Project

General

Profile

Download (15.9 KB) Statistics
| Branch: | Tag: | Revision:
1
(* ----------------------------------------------------------------------------
2
 * SchedMCore - A MultiCore Scheduling Framework
3
 * Copyright (C) 2009-2011, ONERA, Toulouse, FRANCE - LIFL, Lille, FRANCE
4
 *
5
 * This file is part of Prelude
6
 *
7
 * Prelude is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public License
9
 * as published by the Free Software Foundation ; either version 2 of
10
 * the License, or (at your option) any later version.
11
 *
12
 * Prelude is distributed in the hope that it will be useful, but
13
 * WITHOUT ANY WARRANTY ; without even the implied warranty of
14
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15
 * Lesser General Public License for more details.
16
 *
17
 * You should have received a copy of the GNU Lesser General Public
18
 * License along with this program ; if not, write to the Free Software
19
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
20
 * USA
21
 *---------------------------------------------------------------------------- *)
22

    
23

    
24
(** Simple modular syntactic causality analysis. Can reject correct
25
    programs, especially if the program is not flattened first. *)
26
open Utils
27
open LustreSpec
28
open Corelang
29
open Graph
30
open Format
31

    
32
exception Cycle of ident list
33

    
34
module IdentDepGraph = Graph.Imperative.Digraph.ConcreteBidirectional (IdentModule)
35

    
36
(*module IdentDepGraphUtil = Oper.P(IdentDepGraph)*)
37

    
38
(* Dependency of mem variables on mem variables is cut off 
39
   by duplication of some mem vars into local node vars.
40
   Thus, cylic dependency errors may only arise between no-mem vars.
41
   
42
no_mem' = combinational(no_mem, mem);
43
=> (mem -> no_mem' -> no_mem)
44

    
45
mem' = pre(no_mem, mem);
46
=> (mem' -> no_mem), (mem -> mem')
47

    
48
   Global roadmap:
49
   - compute two dep graphs g (non-mem/non-mem&mem) and g' (mem/mem)
50
   - check cycles in g (a cycle means a dependency error)
51
   - break cycles in g' (it's legal !):
52
     - check cycles in g'
53
     - if any, introduce aux var to break cycle, then start afresh
54
   - insert g' into g
55
   - return g
56
*)
57

    
58
(* Tests whether [v] is a root of graph [g], i.e. a source *)
59
let is_graph_root v g =
60
 IdentDepGraph.in_degree g v = 0
61

    
62
(* Computes the set of graph roots, i.e. the sources of acyclic graph [g] *)
63
let graph_roots g =
64
 IdentDepGraph.fold_vertex
65
   (fun v roots -> if is_graph_root v g then v::roots else roots)
66
   g []
67

    
68
let add_edges src tgt g =
69
(*List.iter (fun s -> List.iter (fun t -> Format.eprintf "add %s -> %s@." s t) tgt) src;*)
70
 List.iter
71
   (fun s ->
72
     List.iter
73
       (fun t -> IdentDepGraph.add_edge g s t)
74
       tgt)
75
   src;
76
  g
77

    
78
let add_vertices vtc g =
79
(*List.iter (fun t -> Format.eprintf "add %s@." t) vtc;*)
80
 List.iter (fun v -> IdentDepGraph.add_vertex g v) vtc;
81
  g
82

    
83
let new_graph () =
84
 IdentDepGraph.create ()
85

    
86
module ExprDep = struct
87

    
88
let eq_var_cpt = ref 0
89

    
90
let instance_var_cpt = ref 0
91

    
92
let mk_eq_var id =
93
 incr eq_var_cpt; sprintf "#%s_%d" id !eq_var_cpt
94

    
95
let mk_instance_var id =
96
 incr instance_var_cpt; sprintf "!%s_%d" id !instance_var_cpt
97

    
98
let is_eq_var v = v.[0] = '#'
99

    
100
let is_instance_var v = v.[0] = '!'
101

    
102
let is_ghost_var v = is_instance_var v || is_eq_var v
103

    
104
let eq_memory_variables mems eq =
105
  let rec match_mem lhs rhs mems =
106
    match rhs.expr_desc with
107
    | Expr_fby _
108
    | Expr_pre _    -> List.fold_right ISet.add lhs mems
109
    | Expr_tuple tl -> 
110
      let lhs' = (transpose_list [lhs]) in
111
      if List.length tl <> List.length lhs' then
112
	assert false;
113
      List.fold_right2 match_mem lhs' tl mems
114
    | _             -> mems in
115
  match_mem eq.eq_lhs eq.eq_rhs mems
116

    
117
let node_memory_variables nd =
118
 List.fold_left eq_memory_variables ISet.empty nd.node_eqs
119

    
120
let node_non_input_variables nd =
121
  let outputs = List.fold_left (fun outputs v -> ISet.add v.var_id outputs) ISet.empty nd.node_outputs in
122
  List.fold_left (fun non_inputs v -> ISet.add v.var_id non_inputs) outputs nd.node_locals
123

    
124
(* computes the equivalence relation relating variables 
125
   in the same equation lhs, under the form of a table 
126
   of class representatives *)
127
let node_eq_equiv nd =
128
  let eq_equiv = Hashtbl.create 23 in
129
  List.iter (fun eq ->
130
    let first = List.hd eq.eq_lhs in
131
    List.iter (fun v -> Hashtbl.add eq_equiv v first) eq.eq_lhs
132
  )
133
    nd.node_eqs;
134
  eq_equiv
135

    
136
(* Create a tuple of right dimension, according to [expr] type, *)
137
(* filled with variable [v] *)
138
let adjust_tuple v expr =
139
 match expr.expr_type.Types.tdesc with
140
 | Types.Ttuple tl -> duplicate v (List.length tl)
141
 | _         -> [v]
142

    
143

    
144
(* Add dependencies from lhs to rhs in [g, g'], *)
145
(* no-mem/no-mem and mem/no-mem in g            *)
146
(* mem/mem in g'                                *)
147
(* excluding all/[inputs]                       *)
148
let add_eq_dependencies mems non_inputs eq (g, g') =
149
  let add_var lhs_is_mem lhs x (g, g') =
150
    if is_instance_var x || ISet.mem x non_inputs then
151
      match (lhs_is_mem, ISet.mem x mems) with
152
      | (false, true ) -> (add_edges [x] lhs g, g'                  )
153
      | (false, false) -> (add_edges lhs [x] g, g'                  )
154
      | (true , false) -> (add_edges lhs [x] g, g'                  )
155
      | (true , true ) -> (g                  , add_edges [x] lhs g')
156
    else (g, g') in
157
(* Add dependencies from [lhs] to rhs clock [ck]. *)
158
  let rec add_clock lhs_is_mem lhs ck g =
159
    (*Format.eprintf "add_clock %a@." Clocks.print_ck ck;*)
160
    match (Clocks.repr ck).Clocks.cdesc with
161
    | Clocks.Con (ck', cr, _)   -> add_var lhs_is_mem lhs (Clocks.const_of_carrier cr) (add_clock lhs_is_mem lhs ck' g)
162
    | Clocks.Ccarrying (_, ck') -> add_clock lhs_is_mem lhs ck' g
163
    | _                         -> g 
164
  in
165
  
166

    
167
  let rec add_dep lhs_is_mem lhs rhs g =
168
    
169
    (* Add mashup dependencies for a user-defined node instance [lhs] = [f]([e]) *)
170
    (* i.e every input is connected to every output, through a ghost var *)
171
    let mashup_appl_dependencies f e g =
172
      let f_var = mk_instance_var (sprintf "%s_%d" f eq.eq_loc.Location.loc_start.Lexing.pos_lnum) in
173
      List.fold_right (fun rhs -> add_dep lhs_is_mem (adjust_tuple f_var rhs) rhs)
174
	(expr_list_of_expr e) (add_var lhs_is_mem lhs f_var g) 
175
    in
176
    match rhs.expr_desc with
177
    | Expr_const _    -> g
178
    | Expr_fby (e1, e2)  -> add_dep true lhs e2 (add_dep false lhs e1 g)
179
    | Expr_pre e      -> add_dep true lhs e g
180
    | Expr_ident x -> add_var lhs_is_mem lhs x (add_clock lhs_is_mem lhs rhs.expr_clock g)
181
    | Expr_access (e1, _)
182
    | Expr_power (e1, _) -> add_dep lhs_is_mem lhs e1 g
183
    | Expr_array a -> List.fold_right (add_dep lhs_is_mem lhs) a g
184
    | Expr_tuple t ->       
185
      if List.length t <> List.length lhs then ( 
186
	match lhs with
187
	| [l] -> List.fold_right (fun r -> add_dep lhs_is_mem [l] r) t g
188
	| _ -> 
189
	  Format.eprintf "Incompatible tuple assign: %a (%i) vs %a (%i)@.@?" 
190
	    (Utils.fprintf_list ~sep:"," (Format.pp_print_string)) lhs 
191
	    (List.length lhs)
192
	    Printers.pp_expr rhs
193
	    (List.length t)
194
	  ;
195
	  assert false
196
      ) 
197
      else
198
	List.fold_right2 (fun l r -> add_dep lhs_is_mem [l] r) lhs t g
199
    | Expr_merge (c, hl) -> add_var lhs_is_mem lhs c (List.fold_right (fun (_, h) -> add_dep lhs_is_mem lhs h) hl g)
200
    | Expr_ite   (c, t, e) -> add_dep lhs_is_mem lhs c (add_dep lhs_is_mem lhs t (add_dep lhs_is_mem lhs e g))
201
    | Expr_arrow (e1, e2)  -> add_dep lhs_is_mem lhs e2 (add_dep lhs_is_mem lhs e1 g)
202
    | Expr_when  (e, c, _)  -> add_dep lhs_is_mem lhs e (add_var lhs_is_mem lhs c g)
203
    | Expr_appl (f, e, None) ->
204
      if Basic_library.is_internal_fun f
205
      (* tuple component-wise dependency for internal operators *)
206
      then
207
	List.fold_right (add_dep lhs_is_mem lhs) (expr_list_of_expr e) g
208
      (* mashed up dependency for user-defined operators *)
209
      else
210
	mashup_appl_dependencies f e g
211
    | Expr_appl (f, e, Some (r, _)) ->
212
      mashup_appl_dependencies f e (add_var lhs_is_mem lhs r g)
213
      
214
  in
215
  add_dep false eq.eq_lhs eq.eq_rhs (add_vertices eq.eq_lhs g, g')
216
  
217

    
218
(* Returns the dependence graph for node [n] *)
219
let dependence_graph mems non_inputs n =
220
  eq_var_cpt := 0;
221
  instance_var_cpt := 0;
222
  let g = new_graph (), new_graph () in
223
  (* Basic dependencies *)
224
  let g = List.fold_right (add_eq_dependencies mems non_inputs) n.node_eqs g in
225
  g
226

    
227
end
228

    
229
module NodeDep = struct
230

    
231
  module ExprModule =
232
  struct
233
    type t = expr
234
    let compare = compare
235
    let hash n = Hashtbl.hash n
236
    let equal n1 n2 = n1 = n2
237
  end
238

    
239
  module ESet = Set.Make(ExprModule)
240

    
241
  let rec get_expr_calls prednode expr = 
242
    match expr.expr_desc with
243
      | Expr_const _ 
244
      | Expr_ident _ -> ESet.empty
245
      | Expr_access (e, _)
246
      | Expr_power (e, _) -> get_expr_calls prednode e
247
      | Expr_array t
248
      | Expr_tuple t -> List.fold_right (fun x set -> ESet.union (get_expr_calls prednode x) set) t ESet.empty
249
      | Expr_merge (_,hl) -> List.fold_right (fun (_,h) set -> ESet.union (get_expr_calls prednode h) set) hl ESet.empty
250
      | Expr_fby (e1,e2)
251
      | Expr_arrow (e1,e2) -> ESet.union (get_expr_calls prednode e1) (get_expr_calls prednode e2)
252
      | Expr_ite   (c, t, e) -> ESet.union (get_expr_calls prednode c) (ESet.union (get_expr_calls prednode t) (get_expr_calls prednode e))
253
      | Expr_pre e 
254
      | Expr_when (e,_,_) -> get_expr_calls prednode e
255
      | Expr_appl (id,e, _) ->
256
	if not (Basic_library.is_internal_fun id) && prednode id
257
	then ESet.add expr (get_expr_calls prednode e)
258
	else (get_expr_calls prednode e)
259

    
260
  let get_callee expr =
261
    match expr.expr_desc with
262
    | Expr_appl (id, args, _) -> Some (id, expr_list_of_expr args)
263
    | _ -> None
264

    
265
  let get_calls prednode eqs =
266
    let deps =
267
      List.fold_left 
268
	(fun accu eq -> ESet.union accu (get_expr_calls prednode eq.eq_rhs))
269
	ESet.empty
270
	eqs in
271
    ESet.elements deps
272

    
273
  let dependence_graph prog =
274
  let g = new_graph () in
275
  let g = List.fold_right 
276
    (fun td accu -> (* for each node we add its dependencies *)
277
      match td.top_decl_desc with 
278
	| Node nd ->
279
	  (*Format.eprintf "Computing deps of node %s@.@?" nd.node_id; *)
280
	  let accu = add_vertices [nd.node_id] accu in
281
	  let deps = List.map (fun e -> fst (desome (get_callee e))) (get_calls (fun _ -> true) nd.node_eqs) in
282
	   (*Format.eprintf "%a@.@?" (Utils.fprintf_list ~sep:"@." Format.pp_print_string) deps; *)
283
	  add_edges [nd.node_id] deps accu
284
	| _ -> assert false (* should not happen *)
285
      
286
    ) prog g in
287
  g   
288

    
289
  let rec filter_static_inputs inputs args =
290
   match inputs, args with
291
   | []   , [] -> []
292
   | v::vq, a::aq -> if v.var_dec_const then (dimension_of_expr a) :: filter_static_inputs vq aq else filter_static_inputs vq aq
293
   | _ -> assert false
294

    
295
  let compute_generic_calls prog =
296
    List.iter
297
      (fun td ->
298
	match td.top_decl_desc with 
299
	| Node nd ->
300
	  let prednode n = is_generic_node (Hashtbl.find node_table n) in
301
	  nd.node_gencalls <- get_calls prednode nd.node_eqs
302
	| _ -> ()
303
      
304
      ) prog
305

    
306
end
307

    
308
module CycleDetection = struct
309

    
310
(* ---- Look for cycles in a dependency graph *)
311
  module Cycles = Graph.Components.Make (IdentDepGraph)
312

    
313
  let mk_copy_var n id =
314
    mk_new_name (node_vars n) id
315

    
316
  let mk_copy_eq n var =
317
    let var_decl = node_var var n in
318
    let cp_var = mk_copy_var n var in
319
    let expr =
320
      { expr_tag = Utils.new_tag ();
321
	expr_desc = Expr_ident var;
322
	expr_type = var_decl.var_type;
323
	expr_clock = var_decl.var_clock;
324
	expr_delay = Delay.new_var ();
325
	expr_annot = None;
326
	expr_loc = var_decl.var_loc } in
327
    { var_decl with var_id = cp_var },
328
    mkeq var_decl.var_loc ([cp_var], expr)
329

    
330
  let wrong_partition g partition =
331
    match partition with
332
    | [id]    -> IdentDepGraph.mem_edge g id id
333
    | _::_::_ -> true
334
    | []      -> assert false
335

    
336
(* Checks that the dependency graph [g] does not contain a cycle. Raises
337
   [Cycle partition] if the succession of dependencies [partition] forms a cycle *)
338
  let check_cycles g =
339
    let scc_l = Cycles.scc_list g in
340
    List.iter (fun partition ->
341
      if wrong_partition g partition then
342
	raise (Cycle partition)
343
      else ()
344
    ) scc_l
345

    
346
(* Creates the sub-graph of [g] restricted to vertices and edges in partition *)
347
  let copy_partition g partition =
348
    let copy_g = IdentDepGraph.create () in
349
    IdentDepGraph.iter_edges
350
      (fun src tgt ->
351
	if List.mem src partition && List.mem tgt partition
352
	then IdentDepGraph.add_edge copy_g src tgt)
353
      g
354

    
355
 
356
(* Breaks dependency cycles in a graph [g] by inserting aux variables.
357
  [head] is a head of a non-trivial scc of [g]. 
358
   In Lustre, this is legal only for mem/mem cycles *)
359
  let break_cycle head cp_head g =
360
    let succs = IdentDepGraph.succ g head in
361
    IdentDepGraph.add_edge g head cp_head;
362
    List.iter
363
      (fun s ->
364
	IdentDepGraph.remove_edge g head s;
365
	IdentDepGraph.add_edge    g s cp_head)
366
      succs
367

    
368
(* Breaks cycles of the dependency graph [g] of memory variables [mems]
369
   belonging in node [node]. Returns:
370
   - a list of new auxiliary variable declarations
371
   - a list of new equations
372
   - a modified acyclic version of [g]
373
*)
374
  let break_cycles node mems g =
375
    let (mem_eqs, non_mem_eqs) = List.partition (fun eq -> List.exists (fun v -> ISet.mem v mems) eq.eq_lhs) node.node_eqs in
376
    let rec break vdecls mem_eqs g =
377
      let scc_l = Cycles.scc_list g in
378
      let wrong = List.filter (wrong_partition g) scc_l in
379
      match wrong with
380
      | []              -> (vdecls, non_mem_eqs@mem_eqs, g)
381
      | [head]::_       ->
382
	begin
383
	  IdentDepGraph.remove_edge g head head;
384
	  break vdecls mem_eqs g
385
	end
386
      | (head::part)::_ -> 
387
	begin
388
	  let vdecl_cp_head, cp_eq = mk_copy_eq node head in
389
	  let pvar v = List.mem v part in
390
	  let fvar v = if v = head then vdecl_cp_head.var_id else v in
391
	  let mem_eqs' = List.map (eq_replace_rhs_var pvar fvar) mem_eqs in
392
	  break_cycle head vdecl_cp_head.var_id g;
393
	  break (vdecl_cp_head::vdecls) (cp_eq::mem_eqs') g
394
	end
395
      | _               -> assert false
396
    in break [] mem_eqs g
397

    
398
end
399

    
400
(* Module used to compute static disjunction of variables based upon their clocks. *)
401
module Disjunction =
402
struct
403
  (* map: var |-> list of disjoint vars, sorted in increasing branch length,
404
     maybe removing shorter branches *)
405
  type clock_map = (ident, ident list) Hashtbl.t
406

    
407
  let rec add_vdecl map vdecls =
408
    match vdecls with
409
    | []         -> ()
410
    | vdecl :: q -> begin
411
		      Hashtbl.add map vdecl.var_id (List.fold_left (fun r v -> if Clocks.disjoint v.var_clock vdecl.var_clock then v.var_id::r else r) [] q);
412
                      add_vdecl map q
413
		    end
414

    
415
  let clock_disjoint_map vdecls =
416
    let root_branch vdecl = Clocks.root vdecl.var_clock, Clocks.branch vdecl.var_clock in
417
    let map = Hashtbl.create 23 in
418
    begin
419
      add_vdecl map (List.sort (fun v1 v2 -> compare (root_branch v1) (root_branch v2)) vdecls);
420
      map
421
    end
422

    
423
  let pp_disjoint_map fmt map =
424
    begin
425
      Format.fprintf fmt "{ /* disjoint map */@.";
426
      Hashtbl.iter (fun k v -> Format.fprintf fmt "%s # { %a }@." k (Utils.fprintf_list ~sep:", " Format.pp_print_string) v) map;
427
      Format.fprintf fmt "}@."
428
    end
429
end
430

    
431
let pp_dep_graph fmt g =
432
  begin
433
    Format.fprintf fmt "{ /* graph */@.";
434
    IdentDepGraph.iter_edges (fun s t -> Format.fprintf fmt "%s -> %s@." s t) g;
435
    Format.fprintf fmt "}@."
436
  end
437

    
438
let pp_error fmt trace =
439
  fprintf fmt "@.Causality error, cyclic data dependencies: %a@."
440
    (fprintf_list ~sep:"->" pp_print_string) trace
441

    
442
(* Merges elements of graph [g2] into graph [g1] *)
443
let merge_with g1 g2 =
444
    IdentDepGraph.iter_vertex (fun v -> IdentDepGraph.add_vertex g1 v) g2;
445
    IdentDepGraph.iter_edges (fun s t -> IdentDepGraph.add_edge g1 s t) g2
446

    
447
let global_dependency node =
448
  let mems = ExprDep.node_memory_variables node in
449
  let non_inputs = ExprDep.node_non_input_variables node in
450
  let (g_non_mems, g_mems) = ExprDep.dependence_graph mems non_inputs node in
451
  (*Format.eprintf "g_non_mems: %a" pp_dep_graph g_non_mems;
452
  Format.eprintf "g_mems: %a" pp_dep_graph g_mems;*)
453
  CycleDetection.check_cycles g_non_mems;
454
  let (vdecls', eqs', g_mems') = CycleDetection.break_cycles node mems g_mems in
455
  (*Format.eprintf "g_mems': %a" pp_dep_graph g_mems';*)
456
  merge_with g_non_mems g_mems';
457
  { node with node_eqs = eqs'; node_locals = vdecls'@node.node_locals }, 
458
  g_non_mems
459

    
460

    
461
(* Local Variables: *)
462
(* compile-command:"make -C .." *)
463
(* End: *)
(5-5/49)