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1 | (* HCoop Domtool (http://hcoop.sourceforge.net/) |
2 | * Copyright (c) 2007, Adam Chlipala | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
17 | *) | |
18 | ||
19 | (* Domtool configuration language unused environment variable setting analysis *) | |
20 | ||
21 | structure Unused :> UNUSED = struct | |
22 | ||
23 | open Ast | |
24 | structure SM = StringMap | |
25 | structure SS = StringSet | |
26 | ||
27 | fun check G e = | |
28 | let | |
29 | fun used vars x = | |
30 | (#1 (SM.remove (vars, x))) | |
31 | handle NotFound => vars | |
32 | ||
33 | fun unused loc x = | |
34 | ErrorMsg.warning (SOME loc) ("Unused setting of environment variable " ^ x) | |
35 | ||
36 | fun writing vars x loc = | |
37 | (Option.app (fn loc' => unused loc' x) (SM.find (vars, x)); | |
38 | SM.insert (vars, x, loc)) | |
39 | ||
40 | fun findHead (e, _) = | |
41 | case e of | |
42 | EVar x => SOME x | |
43 | | EApp (e, _) => findHead e | |
44 | | _ => NONE | |
45 | ||
46 | fun processTy f default loc t = | |
47 | case #1 (Describe.ununify t) of | |
48 | TArrow (_, t) => processTy f default loc t | |
49 | | TNested (_, t) => processTy f default loc t | |
50 | ||
51 | | TAction (_, reads, writes) => f (reads, writes) | |
52 | ||
53 | | _ => default | |
54 | ||
55 | fun writes (e, _) = | |
56 | case e of | |
57 | ESet (x, _) => SS.singleton x | |
58 | | EGet (_, _, _, e) => writes e | |
59 | | ESeq es => foldl (fn (e, s) => SS.union (writes e, s)) SS.empty es | |
60 | | ELocal (_, e) => writes e | |
61 | | EWith (e, _) => writes e | |
62 | | _ => SS.empty | |
63 | ||
64 | fun chk (eAll as (e, loc), vars) = | |
65 | case e of | |
66 | EInt _ => vars | |
67 | | EString _ => vars | |
68 | | EList es => vars | |
69 | | ELam _ => vars | |
70 | | ESkip => vars | |
71 | ||
72 | | ESet (x, _) => writing vars x loc | |
73 | | EGet (_, _, x, e) => chk (e, used vars x) | |
74 | | ESeq es => foldl chk vars es | |
75 | | ELocal (e1, e2) => | |
76 | let | |
77 | val vars = chk (e2, chk (e1, vars)) | |
78 | val writes1 = writes e1 | |
79 | val writes2 = writes e2 | |
80 | in | |
81 | SM.foldli (fn (x, _, vars') => | |
82 | if SS.member (writes1, x) | |
83 | andalso not (SS.member (writes2, x)) then | |
84 | SM.insert (vars', x, valOf (SM.find (vars, x))) | |
85 | else | |
86 | vars') vars vars | |
87 | end | |
88 | | EWith (e1, e2) => chk (e2, chk (e1, vars)) | |
89 | | EALam _ => vars | |
90 | | EIf _ => vars | |
91 | ||
92 | | _ => | |
93 | let | |
94 | val processTy = processTy (fn (reads, writes) => | |
95 | let | |
96 | val vars = SM.foldli (fn (x, _, vars) => used vars x) vars reads | |
97 | in | |
98 | SM.foldli (fn (x, _, vars) => writing vars x loc) vars writes | |
99 | end) | |
100 | vars | |
101 | in | |
102 | case findHead eAll of | |
103 | NONE => raise Fail "Couldn't find the head" | |
104 | | SOME head => | |
105 | case Env.lookupVal G head of | |
106 | NONE => vars | |
107 | | SOME t => processTy loc t | |
108 | end | |
109 | in | |
110 | SM.appi (fn (x, loc) => unused loc x) (chk (e, SM.empty)) | |
111 | end | |
112 | end |