adamc@23: (* Copyright (c) 2008, Adam Chlipala
adamc@23:  * All rights reserved.
adamc@23:  *
adamc@23:  * Redistribution and use in source and binary forms, with or without
adamc@23:  * modification, are permitted provided that the following conditions are met:
adamc@23:  *
adamc@23:  * - Redistributions of source code must retain the above copyright notice,
adamc@23:  *   this list of conditions and the following disclaimer.
adamc@23:  * - Redistributions in binary form must reproduce the above copyright notice,
adamc@23:  *   this list of conditions and the following disclaimer in the documentation
adamc@23:  *   and/or other materials provided with the distribution.
adamc@23:  * - The names of contributors may not be used to endorse or promote products
adamc@23:  *   derived from this software without specific prior written permission.
adamc@23:  *
adamc@23:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@23:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@23:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@23:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
adamc@23:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@23:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@23:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@23:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@23:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@23:  * POSSIBILITY OF SUCH DAMAGE.
adamc@23:  *)
adamc@23: 
adamc@23: (* Remove unused definitions from a file *)
adamc@23: 
adamc@23: structure Shake :> SHAKE = struct
adamc@23: 
adamc@23: open Core
adamc@23: 
adamc@23: structure U = CoreUtil
adamc@23: 
adamc@23: structure IS = IntBinarySet
adamc@23: structure IM = IntBinaryMap
adamc@23: 
adamc@23: type free = {
adamc@23:      con : IS.set,
adamc@23:      exp : IS.set
adamc@23: }
adamc@23: 
adamc@23: fun shake file =
adamc@100:     let
adamc@109:         val page_es = List.foldl
adamc@144:                           (fn ((DExport (_, n), _), page_es) => n :: page_es
adamc@109:                             | (_, page_es) => page_es) [] file
adamc@23: 
adamc@163:         val (cdef, edef) = foldl (fn ((DCon (_, n, _, c), _), (cdef, edef)) => (IM.insert (cdef, n, [c]), edef)
adamc@192:                                    | ((DDatatype (_, n, _, xncs), _), (cdef, edef)) =>
adamc@163:                                      (IM.insert (cdef, n, List.mapPartial #3 xncs), edef)
adamc@109:                                    | ((DVal (_, n, t, e, _), _), (cdef, edef)) => (cdef, IM.insert (edef, n, (t, e)))
adamc@125:                                    | ((DValRec vis, _), (cdef, edef)) =>
adamc@125:                                      (cdef, foldl (fn ((_, n, t, e, _), edef) => IM.insert (edef, n, (t, e))) edef vis)
adamc@109:                                    | ((DExport _, _), acc) => acc)
adamc@100:                                  (IM.empty, IM.empty) file
adamc@23: 
adamc@100:         fun kind (_, s) = s
adamc@23: 
adamc@100:         fun con (c, s) =
adamc@100:             case c of
adamc@100:                 CNamed n =>
adamc@100:                 if IS.member (#con s, n) then
adamc@100:                     s
adamc@100:                 else
adamc@100:                     let
adamc@100:                         val s' = {con = IS.add (#con s, n),
adamc@100:                                   exp = #exp s}
adamc@100:                     in
adamc@100:                         case IM.find (cdef, n) of
adamc@100:                             NONE => s'
adamc@163:                           | SOME cs => foldl (fn (c, s') => shakeCon s' c) s' cs
adamc@100:                     end
adamc@100:               | _ => s
adamc@23: 
adamc@100:         and shakeCon s = U.Con.fold {kind = kind, con = con} s
adamc@23: 
adamc@100:         fun exp (e, s) =
adamc@100:             case e of
adamc@100:                 ENamed n =>
adamc@100:                 if IS.member (#exp s, n) then
adamc@100:                     s
adamc@100:                 else
adamc@100:                     let
adamc@100:                         val s' = {exp = IS.add (#exp s, n),
adamc@100:                                   con = #con s}
adamc@100:                     in
adamc@100:                         case IM.find (edef, n) of
adamc@100:                             NONE => s'
adamc@100:                           | SOME (t, e) => shakeExp (shakeCon s' t) e
adamc@100:                     end
adamc@100:               | _ => s
adamc@23: 
adamc@100:         and shakeExp s = U.Exp.fold {kind = kind, con = con, exp = exp} s
adamc@100: 
adamc@109:         val s = {con = IS.empty, exp = IS.addList (IS.empty, page_es)}
adamc@109: 
adamc@109:         val s = foldl (fn (n, s) =>
adamc@109:                           case IM.find (edef, n) of
adamc@109:                               NONE => raise Fail "Shake: Couldn't find 'val'"
adamc@109:                             | SOME (t, e) => shakeExp (shakeCon s t) e) s page_es
adamc@100:     in
adamc@100:         List.filter (fn (DCon (_, n, _, _), _) => IS.member (#con s, n)
adamc@192:                       | (DDatatype (_, n, _, _), _) => IS.member (#con s, n)
adamc@109:                       | (DVal (_, n, _, _, _), _) => IS.member (#exp s, n)
adamc@125:                       | (DValRec vis, _) => List.exists (fn (_, n, _, _, _) => IS.member (#exp s, n)) vis
adamc@109:                       | (DExport _, _) => true) file
adamc@100:     end
adamc@23: 
adamc@23: end