Mercurial > urweb

annotate src/mono_reduce.sml @ 280:fdd7a698be01

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Compiling a parametrized query the inefficient way
author Adam Chlipala <adamc@hcoop.net>
date Tue, 02 Sep 2008 17:31:45 -0400
parents bacd0ba869e1
children c0e4ac23522d
rev   line source
adamc@133 1 (* Copyright (c) 2008, Adam Chlipala
adamc@133 2 * All rights reserved.
adamc@133 3 *
adamc@133 4 * Redistribution and use in source and binary forms, with or without
adamc@133 5 * modification, are permitted provided that the following conditions are met:
adamc@133 6 *
adamc@133 7 * - Redistributions of source code must retain the above copyright notice,
adamc@133 8 * this list of conditions and the following disclaimer.
adamc@133 9 * - Redistributions in binary form must reproduce the above copyright notice,
adamc@133 10 * this list of conditions and the following disclaimer in the documentation
adamc@133 11 * and/or other materials provided with the distribution.
adamc@133 12 * - The names of contributors may not be used to endorse or promote products
adamc@133 13 * derived from this software without specific prior written permission.
adamc@133 14 *
adamc@133 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@133 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@133 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@133 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@133 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
adamc@133 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@133 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@133 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@133 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@133 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@133 25 * POSSIBILITY OF SUCH DAMAGE.
adamc@133 26 *)
adamc@133 27
adamc@133 28 (* Simplify a Mono program algebraically *)
adamc@133 29
adamc@133 30 structure MonoReduce :> MONO_REDUCE = struct
adamc@133 31
adamc@133 32 open Mono
adamc@133 33
adamc@133 34 structure E = MonoEnv
adamc@133 35 structure U = MonoUtil
adamc@133 36
adamc@133 37
adamc@252 38 fun impure (e, _) =
adamc@252 39 case e of
adamc@252 40 EWrite _ => true
adamc@252 41 | EQuery _ => true
adamc@252 42 | EAbs _ => false
adamc@252 43
adamc@252 44 | EPrim _ => false
adamc@252 45 | ERel _ => false
adamc@252 46 | ENamed _ => false
adamc@252 47 | ECon (_, _, eo) => (case eo of NONE => false | SOME e => impure e)
adamc@252 48 | EFfi _ => false
adamc@252 49 | EFfiApp _ => false
adamc@252 50 | EApp ((EFfi _, _), _) => false
adamc@252 51 | EApp _ => true
adamc@252 52
adamc@252 53 | ERecord xes => List.exists (fn (_, e, _) => impure e) xes
adamc@252 54 | EField (e, _) => impure e
adamc@252 55
adamc@252 56 | ECase (e, pes, _) => impure e orelse List.exists (fn (_, e) => impure e) pes
adamc@252 57
adamc@252 58 | EStrcat (e1, e2) => impure e1 orelse impure e2
adamc@252 59
adamc@252 60 | ESeq (e1, e2) => impure e1 orelse impure e2
adamc@252 61 | ELet (_, _, e1, e2) => impure e1 orelse impure e2
adamc@252 62
adamc@252 63 | EClosure (_, es) => List.exists impure es
adamc@252 64
adamc@252 65
adamc@252 66 val liftExpInExp = Monoize.liftExpInExp
adamc@252 67
adamc@252 68 val subExpInExp' =
adamc@133 69 U.Exp.mapB {typ = fn t => t,
adamc@133 70 exp = fn (xn, rep) => fn e =>
adamc@133 71 case e of
adamc@133 72 ERel xn' =>
adamc@133 73 (case Int.compare (xn', xn) of
adamc@133 74 EQUAL => #1 rep
adamc@133 75 | GREATER=> ERel (xn' - 1)
adamc@133 76 | LESS => e)
adamc@133 77 | _ => e,
adamc@133 78 bind = fn ((xn, rep), U.Exp.RelE _) => (xn+1, liftExpInExp 0 rep)
adamc@133 79 | (ctx, _) => ctx}
adamc@133 80
adamc@252 81 fun subExpInExp (n, e1) e2 =
adamc@252 82 let
adamc@252 83 val r = subExpInExp' (n, e1) e2
adamc@252 84 in
adamc@252 85 (*Print.prefaces "subExpInExp" [("e1", MonoPrint.p_exp MonoEnv.empty e1),
adamc@252 86 ("e2", MonoPrint.p_exp MonoEnv.empty e2),
adamc@252 87 ("r", MonoPrint.p_exp MonoEnv.empty r)];*)
adamc@252 88 r
adamc@252 89 end
adamc@133 90
adamc@133 91 fun typ c = c
adamc@133 92
adamc@258 93 datatype result = Yes of E.env | No | Maybe
adamc@258 94
adamc@183 95 fun match (env, p : pat, e : exp) =
adamc@183 96 case (#1 p, #1 e) of
adamc@258 97 (PWild, _) => Yes env
adamc@258 98 | (PVar (x, t), _) => Yes (E.pushERel env x t (SOME e))
adamc@183 99
adamc@280 100 | (PPrim (Prim.String s), EStrcat ((EPrim (Prim.String s'), _), _)) =>
adamc@280 101 if String.isPrefix s' s then
adamc@280 102 Maybe
adamc@280 103 else
adamc@280 104 No
adamc@280 105
adamc@183 106 | (PPrim p, EPrim p') =>
adamc@183 107 if Prim.equal (p, p') then
adamc@258 108 Yes env
adamc@183 109 else
adamc@258 110 No
adamc@183 111
adamc@188 112 | (PCon (_, PConVar n1, NONE), ECon (_, PConVar n2, NONE)) =>
adamc@183 113 if n1 = n2 then
adamc@258 114 Yes env
adamc@183 115 else
adamc@258 116 No
adamc@183 117
adamc@188 118 | (PCon (_, PConVar n1, SOME p), ECon (_, PConVar n2, SOME e)) =>
adamc@183 119 if n1 = n2 then
adamc@183 120 match (env, p, e)
adamc@183 121 else
adamc@258 122 No
adamc@183 123
adamc@188 124 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, NONE), ECon (_, PConFfi {mod = m2, con = con2, ...}, NONE)) =>
adamc@185 125 if m1 = m2 andalso con1 = con2 then
adamc@258 126 Yes env
adamc@185 127 else
adamc@258 128 No
adamc@185 129
adamc@188 130 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, SOME ep), ECon (_, PConFfi {mod = m2, con = con2, ...}, SOME e)) =>
adamc@185 131 if m1 = m2 andalso con1 = con2 then
adamc@185 132 match (env, p, e)
adamc@185 133 else
adamc@258 134 No
adamc@185 135
adamc@183 136 | (PRecord xps, ERecord xes) =>
adamc@183 137 let
adamc@183 138 fun consider (xps, env) =
adamc@183 139 case xps of
adamc@258 140 [] => Yes env
adamc@183 141 | (x, p, _) :: rest =>
adamc@183 142 case List.find (fn (x', _, _) => x' = x) xes of
adamc@258 143 NONE => No
adamc@183 144 | SOME (_, e, _) =>
adamc@183 145 case match (env, p, e) of
adamc@258 146 No => No
adamc@258 147 | Maybe => Maybe
adamc@258 148 | Yes env => consider (rest, env)
adamc@183 149 in
adamc@183 150 consider (xps, env)
adamc@183 151 end
adamc@183 152
adamc@258 153 | _ => Maybe
adamc@183 154
adamc@133 155 fun exp env e =
adamc@133 156 case e of
adamc@183 157 ERel n =>
adamc@183 158 (case E.lookupERel env n of
adamc@183 159 (_, _, SOME e') => #1 e'
adamc@183 160 | _ => e)
adamc@183 161 | ENamed n =>
adamc@133 162 (case E.lookupENamed env n of
adamc@133 163 (_, _, SOME e', _) => #1 e'
adamc@133 164 | _ => e)
adamc@133 165
adamc@252 166 | EApp ((EAbs (x, t, _, e1), loc), e2) =>
adamc@252 167 ((*Print.prefaces "Considering" [("e1", MonoPrint.p_exp env e1),
adamc@252 168 ("e2", MonoPrint.p_exp env e2)];*)
adamc@252 169 if impure e2 then
adamc@252 170 #1 (reduceExp env (ELet (x, t, e2, e1), loc))
adamc@252 171 else
adamc@252 172 #1 (reduceExp env (subExpInExp (0, e2) e1)))
adamc@133 173
adamc@184 174 | ECase (disc, pes, _) =>
adamc@258 175 let
adamc@258 176 fun search pes =
adamc@258 177 case pes of
adamc@258 178 [] => e
adamc@258 179 | (p, body) :: pes =>
adamc@258 180 case match (env, p, disc) of
adamc@258 181 No => search pes
adamc@258 182 | Maybe => e
adamc@258 183 | Yes env => #1 (reduceExp env body)
adamc@258 184 in
adamc@258 185 search pes
adamc@258 186 end
adamc@183 187
adamc@252 188 | EField ((ERecord xes, _), x) =>
adamc@252 189 (case List.find (fn (x', _, _) => x' = x) xes of
adamc@252 190 SOME (_, e, _) => #1 e
adamc@252 191 | NONE => e)
adamc@252 192
adamc@252 193 | ELet (x1, t1, (ELet (x2, t2, e1, b1), loc), b2) =>
adamc@252 194 let
adamc@252 195 val e' = (ELet (x2, t2, e1,
adamc@252 196 (ELet (x1, t1, b1,
adamc@252 197 liftExpInExp 1 b2), loc)), loc)
adamc@252 198 in
adamc@253 199 (*Print.prefaces "ELet commute" [("e", MonoPrint.p_exp env (e, loc)),
adamc@253 200 ("e'", MonoPrint.p_exp env e')];*)
adamc@252 201 #1 (reduceExp env e')
adamc@252 202 end
adamc@252 203 | EApp ((ELet (x, t, e, b), loc), e') =>
adamc@252 204 #1 (reduceExp env (ELet (x, t, e,
adamc@252 205 (EApp (b, liftExpInExp 0 e'), loc)), loc))
adamc@252 206 | ELet (x, t, e', b) =>
adamc@252 207 if impure e' then
adamc@252 208 e
adamc@252 209 else
adamc@252 210 #1 (reduceExp env (subExpInExp (0, e') b))
adamc@252 211
adamc@268 212 | EStrcat ((EPrim (Prim.String s1), _), (EPrim (Prim.String s2), _)) =>
adamc@268 213 EPrim (Prim.String (s1 ^ s2))
adamc@268 214
adamc@133 215 | _ => e
adamc@133 216
adamc@252 217 and bind (env, b) =
adamc@252 218 case b of
adamc@252 219 U.Decl.Datatype (x, n, xncs) => E.pushDatatype env x n xncs
adamc@252 220 | U.Decl.RelE (x, t) => E.pushERel env x t NONE
adamc@252 221 | U.Decl.NamedE (x, n, t, eo, s) => E.pushENamed env x n t (Option.map (reduceExp env) eo) s
adamc@252 222
adamc@133 223 and reduceExp env = U.Exp.mapB {typ = typ, exp = exp, bind = bind} env
adamc@133 224
adamc@133 225 fun decl env d = d
adamc@133 226
adamc@133 227 val reduce = U.File.mapB {typ = typ, exp = exp, decl = decl, bind = bind} E.empty
adamc@133 228
adamc@133 229 end