1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
(**************************************************************************)
(* *)
(* OCaml *)
(* *)
(* Pierre Chambart, OCamlPro *)
(* Mark Shinwell and Leo White, Jane Street Europe *)
(* *)
(* Copyright 2013--2016 OCamlPro SAS *)
(* Copyright 2014--2016 Jane Street Group LLC *)
(* *)
(* All rights reserved. This file is distributed under the terms of *)
(* the GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
[@@@ocaml.warning "+a-4-9-30-40-41-42"]
module A = Simple_value_approx
module C = Inlining_cost
type lifter = Flambda.program -> Flambda.program
let rebuild_let
(defs : (Variable.t * Flambda.named Flambda.With_free_variables.t) list)
(body : Flambda.t) =
let module W = Flambda.With_free_variables in
List.fold_left (fun body (var, def) ->
W.create_let_reusing_defining_expr var def body)
body defs
let rec extract_lets
(acc:(Variable.t * Flambda.named Flambda.With_free_variables.t) list)
(let_expr:Flambda.let_expr) :
(Variable.t * Flambda.named Flambda.With_free_variables.t) list *
Flambda.t Flambda.With_free_variables.t =
let module W = Flambda.With_free_variables in
match let_expr with
| { var = v1; defining_expr = Expr (Let let2); _ } ->
let acc, body2 = extract_lets acc let2 in
let acc = (v1, W.expr body2) :: acc in
let body = W.of_body_of_let let_expr in
extract acc body
| { var = v; _ } ->
let acc = (v, W.of_defining_expr_of_let let_expr) :: acc in
let body = W.of_body_of_let let_expr in
extract acc body
and extract acc (expr : Flambda.t Flambda.With_free_variables.t) =
let module W = Flambda.With_free_variables in
match W.contents expr with
| Let let_expr ->
extract_lets acc let_expr
| _ ->
acc, expr
let rec lift_lets_expr (expr:Flambda.t) ~toplevel : Flambda.t =
let module W = Flambda.With_free_variables in
match expr with
| Let let_expr ->
let defs, body = extract_lets [] let_expr in
let rev_defs =
List.rev_map (lift_lets_named_with_free_variables ~toplevel) defs
in
let body = lift_lets_expr (W.contents body) ~toplevel in
rebuild_let (List.rev rev_defs) body
| e ->
Flambda_iterators.map_subexpressions
(lift_lets_expr ~toplevel)
(lift_lets_named ~toplevel)
e
and lift_lets_named_with_free_variables
((var, named):Variable.t * Flambda.named Flambda.With_free_variables.t)
~toplevel : Variable.t * Flambda.named Flambda.With_free_variables.t =
let module W = Flambda.With_free_variables in
match W.contents named with
| Expr e ->
var, W.expr (W.of_expr (lift_lets_expr e ~toplevel))
| Set_of_closures set when not toplevel ->
var,
W.of_named
(Set_of_closures
(Flambda_iterators.map_function_bodies
~f:(lift_lets_expr ~toplevel) set))
| Symbol _ | Const _ | Allocated_const _ | Read_mutable _
| Read_symbol_field (_, _) | Project_closure _ | Move_within_set_of_closures _
| Project_var _ | Prim _ | Set_of_closures _ ->
var, named
and lift_lets_named _var (named:Flambda.named) ~toplevel : Flambda.named =
let module W = Flambda.With_free_variables in
match named with
| Expr e ->
Expr (lift_lets_expr e ~toplevel)
| Set_of_closures set when not toplevel ->
Set_of_closures
(Flambda_iterators.map_function_bodies ~f:(lift_lets_expr ~toplevel) set)
| Symbol _ | Const _ | Allocated_const _ | Read_mutable _
| Read_symbol_field (_, _) | Project_closure _ | Move_within_set_of_closures _
| Project_var _ | Prim _ | Set_of_closures _ ->
named
module Sort_lets = Strongly_connected_components.Make (Variable)
let rebuild_let_rec (defs:(Variable.t * Flambda.named) list) body =
let map = Variable.Map.of_list defs in
let graph =
Variable.Map.map
(fun named ->
Variable.Set.filter (fun v -> Variable.Map.mem v map)
(Flambda.free_variables_named named))
map
in
let components =
Sort_lets.connected_components_sorted_from_roots_to_leaf graph
in
Array.fold_left (fun body (component:Sort_lets.component) ->
match component with
| No_loop v ->
let def = Variable.Map.find v map in
Flambda.create_let v def body
| Has_loop l ->
Flambda.Let_rec
(List.map (fun v -> v, Variable.Map.find v map) l,
body))
body components
let lift_let_rec program =
Flambda_iterators.map_exprs_at_toplevel_of_program program
~f:(Flambda_iterators.map_expr
(fun expr -> match expr with
| Let_rec (defs, body) ->
rebuild_let_rec defs body
| expr -> expr))
let lift_lets program =
let program = lift_let_rec program in
Flambda_iterators.map_exprs_at_toplevel_of_program program
~f:(lift_lets_expr ~toplevel:false)
let lifting_helper exprs ~evaluation_order ~create_body ~name =
let vars, lets =
(* [vars] corresponds elementwise to [exprs]; the order is unchanged. *)
List.fold_right (fun (flam : Flambda.t) (vars, lets) ->
match flam with
| Var v ->
(* Note that [v] is (statically) always an immutable variable. *)
v::vars, lets
| expr ->
let v =
Variable.create name ~current_compilation_unit:
(Compilation_unit.get_current_exn ())
in
v::vars, (v, expr)::lets)
exprs ([], [])
in
let lets =
match evaluation_order with
| `Right_to_left -> lets
| `Left_to_right -> List.rev lets
in
List.fold_left (fun body (v, expr) ->
Flambda.create_let v (Expr expr) body)
(create_body vars) lets
|
