## lustrec / src / optimize_machine.ml @ ba2f9fa1

History | View | Annotate | Download (10.9 KB)

1 | b38ffff3 | ploc | (********************************************************************) |
---|---|---|---|

2 | (* *) |
||

3 | (* The LustreC compiler toolset / The LustreC Development Team *) |
||

4 | (* Copyright 2012 - -- ONERA - CNRS - INPT *) |
||

5 | (* *) |
||

6 | (* LustreC is free software, distributed WITHOUT ANY WARRANTY *) |
||

7 | (* under the terms of the GNU Lesser General Public License *) |
||

8 | (* version 2.1. *) |
||

9 | (* *) |
||

10 | (********************************************************************) |
||

11 | |||

12 | 307aba8d | xthirioux | open Utils |

13 | 3ab9437b | ploc | open LustreSpec |

14 | open Corelang |
||

15 | 6aeb3388 | xthirioux | open Causality |

16 | 3ab9437b | ploc | open Machine_code |

17 | |||

18 | 307aba8d | xthirioux | let pp_elim fmt elim = |

19 | begin |
||

20 | Format.fprintf fmt "{ /* elim table: */@."; |
||

21 | IMap.iter (fun v expr -> Format.fprintf fmt "%s |-> %a@." v pp_val expr) elim; |
||

22 | Format.fprintf fmt "}@."; |
||

23 | end |
||

24 | |||

25 | 3ab9437b | ploc | let rec eliminate elim instr = |

26 | let e_expr = eliminate_expr elim in |
||

27 | match instr with |
||

28 | | MLocalAssign (i,v) -> MLocalAssign (i, e_expr v) |
||

29 | | MStateAssign (i,v) -> MStateAssign (i, e_expr v) |
||

30 | | MReset i -> instr |
||

31 | | MStep (il, i, vl) -> MStep(il, i, List.map e_expr vl) |
||

32 | | MBranch (g,hl) -> |
||

33 | MBranch |
||

34 | (e_expr g, |
||

35 | (List.map |
||

36 | (fun (l, il) -> l, List.map (eliminate elim) il) |
||

37 | hl |
||

38 | ) |
||

39 | ) |
||

40 | |||

41 | and eliminate_expr elim expr = |
||

42 | match expr with |
||

43 | 307aba8d | xthirioux | | LocalVar v -> (try IMap.find v.var_id elim with Not_found -> expr) |

44 | 3ab9437b | ploc | | Fun (id, vl) -> Fun (id, List.map (eliminate_expr elim) vl) |

45 | | Array(vl) -> Array(List.map (eliminate_expr elim) vl) |
||

46 | | Access(v1, v2) -> Access(eliminate_expr elim v1, eliminate_expr elim v2) |
||

47 | 307aba8d | xthirioux | | Power(v1, v2) -> Power(eliminate_expr elim v1, eliminate_expr elim v2) |

48 | 3ab9437b | ploc | | Cst _ | StateVar _ -> expr |

49 | |||

50 | 307aba8d | xthirioux | let is_scalar_const c = |

51 | match c with |
||

52 | | Const_int _ |
||

53 | | Const_real _ |
||

54 | | Const_float _ |
||

55 | | Const_tag _ -> true |
||

56 | | _ -> false |
||

57 | |||

58 | let unfoldable_assign fanin v expr = |
||

59 | try |
||

60 | let d = Hashtbl.find fanin v.var_id |
||

61 | in match expr with |
||

62 | | Cst c when is_scalar_const c -> true |
||

63 | | Cst c when d < 2 -> true |
||

64 | | LocalVar _ |
||

65 | | StateVar _ -> true |
||

66 | | Fun (id, _) when d < 2 && Basic_library.is_internal_fun id -> true |
||

67 | | _ -> false |
||

68 | with Not_found -> false |
||

69 | |||

70 | let merge_elim elim1 elim2 = |
||

71 | let merge k e1 e2 = |
||

72 | match e1, e2 with |
||

73 | | Some e1, Some e2 -> if e1 = e2 then Some e1 else None |
||

74 | | _ , Some e2 -> Some e2 |
||

75 | | Some e1, _ -> Some e1 |
||

76 | | _ -> None |
||

77 | in IMap.merge merge elim1 elim2 |
||

78 | |||

79 | 3ab9437b | ploc | (* see if elim has to take in account the provided instr: |

80 | 6a1a01d2 | xthirioux | if so, update elim and return the remove flag, |

81 | 3ab9437b | ploc | otherwise, the expression should be kept and elim is left untouched *) |

82 | 307aba8d | xthirioux | let rec instrs_unfold fanin elim instrs = |

83 | let elim, rev_instrs = |
||

84 | List.fold_left (fun (elim, instrs) instr -> |
||

85 | (* each subexpression in instr that could be rewritten by the elim set is |
||

86 | rewritten *) |
||

87 | let instr = eliminate elim instr in |
||

88 | (* if instr is a simple local assign, then (a) elim is simplified with it (b) it |
||

89 | is stored as the elim set *) |
||

90 | instr_unfold fanin instrs elim instr |
||

91 | ) (elim, []) instrs |
||

92 | in elim, List.rev rev_instrs |
||

93 | |||

94 | and instr_unfold fanin instrs elim instr = |
||

95 | 7a6b5deb | ploc | (* Format.eprintf "SHOULD WE STORE THE EXPRESSION IN INSTR %a TO ELIMINATE IT@." pp_instr instr;*) |

96 | 3ab9437b | ploc | match instr with |

97 | (* Simple cases*) |
||

98 | 307aba8d | xthirioux | | MStep([v], id, vl) when Basic_library.is_internal_fun id |

99 | -> instr_unfold fanin instrs elim (MLocalAssign (v, Fun (id, vl))) |
||

100 | | MLocalAssign(v, expr) when unfoldable_assign fanin v expr |
||

101 | -> (IMap.add v.var_id expr elim, instrs) |
||

102 | | MBranch(g, hl) when false |
||

103 | -> let elim_branches = List.map (fun (h, l) -> (h, instrs_unfold fanin elim l)) hl in |
||

104 | let (elim, branches) = |
||

105 | List.fold_right |
||

106 | (fun (h, (e, l)) (elim, branches) -> (merge_elim elim e, (h, l)::branches)) |
||

107 | elim_branches (elim, []) |
||

108 | in elim, (MBranch (g, branches) :: instrs) |
||

109 | | _ |
||

110 | -> (elim, instr :: instrs) |
||

111 | 3ab9437b | ploc | (* default case, we keep the instruction and do not modify elim *) |

112 | |||

113 | |||

114 | (** We iterate in the order, recording simple local assigns in an accumulator |
||

115 | 1. each expression is rewritten according to the accumulator |
||

116 | 2. local assigns then rewrite occurrences of the lhs in the computed accumulator |
||

117 | *) |
||

118 | |||

119 | (** Perform optimization on machine code: |
||

120 | - iterate through step instructions and remove simple local assigns |
||

121 | |||

122 | *) |
||

123 | 307aba8d | xthirioux | let machine_unfold fanin elim machine = |

124 | (*Log.report ~level:1 (fun fmt -> Format.fprintf fmt "machine_unfold %a@." pp_elim elim);*) |
||

125 | let eliminated_vars, new_instrs = instrs_unfold fanin elim machine.mstep.step_instrs in |
||

126 | let new_locals = List.filter (fun v -> not (IMap.mem v.var_id eliminated_vars)) machine.mstep.step_locals |
||

127 | 3ab9437b | ploc | in |

128 | { |
||

129 | machine with |
||

130 | mstep = { |
||

131 | machine.mstep with |
||

132 | step_locals = new_locals; |
||

133 | step_instrs = new_instrs |
||

134 | } |
||

135 | } |
||

136 | |||

137 | 307aba8d | xthirioux | let instr_of_const top_const = |

138 | let const = const_of_top top_const in |
||

139 | let vdecl = mkvar_decl Location.dummy_loc (const.const_id, mktyp Location.dummy_loc Tydec_any, mkclock Location.dummy_loc Ckdec_any, true) in |
||

140 | let vdecl = { vdecl with var_type = const.const_type } |
||

141 | in MLocalAssign (vdecl, Cst const.const_value) |
||

142 | 3ab9437b | ploc | |

143 | 307aba8d | xthirioux | let machines_unfold consts node_schs machines = |

144 | List.map |
||

145 | (fun m -> |
||

146 | let fanin = (IMap.find m.mname.node_id node_schs).Scheduling.fanin_table in |
||

147 | let elim_consts, _ = instrs_unfold fanin IMap.empty (List.map instr_of_const consts) |
||

148 | in machine_unfold fanin elim_consts m) |
||

149 | machines |
||

150 | 3ab9437b | ploc | |

151 | 01f1a1f4 | xthirioux | (* variable substitution for optimizing purposes *) |

152 | |||

153 | (* checks whether an [instr] is skip and can be removed from program *) |
||

154 | let rec instr_is_skip instr = |
||

155 | match instr with |
||

156 | | MLocalAssign (i, LocalVar v) when i = v -> true |
||

157 | | MStateAssign (i, StateVar v) when i = v -> true |
||

158 | | MBranch (g, hl) -> List.for_all (fun (_, il) -> instrs_are_skip il) hl |
||

159 | | _ -> false |
||

160 | and instrs_are_skip instrs = |
||

161 | List.for_all instr_is_skip instrs |
||

162 | |||

163 | let instr_cons instr cont = |
||

164 | if instr_is_skip instr then cont else instr::cont |
||

165 | |||

166 | let rec instr_remove_skip instr cont = |
||

167 | match instr with |
||

168 | | MLocalAssign (i, LocalVar v) when i = v -> cont |
||

169 | | MStateAssign (i, StateVar v) when i = v -> cont |
||

170 | | MBranch (g, hl) -> MBranch (g, List.map (fun (h, il) -> (h, instrs_remove_skip il [])) hl) :: cont |
||

171 | | _ -> instr::cont |
||

172 | |||

173 | and instrs_remove_skip instrs cont = |
||

174 | List.fold_right instr_remove_skip instrs cont |
||

175 | |||

176 | let rec value_replace_var fvar value = |
||

177 | match value with |
||

178 | | Cst c -> value |
||

179 | | LocalVar v -> LocalVar (fvar v) |
||

180 | | StateVar v -> value |
||

181 | | Fun (id, args) -> Fun (id, List.map (value_replace_var fvar) args) |
||

182 | | Array vl -> Array (List.map (value_replace_var fvar) vl) |
||

183 | | Access (t, i) -> Access(value_replace_var fvar t, i) |
||

184 | | Power (v, n) -> Power(value_replace_var fvar v, n) |
||

185 | |||

186 | let rec instr_replace_var fvar instr cont = |
||

187 | match instr with |
||

188 | | MLocalAssign (i, v) -> instr_cons (MLocalAssign (fvar i, value_replace_var fvar v)) cont |
||

189 | | MStateAssign (i, v) -> instr_cons (MStateAssign (i, value_replace_var fvar v)) cont |
||

190 | | MReset i -> instr_cons instr cont |
||

191 | | MStep (il, i, vl) -> instr_cons (MStep (List.map fvar il, i, List.map (value_replace_var fvar) vl)) cont |
||

192 | | MBranch (g, hl) -> instr_cons (MBranch (value_replace_var fvar g, List.map (fun (h, il) -> (h, instrs_replace_var fvar il [])) hl)) cont |
||

193 | |||

194 | and instrs_replace_var fvar instrs cont = |
||

195 | List.fold_right (instr_replace_var fvar) instrs cont |
||

196 | |||

197 | let step_replace_var fvar step = |
||

198 | (* Some outputs may have been replaced by locals. |
||

199 | We then need to rename those outputs |
||

200 | without changing their clocks, etc *) |
||

201 | let outputs' = |
||

202 | List.map (fun o -> { o with var_id = (fvar o).var_id }) step.step_outputs in |
||

203 | let locals' = |
||

204 | List.fold_left (fun res l -> |
||

205 | let l' = fvar l in |
||

206 | if List.exists (fun o -> o.var_id = l'.var_id) outputs' |
||

207 | then res |
||

208 | else Utils.add_cons l' res) |
||

209 | [] step.step_locals in |
||

210 | { step with |
||

211 | step_checks = List.map (fun (l, v) -> (l, value_replace_var fvar v)) step.step_checks; |
||

212 | step_outputs = outputs'; |
||

213 | step_locals = locals'; |
||

214 | step_instrs = instrs_replace_var fvar step.step_instrs []; |
||

215 | } |
||

216 | |||

217 | let rec machine_replace_variables fvar m = |
||

218 | { m with |
||

219 | mstep = step_replace_var fvar m.mstep |
||

220 | } |
||

221 | |||

222 | let machine_reuse_variables m reuse = |
||

223 | let fvar v = |
||

224 | try |
||

225 | Hashtbl.find reuse v.var_id |
||

226 | with Not_found -> v in |
||

227 | machine_replace_variables fvar m |
||

228 | |||

229 | let machines_reuse_variables prog node_schs = |
||

230 | List.map |
||

231 | (fun m -> |
||

232 | machine_reuse_variables m (Utils.IMap.find m.mname.node_id node_schs).Scheduling.reuse_table |
||

233 | ) prog |
||

234 | |||

235 | 6aeb3388 | xthirioux | let rec instr_assign res instr = |

236 | match instr with |
||

237 | | MLocalAssign (i, _) -> Disjunction.CISet.add i res |
||

238 | | MStateAssign (i, _) -> Disjunction.CISet.add i res |
||

239 | | MBranch (g, hl) -> List.fold_left (fun res (h, b) -> instrs_assign res b) res hl |
||

240 | | MStep (il, _, _) -> List.fold_right Disjunction.CISet.add il res |
||

241 | | _ -> res |
||

242 | |||

243 | and instrs_assign res instrs = |
||

244 | List.fold_left instr_assign res instrs |
||

245 | |||

246 | let rec instr_constant_assign var instr = |
||

247 | match instr with |
||

248 | | MLocalAssign (i, Cst (Const_tag _)) |
||

249 | | MStateAssign (i, Cst (Const_tag _)) -> i = var |
||

250 | | MBranch (g, hl) -> List.for_all (fun (h, b) -> instrs_constant_assign var b) hl |
||

251 | | _ -> false |
||

252 | |||

253 | and instrs_constant_assign var instrs = |
||

254 | List.fold_left (fun res i -> if Disjunction.CISet.mem var (instr_assign Disjunction.CISet.empty i) then instr_constant_assign var i else res) false instrs |
||

255 | |||

256 | let rec instr_reduce branches instr1 cont = |
||

257 | match instr1 with |
||

258 | | MLocalAssign (_, Cst (Const_tag c)) -> instr1 :: (List.assoc c branches @ cont) |
||

259 | | MStateAssign (_, Cst (Const_tag c)) -> instr1 :: (List.assoc c branches @ cont) |
||

260 | | MBranch (g, hl) -> MBranch (g, List.map (fun (h, b) -> (h, instrs_reduce branches b [])) hl) :: cont |
||

261 | | _ -> instr1 :: cont |
||

262 | |||

263 | and instrs_reduce branches instrs cont = |
||

264 | match instrs with |
||

265 | | [] -> cont |
||

266 | | [i] -> instr_reduce branches i cont |
||

267 | | i1::i2::q -> i1 :: instrs_reduce branches (i2::q) cont |
||

268 | |||

269 | let rec instrs_fusion instrs = |
||

270 | match instrs with |
||

271 | | [] |
||

272 | | [_] -> |
||

273 | instrs |
||

274 | | i1::(MBranch (LocalVar v, hl))::q when instr_constant_assign v i1 -> |
||

275 | instr_reduce (List.map (fun (h, b) -> h, instrs_fusion b) hl) i1 (instrs_fusion q) |
||

276 | | i1::(MBranch (StateVar v, hl))::q when instr_constant_assign v i1 -> |
||

277 | instr_reduce (List.map (fun (h, b) -> h, instrs_fusion b) hl) i1 (instrs_fusion q) |
||

278 | | i1::i2::q -> |
||

279 | i1 :: instrs_fusion (i2::q) |
||

280 | |||

281 | let step_fusion step = |
||

282 | { step with |
||

283 | step_instrs = instrs_fusion step.step_instrs; |
||

284 | } |
||

285 | |||

286 | let rec machine_fusion m = |
||

287 | { m with |
||

288 | mstep = step_fusion m.mstep |
||

289 | } |
||

290 | |||

291 | let machines_fusion prog = |
||

292 | List.map machine_fusion prog |
||

293 | 3ab9437b | ploc | |

294 | (* Local Variables: *) |
||

295 | (* compile-command:"make -C .." *) |
||

296 | (* End: *) |