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annotate src/shake.sml @ 23:bfa2e9ae4df8

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Tree-shaking
author Adam Chlipala <adamc@hcoop.net>
date Sun, 08 Jun 2008 17:15:09 -0400
parents
children 02f42e9a1825
rev   line source
adamc@23 1 (* Copyright (c) 2008, Adam Chlipala
adamc@23 2 * All rights reserved.
adamc@23 3 *
adamc@23 4 * Redistribution and use in source and binary forms, with or without
adamc@23 5 * modification, are permitted provided that the following conditions are met:
adamc@23 6 *
adamc@23 7 * - Redistributions of source code must retain the above copyright notice,
adamc@23 8 * this list of conditions and the following disclaimer.
adamc@23 9 * - Redistributions in binary form must reproduce the above copyright notice,
adamc@23 10 * this list of conditions and the following disclaimer in the documentation
adamc@23 11 * and/or other materials provided with the distribution.
adamc@23 12 * - The names of contributors may not be used to endorse or promote products
adamc@23 13 * derived from this software without specific prior written permission.
adamc@23 14 *
adamc@23 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@23 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@23 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@23 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@23 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
adamc@23 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@23 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@23 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@23 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@23 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@23 25 * POSSIBILITY OF SUCH DAMAGE.
adamc@23 26 *)
adamc@23 27
adamc@23 28 (* Remove unused definitions from a file *)
adamc@23 29
adamc@23 30 structure Shake :> SHAKE = struct
adamc@23 31
adamc@23 32 open Core
adamc@23 33
adamc@23 34 structure U = CoreUtil
adamc@23 35
adamc@23 36 structure IS = IntBinarySet
adamc@23 37 structure IM = IntBinaryMap
adamc@23 38
adamc@23 39 type free = {
adamc@23 40 con : IS.set,
adamc@23 41 exp : IS.set
adamc@23 42 }
adamc@23 43
adamc@23 44 fun shake file =
adamc@23 45 case List.foldl (fn ((DVal ("main", n, _, e), _), _) => SOME (n, e)
adamc@23 46 | (_, s) => s) NONE file of
adamc@23 47 NONE => []
adamc@23 48 | SOME (main, body) =>
adamc@23 49 let
adamc@23 50 val (cdef, edef) = foldl (fn ((DCon (_, n, _, c), _), (cdef, edef)) => (IM.insert (cdef, n, c), edef)
adamc@23 51 | ((DVal (_, n, t, e), _), (cdef, edef)) => (cdef, IM.insert (edef, n, (t, e))))
adamc@23 52 (IM.empty, IM.empty) file
adamc@23 53
adamc@23 54 fun kind (_, s) = s
adamc@23 55
adamc@23 56 fun con (c, s) =
adamc@23 57 case c of
adamc@23 58 CNamed n =>
adamc@23 59 if IS.member (#con s, n) then
adamc@23 60 s
adamc@23 61 else
adamc@23 62 let
adamc@23 63 val s' = {con = IS.add (#con s, n),
adamc@23 64 exp = #exp s}
adamc@23 65 in
adamc@23 66 case IM.find (cdef, n) of
adamc@23 67 NONE => s'
adamc@23 68 | SOME c => shakeCon s' c
adamc@23 69 end
adamc@23 70 | _ => s
adamc@23 71
adamc@23 72 and shakeCon s = U.Con.fold {kind = kind, con = con} s
adamc@23 73
adamc@23 74 fun exp (e, s) =
adamc@23 75 case e of
adamc@23 76 ENamed n =>
adamc@23 77 if IS.member (#exp s, n) then
adamc@23 78 s
adamc@23 79 else
adamc@23 80 let
adamc@23 81 val s' = {exp = IS.add (#exp s, n),
adamc@23 82 con = #con s}
adamc@23 83 in
adamc@23 84 case IM.find (edef, n) of
adamc@23 85 NONE => s'
adamc@23 86 | SOME (t, e) => shakeExp (shakeCon s' t) e
adamc@23 87 end
adamc@23 88 | _ => s
adamc@23 89
adamc@23 90 and shakeExp s = U.Exp.fold {kind = kind, con = con, exp = exp} s
adamc@23 91
adamc@23 92 val s = {con = IS.empty,
adamc@23 93 exp = IS.singleton main}
adamc@23 94
adamc@23 95 val s = U.Exp.fold {kind = kind, con = con, exp = exp} s body
adamc@23 96 in
adamc@23 97 List.filter (fn (DCon (_, n, _, _), _) => IS.member (#con s, n)
adamc@23 98 | (DVal (_, n, _, _), _) => IS.member (#exp s, n)) file
adamc@23 99 end
adamc@23 100
adamc@23 101 end