (e, _) => eff e - (* If any case could be effectful, consider it effectful. *) - | ECase (e, xs, _) => eff e orelse List.exists (fn (_, e) => eff e) xs - | EStrcat (e1, e2) => eff e1 orelse eff e2 - (* ASK: how should we treat these three? *) - | EError _ => tru "error" - | EReturnBlob _ => tru "blob" - | ERedirect _ => tru "redirect" - (* EWrite is a special exception because we record writes when caching. *) - | EWrite _ => false - | ESeq (e1, e2) => eff e1 orelse eff e2 - (* TODO: keep context of which local variables aren't effectful? Only - makes a difference for function expressions, though. *) - | ELet (_, _, eBind, eBody) => eff eBind orelse - effectful doPrint effs inFunction (bound+1) eBody - | EClosure (_, es) => List.exists eff es - (* TODO: deal with EQuery. *) - | EQuery _ => tru "query" - | EDml _ => tru "dml" - | ENextval _ => tru "nextval" - | ESetval _ => tru "setval" - | EUnurlify (e, _, _) => eff e - (* ASK: how should we treat this? *) - | EJavaScript _ => tru "javascript" - (* ASK: these are all effectful, right? *) - | ESignalReturn _ => tru "signalreturn" - | ESignalBind _ => tru "signalbind" - | ESignalSource _ => tru "signalsource" - | EServerCall _ => tru "servercall" - | ERecv _ => tru "recv" - | ESleep _ => tru "sleep" - | ESpawn _ => tru "spawn" - and eff = fn (e', _) => eff' e' + val isFunction = + fn (TFun _, _) => true + | _ => false + fun doExp (ctx, e) = + case e of + EPrim _ => false + (* For now: variables of function type might be effectful, but + others are fully evaluated and are therefore not effectful. *) + | ERel n => isFunction (List.nth (ctx, n)) + | ENamed n => IS.member (effs, n) + | EFfi (m, f) => ffiEffectful (m, f) + | EFfiApp (m, f, _) => ffiEffectful (m, f) + (* These aren't effectful unless a subexpression is. *) + | ECon _ => false + | ENone _ => false + | ESome _ => false + | EApp _ => false + | EAbs _ => false + | EUnop _ => false + | EBinop _ => false + | ERecord _ => false + | EField _ => false + | ECase _ => false + | EStrcat _ => false + (* EWrite is a special exception because we record writes when caching. *) + | EWrite _ => false + | ESeq _ => false + | ELet _ => false + (* ASK: what should we do about closures? *) + | EClosure _ => false + | EUnurlify _ => false + (* Everything else is some sort of effect. We could flip this and + explicitly list bits of Mono that are effectful, but this is + conservatively robust to future changes (however unlikely). *) + | _ => true in - eff + MonoUtil.Exp.existsB {typ = fn _ => false, exp = doExp, bind = doBind} end (* TODO: test this. *) -val effectfulMap = +fun effectfulDecls (decls, _) = let - fun doVal ((_, name, _, e, _), effMap) = - if effectful false effMap false 0 e - then IS.add (effMap, name) - else effMap + fun doVal ((_, name, _, e, _), effs) = + if effectful effs [] e + then IS.add (effs, name) + else effs val doDecl = - fn (DVal v, effMap) => doVal (v, effMap) - (* Repeat the list of declarations a number of times equal to its size. *) - | (DValRec vs, effMap) => - List.foldl doVal effMap (List.concat (List.map (fn _ => vs) vs)) + fn ((DVal v, _), effs) => doVal (v, effs) + (* Repeat the list of declarations a number of times equal to its size, + making sure effectfulness propagates everywhere it should. This is + analagous to the Bellman-Ford algorithm. *) + | ((DValRec vs, _), effs) => + List.foldl doVal effs (List.concat (List.map (fn _ => vs) vs)) (* ASK: any other cases? *) - | (_, effMap) => effMap + | (_, effs) => effs in - MonoUtil.File.fold {typ = #2, exp = #2, decl = doDecl} IS.empty + List.foldl doDecl IS.empty decls end -(* Boolean formula normalization. *) +(*********************************) +(* Boolean Formula Normalization *) +(*********************************) datatype junctionType = Conj | Disj @@ -211,7 +193,9 @@ | Combo (j, fs) => Combo (j, map (mapFormula mf) fs) -(* SQL analysis. *) +(****************) +(* SQL Analysis *) +(****************) structure CmpKey = struct @@ -464,7 +448,9 @@ | Sql.Update (tab, _, _) => tab -(* Program instrumentation. *) +(***************************) +(* Program Instrumentation *) +(***************************) val varName = let @@ -477,6 +463,8 @@ val dummyLoc = ErrorMsg.dummySpan +val dummyTyp = (TRecord [], dummyLoc) + fun stringExp s = (EPrim (Prim.String (Prim.Normal, s)), dummyLoc) val stringTyp = (TFfi ("Basis", "string"), dummyLoc) @@ -490,17 +478,15 @@ end | _ => raise Match -(* Always increments negative indices because that's what we need later. *) -fun incRelsBound bound inc = +(* Always increments negative indices as a hack we use later. *) +fun incRels inc = MonoUtil.Exp.mapB - {typ = fn x => x, - exp = fn level => - (fn ERel n => ERel (if n >= level orelse n < 0 then n + inc else n) - | x => x), - bind = fn (level, MonoUtil.Exp.RelE _) => level + 1 | (level, _) => level} - bound - -val incRels = incRelsBound 0 + {typ = fn t' => t', + exp = fn bound => + (fn ERel n => ERel (if n >= bound orelse n < 0 then n + inc else n) + | e' => e'), + bind = fn (bound, MonoUtil.Exp.RelE _) => bound + 1 | (bound, _) => bound} + 0 fun cacheWrap (query, i, urlifiedRel0, resultTyp, args) = let @@ -523,13 +509,16 @@ end fun fileMapfold doExp file start = - case MonoUtil.File.mapfold {typ = Search.return2, - exp = fn x => (fn s => Search.Continue (doExp x s)), - decl = Search.return2} file start of + case MonoUtil.File.mapfoldB + {typ = Search.return2, + exp = fn ctx => fn e' => fn s => Search.Continue (doExp ctx e' s), + decl = fn _ => Search.return2, + bind = doBind} + [] file start of Search.Continue x => x | Search.Return _ => raise Match -fun fileMap doExp file = #1 (fileMapfold (fn x => fn _ => (doExp x, ())) file ()) +fun fileMap doExp file = #1 (fileMapfold (fn _ => fn e => fn _ => (doExp e, ())) file ()) fun factorOutNontrivial text = let @@ -567,7 +556,7 @@ fun addChecking file = let - fun doExp (queryInfo as (tableToIndices, indexToQueryNumArgs, index)) = + fun doExp ctx (queryInfo as (tableToIndices, indexToQueryNumArgs, index)) = fn e' as EQuery {query = origQueryText, sqlcacheInfo = urlifiedRel0, state = resultTyp, @@ -590,8 +579,12 @@ val args = List.tabulate (numArgs, fn n => (ERel n, dummyLoc)) fun bind x f = Option.mapPartial f x fun guard b x = if b then x else NONE - (* DEBUG: set first boolean argument to true to turn on printing. *) - fun safe bound = not o effectful true (effectfulMap file) false bound + val effs = effectfulDecls file + (* We use dummyTyp here. I think this is okay because databases + don't store (effectful) functions, but there could be some + corner case I missed. *) + fun safe bound = + not o effectful effs (List.tabulate (bound, fn _ => dummyTyp) @ ctx) val attempt = (* Ziv misses Haskell's do notation.... *) guard (safe 0 queryText andalso safe 0 initial andalso safe 2 body) ( @@ -609,7 +602,9 @@ end | e' => (e', queryInfo) in - fileMapfold (fn exp => fn state => doExp state exp) file (SIMM.empty, IM.empty, 0) + fileMapfold (fn ctx => fn exp => fn state => doExp ctx state exp) + file + (SIMM.empty, IM.empty, 0) end structure Invalidations = struct