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
|
open Types
open Values
open CfimAst
type binder = {
index : VarId.id; (** Unique variable identifier *)
name : string option; (** Possible name *)
}
[@@deriving show]
(** A binder used in an environment, to map a variable to a value *)
(** Environment value: mapping from variable to value, abstraction (only
used in symbolic mode) or stack frame delimiter.
TODO: rename? Environment element or something?
*)
type env_value = Var of binder * typed_value | Abs of abs | Frame
[@@deriving show]
type env = env_value list [@@deriving show]
type interpreter_mode = ConcreteMode | SymbolicMode [@@deriving show]
type config = { mode : interpreter_mode; check_invariants : bool }
[@@deriving show]
type eval_ctx = {
type_context : type_def list;
fun_context : fun_def list;
type_vars : type_var list;
env : env;
symbolic_counter : SymbolicValueId.generator;
borrow_counter : BorrowId.generator;
}
[@@deriving show]
(** Evaluation context *)
let fresh_symbolic_value_id (ctx : eval_ctx) : eval_ctx * SymbolicValueId.id =
let id, counter' = SymbolicValueId.fresh ctx.symbolic_counter in
({ ctx with symbolic_counter = counter' }, id)
let fresh_borrow_id (ctx : eval_ctx) : eval_ctx * BorrowId.id =
let id, counter' = BorrowId.fresh ctx.borrow_counter in
({ ctx with borrow_counter = counter' }, id)
let lookup_type_var (ctx : eval_ctx) (vid : TypeVarId.id) : type_var =
TypeVarId.nth ctx.type_vars vid
let ctx_lookup_binder (ctx : eval_ctx) (vid : VarId.id) : binder =
(* TOOD: we might want to stop at the end of the frame *)
let rec lookup env =
match env with
| [] ->
raise (Invalid_argument ("Variable not found: " ^ VarId.to_string vid))
| Var (var, _) :: env' -> if var.index = vid then var else lookup env'
| (Abs _ | Frame) :: env' -> lookup env'
in
lookup ctx.env
let ctx_lookup_type_def (ctx : eval_ctx) (tid : TypeDefId.id) : type_def =
TypeDefId.nth ctx.type_context tid
let ctx_lookup_fun_def (ctx : eval_ctx) (fid : FunDefId.id) : fun_def =
FunDefId.nth ctx.fun_context fid
(** Retrieve a variable's value in an environment *)
let env_lookup_var_value (env : env) (vid : VarId.id) : typed_value =
(* We take care to stop at the end of current frame: different variables
in different frames can have the same id!
*)
let rec lookup env =
match env with
| [] -> failwith "Unexpected"
| Var (var, v) :: env' -> if var.index = vid then v else lookup env'
| Abs _ :: env' -> lookup env'
| Frame :: _ -> failwith "End of frame"
in
lookup env
(** Retrieve a variable's value in an evaluation context *)
let ctx_lookup_var_value (ctx : eval_ctx) (vid : VarId.id) : typed_value =
env_lookup_var_value ctx.env vid
(** Update a variable's value in an environment
This is a helper function: it can break invariants and doesn't perform
any check.
*)
let env_update_var_value (env : env) (vid : VarId.id) (nv : typed_value) : env =
(* We take care to stop at the end of current frame: different variables
in different frames can have the same id!
*)
let rec update env =
match env with
| [] -> failwith "Unexpected"
| Var (var, v) :: env' ->
if var.index = vid then Var (var, nv) :: env'
else Var (var, v) :: update env'
| Abs abs :: env' -> Abs abs :: update env'
| Frame :: _ -> failwith "End of frame"
in
update env
let var_to_binder (var : var) : binder = { index = var.index; name = var.name }
(** Update a variable's value in an evaluation context.
This is a helper function: it can break invariants and doesn't perform
any check.
*)
let ctx_update_var_value (ctx : eval_ctx) (vid : VarId.id) (nv : typed_value) :
eval_ctx =
{ ctx with env = env_update_var_value ctx.env vid nv }
(** Push a variable in the context's environment.
Checks that the pushed variable and its value have the same type (this
is important).
*)
let ctx_push_var (ctx : eval_ctx) (var : var) (v : typed_value) : eval_ctx =
assert (var.var_ty = v.ty);
let bv = var_to_binder var in
{ ctx with env = Var (bv, v) :: ctx.env }
(** Push a list of variables.
Checks that the pushed variables and their values have the same type (this
is important).
*)
let ctx_push_vars (ctx : eval_ctx) (vars : (var * typed_value) list) : eval_ctx
=
assert (List.for_all (fun (var, value) -> var.var_ty = value.ty) vars);
let vars =
List.map (fun (var, value) -> Var (var_to_binder var, value)) vars
in
let vars = List.rev vars in
{ ctx with env = List.append vars ctx.env }
let mk_bottom (ty : ety) : typed_value = { value = Bottom; ty }
(** Push an uninitialized variable (which thus maps to [Bottom]) *)
let ctx_push_uninitialized_var (ctx : eval_ctx) (var : var) : eval_ctx =
ctx_push_var ctx var (mk_bottom var.var_ty)
(** Push a list of uninitialized variables (which thus map to [Bottom]) *)
let ctx_push_uninitialized_vars (ctx : eval_ctx) (vars : var list) : eval_ctx =
let vars = List.map (fun v -> (v, mk_bottom v.var_ty)) vars in
ctx_push_vars ctx vars
|
