## lustrec / src / scheduling.ml @ 5f3d7be6

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1 | a2d97a3e | ploc | (********************************************************************) |
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2 | (* *) |
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3 | (* The LustreC compiler toolset / The LustreC Development Team *) |
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4 | (* Copyright 2012 - -- ONERA - CNRS - INPT *) |
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5 | (* *) |
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6 | (* LustreC is free software, distributed WITHOUT ANY WARRANTY *) |
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7 | (* under the terms of the GNU Lesser General Public License *) |
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8 | (* version 2.1. *) |
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9 | (* *) |
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10 | (********************************************************************) |
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11 | 22fe1c93 | ploc | |

12 | open Utils |
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13 | 8446bf03 | ploc | open Lustre_types |

14 | 22fe1c93 | ploc | open Corelang |

15 | open Graph |
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16 | open Causality |
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17 | |||

18 | 3bfed7f9 | xthirioux | type schedule_report = |

19 | { |
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20 | 04a63d25 | xthirioux | (* the scheduled node *) |

21 | node : node_desc; |
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22 | 8a183477 | xthirioux | (* a schedule computed wrt the dependency graph *) |

23 | a38c681e | xthirioux | schedule : ident list list; |

24 | 8a183477 | xthirioux | (* the set of unused variables (no output or mem depends on them) *) |

25 | 3bfed7f9 | xthirioux | unused_vars : ISet.t; |

26 | 8a183477 | xthirioux | (* the table mapping each local var to its in-degree *) |

27 | fanin_table : (ident, int) Hashtbl.t; |
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28 | 04a63d25 | xthirioux | (* the dependency graph *) |

29 | dep_graph : IdentDepGraph.t; |
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30 | bb2ca5f4 | xthirioux | (* the table mapping each assignment to a reusable variable *) |

31 | 04a63d25 | xthirioux | (*reuse_table : (ident, var_decl) Hashtbl.t*) |

32 | 3bfed7f9 | xthirioux | } |

33 | 22fe1c93 | ploc | |

34 | (* Topological sort with a priority for variables belonging in the same equation lhs. |
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35 | For variables still unrelated, standard compare is used to choose the minimal element. |
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36 | This priority is used since it helps a lot in factorizing generated code. |
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37 | b1655a21 | xthirioux | Moreover, the dependency graph is browsed in a depth-first manner whenever possible, |

38 | to improve the behavior of optimization algorithms applied in forthcoming compilation steps. |
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39 | 22fe1c93 | ploc | In the following functions: |

40 | - [eq_equiv] is the equivalence relation between vars of the same equation lhs |
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41 | - [g] the (imperative) graph to be topologically sorted |
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42 | - [pending] is the set of unsorted root variables so far, equivalent to the last sorted var |
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43 | - [frontier] is the set of unsorted root variables so far, not belonging in [pending] |
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44 | - [sort] is the resulting topological order |
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45 | *) |
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46 | a38c681e | xthirioux | |

47 | (* Checks whether the currently scheduled variable [choice] |
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48 | is an output of a call, possibly among others *) |
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49 | let is_call_output choice g = |
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50 | 04d15b97 | xthirioux | List.exists ExprDep.is_instance_var (IdentDepGraph.succ g choice) |

51 | a38c681e | xthirioux | |

52 | 22fe1c93 | ploc | (* Adds successors of [v] in graph [g] in [pending] or [frontier] sets, wrt [eq_equiv], |

53 | then removes [v] from [g] |
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54 | *) |
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55 | let add_successors eq_equiv g v pending frontier = |
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56 | let succs_v = IdentDepGraph.succ g v in |
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57 | begin |
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58 | IdentDepGraph.remove_vertex g v; |
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59 | b84a138e | ploc | List.iter |

60 | (fun v' -> |
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61 | if is_graph_root v' g then |
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62 | (if eq_equiv v v' then |
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63 | pending := ISet.add v' !pending |
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64 | else |
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65 | frontier := ISet.add v' !frontier) |
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66 | ) succs_v; |
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67 | 22fe1c93 | ploc | end |

68 | |||

69 | (* Chooses the next var to be sorted, taking priority into account. |
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70 | Modifies [pending] and [frontier] accordingly. |
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71 | *) |
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72 | a38c681e | xthirioux | let next_element eq_equiv g sort call pending frontier = |

73 | 8ea13d96 | xthirioux | begin |

74 | if ISet.is_empty !pending |
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75 | then |
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76 | begin |
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77 | let choice = ISet.min_elt !frontier in |
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78 | 22fe1c93 | ploc | (*Format.eprintf "-1-> %s@." choice;*) |

79 | 8ea13d96 | xthirioux | frontier := ISet.remove choice !frontier; |

80 | let (p, f) = ISet.partition (eq_equiv choice) !frontier in |
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81 | pending := p; |
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82 | frontier := f; |
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83 | a38c681e | xthirioux | call := is_call_output choice g; |

84 | 8ea13d96 | xthirioux | add_successors eq_equiv g choice pending frontier; |

85 | a38c681e | xthirioux | if not (ExprDep.is_ghost_var choice) |

86 | then sort := [choice] :: !sort |
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87 | 8ea13d96 | xthirioux | end |

88 | else |
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89 | begin |
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90 | let choice = ISet.min_elt !pending in |
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91 | 22fe1c93 | ploc | (*Format.eprintf "-2-> %s@." choice;*) |

92 | 8ea13d96 | xthirioux | pending := ISet.remove choice !pending; |

93 | add_successors eq_equiv g choice pending frontier; |
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94 | a38c681e | xthirioux | if not (ExprDep.is_ghost_var choice) |

95 | then sort := (if !call |
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96 | then (choice :: List.hd !sort) :: List.tl !sort |
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97 | else [choice] :: !sort) |
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98 | 8ea13d96 | xthirioux | end |

99 | end |
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100 | |||

101 | 22fe1c93 | ploc | |

102 | (* Topological sort of dependency graph [g], with priority. |
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103 | *) |
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104 | let topological_sort eq_equiv g = |
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105 | let roots = graph_roots g in |
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106 | assert (roots <> []); |
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107 | a38c681e | xthirioux | let call = ref false in |

108 | 22fe1c93 | ploc | let frontier = ref (List.fold_right ISet.add roots ISet.empty) in |

109 | let pending = ref ISet.empty in |
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110 | let sorted = ref [] in |
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111 | begin |
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112 | while not (ISet.is_empty !frontier && ISet.is_empty !pending) |
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113 | do |
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114 | (*Format.eprintf "frontier = {%a}, pending = {%a}@." |
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115 | (fun fmt -> ISet.iter (fun e -> Format.pp_print_string fmt e)) !frontier |
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116 | (fun fmt -> ISet.iter (fun e -> Format.pp_print_string fmt e)) !pending;*) |
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117 | a38c681e | xthirioux | next_element eq_equiv g sorted call pending frontier; |

118 | 22fe1c93 | ploc | done; |

119 | 8ea13d96 | xthirioux | IdentDepGraph.clear g; |

120 | 22fe1c93 | ploc | !sorted |

121 | end |
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122 | |||

123 | 54d032f5 | xthirioux | (* Filters out normalization variables and renames instance variables to keep things readable, |

124 | in a case of a dependency error *) |
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125 | let filter_original n vl = |
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126 | List.fold_right (fun v res -> |
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127 | if ExprDep.is_instance_var v then Format.sprintf "node %s" (ExprDep.undo_instance_var v) :: res else |
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128 | let vdecl = get_node_var v n in |
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129 | if vdecl.var_orig then v :: res else res) vl [] |
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130 | |||

131 | 7afcba5a | xthirioux | let schedule_node n = |

132 | 04a63d25 | xthirioux | (* let node_vars = get_node_vars n in *) |

133 | e7cc5186 | ploc | let eq_equiv = ExprDep.node_eq_equiv n in |

134 | let eq_equiv v1 v2 = |
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135 | try |
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136 | Hashtbl.find eq_equiv v1 = Hashtbl.find eq_equiv v2 |
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137 | with Not_found -> false in |
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138 | cd670fe1 | ploc | |

139 | e7cc5186 | ploc | let n', g = global_dependency n in |

140 | |||

141 | (* TODO X: extend the graph with inputs (adapt the causality analysis to deal with inputs |
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142 | 0e1049dc | xthirioux | compute: coi predecessors of outputs |

143 | warning (no modification) when memories are non used (do not impact output) or when inputs are not used (do not impact output) |
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144 | e7cc5186 | ploc | DONE ! |

145 | *) |
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146 | 0e1049dc | xthirioux | |

147 | e7cc5186 | ploc | let gg = IdentDepGraph.copy g in |

148 | let sort = topological_sort eq_equiv g in |
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149 | let unused = Liveness.compute_unused_variables n gg in |
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150 | let fanin = Liveness.compute_fanin n gg in |
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151 | { node = n'; schedule = sort; unused_vars = unused; fanin_table = fanin; dep_graph = gg; } |
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152 | ec433d69 | xthirioux | |

153 | b1a97ade | xthirioux | |

154 | 04a63d25 | xthirioux | let compute_node_reuse_table report = |

155 | let disjoint = Disjunction.clock_disjoint_map (get_node_vars report.node) in |
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156 | let reuse = Liveness.compute_reuse_policy report.node report.schedule disjoint report.dep_graph in |
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157 | (* |
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158 | 89a70069 | xthirioux | if !Options.print_reuse |

159 | then |
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160 | begin |
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161 | Log.report ~level:0 |
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162 | (fun fmt -> |
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163 | Format.fprintf fmt |
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164 | 790765c0 | xthirioux | "OPT:%B@." (try (Hashtbl.iter (fun s1 v2 -> if s1 = v2.var_id then raise Not_found) reuse; false) with Not_found -> true) |

165 | ); |
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166 | Log.report ~level:0 |
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167 | (fun fmt -> |
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168 | Format.fprintf fmt |
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169 | 89a70069 | xthirioux | "OPT:clock disjoint map for node %s: %a" |

170 | n'.node_id |
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171 | Disjunction.pp_disjoint_map disjoint |
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172 | ); |
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173 | Log.report ~level:0 |
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174 | (fun fmt -> |
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175 | Format.fprintf fmt |
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176 | "OPT:reuse policy for node %s: %a" |
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177 | n'.node_id |
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178 | Liveness.pp_reuse_policy reuse |
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179 | ); |
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180 | end; |
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181 | 04a63d25 | xthirioux | *) |

182 | reuse |
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183 | |||

184 | 22fe1c93 | ploc | |

185 | 88486aaf | ploc | let schedule_prog prog = |

186 | List.fold_right ( |
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187 | 3bfed7f9 | xthirioux | fun top_decl (accu_prog, sch_map) -> |

188 | 88486aaf | ploc | match top_decl.top_decl_desc with |

189 | f4050bef | ploc | | Node nd -> |

190 | let report = schedule_node nd in |
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191 | {top_decl with top_decl_desc = Node report.node}::accu_prog, |
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192 | IMap.add nd.node_id report sch_map |
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193 | 3bfed7f9 | xthirioux | | _ -> top_decl::accu_prog, sch_map |

194 | 88486aaf | ploc | ) |

195 | prog |
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196 | 3bfed7f9 | xthirioux | ([],IMap.empty) |

197 | 04a63d25 | xthirioux | |

198 | |||

199 | let compute_prog_reuse_table report = |
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200 | IMap.map compute_node_reuse_table report |
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201 | |||

202 | (* removes inlined local variables from schedule report, |
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203 | which are now useless *) |
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204 | let remove_node_inlined_locals locals report = |
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205 | let is_inlined v = IMap.exists (fun l _ -> v = l) locals in |
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206 | let schedule' = |
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207 | List.fold_right (fun heads q -> let heads' = List.filter (fun v -> not (is_inlined v)) heads |
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208 | in if heads' = [] then q else heads'::q) |
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209 | report.schedule [] in |
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210 | begin |
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211 | IMap.iter (fun v _ -> Hashtbl.remove report.fanin_table v) locals; |
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212 | IMap.iter (fun v _ -> let iv = ExprDep.mk_instance_var v |
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213 | in Liveness.replace_in_dep_graph v iv report.dep_graph) locals; |
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214 | { report with schedule = schedule' } |
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215 | end |
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216 | |||

217 | let remove_prog_inlined_locals removed reuse = |
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218 | IMap.mapi (fun id -> remove_node_inlined_locals (IMap.find id removed)) reuse |
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219 | 3bfed7f9 | xthirioux | |

220 | a38c681e | xthirioux | let pp_eq_schedule fmt vl = |

221 | match vl with |
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222 | | [] -> assert false |
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223 | | [v] -> Format.fprintf fmt "%s" v |
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224 | | _ -> Format.fprintf fmt "(%a)" (fprintf_list ~sep:" , " (fun fmt v -> Format.fprintf fmt "%s" v)) vl |
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225 | |||

226 | 8a183477 | xthirioux | let pp_schedule fmt node_schs = |

227 | IMap.iter |
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228 | (fun nd report -> |
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229 | Format.fprintf fmt "%s schedule: %a@." |
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230 | nd |
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231 | a38c681e | xthirioux | (fprintf_list ~sep:" ; " pp_eq_schedule) report.schedule) |

232 | 8a183477 | xthirioux | node_schs |

233 | |||

234 | let pp_fanin_table fmt node_schs = |
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235 | IMap.iter |
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236 | (fun nd report -> |
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237 | 04a63d25 | xthirioux | Format.fprintf fmt "%s: %a" nd Liveness.pp_fanin report.fanin_table) |

238 | node_schs |
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239 | |||

240 | let pp_dep_graph fmt node_schs = |
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241 | IMap.iter |
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242 | (fun nd report -> |
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243 | Format.fprintf fmt "%s dependency graph: %a" nd pp_dep_graph report.dep_graph) |
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244 | 8a183477 | xthirioux | node_schs |

245 | |||

246 | 3bfed7f9 | xthirioux | let pp_warning_unused fmt node_schs = |

247 | IMap.iter |
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248 | (fun nd report -> |
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249 | let unused = report.unused_vars in |
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250 | if not (ISet.is_empty unused) |
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251 | then |
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252 | let nd = match (Corelang.node_from_name nd).top_decl_desc with Node nd -> nd | _ -> assert false in |
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253 | ISet.iter |
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254 | df39e35a | xthirioux | (fun u -> |

255 | let vu = get_node_var u nd in |
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256 | if vu.var_orig |
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257 | 04a63d25 | xthirioux | then Format.fprintf fmt " Warning: variable '%s' seems unused@, %a@,@," u Location.pp_loc vu.var_loc) |

258 | 3bfed7f9 | xthirioux | unused |

259 | ) |
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260 | node_schs |
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261 | 22fe1c93 | ploc | |

262 | 04a63d25 | xthirioux | |

263 | 22fe1c93 | ploc | (* Local Variables: *) |

264 | (* compile-command:"make -C .." *) |
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265 | (* End: *) |