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|
(** This file implements various substitution utilities to instantiate types,
function bodies, etc.
*)
module T = Types
module TU = TypesUtils
module V = Values
module E = Expressions
module A = CfimAst
module C = Contexts
(** Substitute types variables and regions in a type *)
let rec ty_substitute (rsubst : 'r1 -> 'r2)
(tsubst : T.TypeVarId.id -> 'r2 T.ty) (ty : 'r1 T.ty) : 'r2 T.ty =
let open T in
let subst = ty_substitute rsubst tsubst in
(* helper *)
match ty with
| Adt (def_id, regions, tys) ->
Adt (def_id, List.map rsubst regions, List.map subst tys)
| Array aty -> Array (subst aty)
| Slice sty -> Slice (subst sty)
| Ref (r, ref_ty, ref_kind) -> Ref (rsubst r, subst ref_ty, ref_kind)
(* Below variants: we technically return the same value, but because
one has type ['r1 ty] and the other has type ['r2 ty], we need to
deconstruct then reconstruct *)
| Bool -> Bool
| Char -> Char
| Never -> Never
| Integer int_ty -> Integer int_ty
| Str -> Str
| TypeVar vid -> tsubst vid
(** Convert an [rty] to an [ety] by erasing the region variables *)
let erase_regions (ty : T.rty) : T.ety =
ty_substitute (fun _ -> T.Erased) (fun vid -> T.TypeVar vid) ty
(** Erase the regions in a type and substitute the type variables *)
let erase_regions_substitute_types (tsubst : T.TypeVarId.id -> T.ety)
(ty : T.rty) : T.ety =
let rsubst (_ : T.RegionVarId.id T.region) : T.erased_region = T.Erased in
ty_substitute rsubst tsubst ty
(** Create a type substitution from a list of type variable ids and a list of
types (with which to substitute the type variable ids *)
let make_type_subst (var_ids : T.TypeVarId.id list) (tys : 'r T.ty list) :
T.TypeVarId.id -> 'r T.ty =
let ls = List.combine var_ids tys in
let mp =
List.fold_left
(fun mp (k, v) -> T.TypeVarId.Map.add k v mp)
T.TypeVarId.Map.empty ls
in
fun id -> T.TypeVarId.Map.find id mp
(** Instantiate the type variables in an ADT definition, and return the list
of types of the fields for the chosen variant *)
let type_def_get_instantiated_field_type (def : T.type_def)
(opt_variant_id : T.VariantId.id option) (types : T.ety list) : T.ety list =
let ty_subst =
make_type_subst (List.map (fun x -> x.T.index) def.T.type_params) types
in
let fields = TU.type_def_get_fields def opt_variant_id in
List.map
(fun f -> erase_regions_substitute_types ty_subst f.T.field_ty)
fields
(** Return the types of the properly instantiated ADT's variant, provided a
context *)
let ctx_adt_get_instantiated_field_types (ctx : C.eval_ctx)
(def_id : T.TypeDefId.id) (opt_variant_id : T.VariantId.id option)
(types : T.ety list) : T.ety list =
let def = C.ctx_lookup_type_def ctx def_id in
type_def_get_instantiated_field_type def opt_variant_id types
(** Apply a type substitution to a place *)
let place_substitute (_tsubst : T.TypeVarId.id -> T.ety) (p : E.place) : E.place
=
(* There is nothing to do *)
p
(** Apply a type substitution to an operand constant value *)
let operand_constant_value_substitute (_tsubst : T.TypeVarId.id -> T.ety)
(op : E.operand_constant_value) : E.operand_constant_value =
(* There is nothing to do *)
op
(** Apply a type substitution to an operand *)
let operand_substitute (tsubst : T.TypeVarId.id -> T.ety) (op : E.operand) :
E.operand =
let p_subst = place_substitute tsubst in
match op with
| E.Copy p -> E.Copy (p_subst p)
| E.Move p -> E.Move (p_subst p)
| E.Constant (ety, cv) ->
let rsubst x = x in
E.Constant
( ty_substitute rsubst tsubst ety,
operand_constant_value_substitute tsubst cv )
(** Apply a type substitution to an rvalue *)
let rvalue_substitute (tsubst : T.TypeVarId.id -> T.ety) (rv : E.rvalue) :
E.rvalue =
let op_subst = operand_substitute tsubst in
let p_subst = place_substitute tsubst in
match rv with
| E.Use op -> E.Use (op_subst op)
| E.Ref (p, bkind) -> E.Ref (p_subst p, bkind)
| E.UnaryOp (unop, op) -> E.UnaryOp (unop, op_subst op)
| E.BinaryOp (binop, op1, op2) ->
E.BinaryOp (binop, op_subst op1, op_subst op2)
| E.Discriminant p -> E.Discriminant (p_subst p)
| E.Aggregate (kind, ops) ->
let ops = List.map op_subst ops in
let kind =
match kind with
| E.AggregatedTuple -> E.AggregatedTuple
| E.AggregatedAdt (def_id, variant_id, regions, tys) ->
let rsubst x = x in
E.AggregatedAdt
( def_id,
variant_id,
regions,
List.map (ty_substitute rsubst tsubst) tys )
in
E.Aggregate (kind, ops)
(** Apply a type substitution to an assertion *)
let assertion_substitute (tsubst : T.TypeVarId.id -> T.ety) (a : A.assertion) :
A.assertion =
{ A.cond = operand_substitute tsubst a.A.cond; A.expected = a.A.expected }
(** Apply a type substitution to a call *)
let call_substitute (tsubst : T.TypeVarId.id -> T.ety) (call : A.call) : A.call
=
let rsubst x = x in
let type_params = List.map (ty_substitute rsubst tsubst) call.A.type_params in
let args = List.map (operand_substitute tsubst) call.A.args in
let dest = place_substitute tsubst call.A.dest in
(* Putting all the paramters on purpose: we want to get a compiler error if
something moves - we may add a field on which we need to apply a substitution *)
{
func = call.A.func;
region_params = call.A.region_params;
A.type_params;
args;
dest;
}
(** Apply a type substitution to a statement *)
let rec statement_substitute (tsubst : T.TypeVarId.id -> T.ety)
(st : A.statement) : A.statement =
match st with
| A.Assign (p, rvalue) ->
let p = place_substitute tsubst p in
let rvalue = rvalue_substitute tsubst rvalue in
A.Assign (p, rvalue)
| A.FakeRead p ->
let p = place_substitute tsubst p in
A.FakeRead p
| A.SetDiscriminant (p, vid) ->
let p = place_substitute tsubst p in
A.SetDiscriminant (p, vid)
| A.Drop p ->
let p = place_substitute tsubst p in
A.Drop p
| A.Assert assertion ->
let assertion = assertion_substitute tsubst assertion in
A.Assert assertion
| A.Call call ->
let call = call_substitute tsubst call in
A.Call call
| A.Panic | A.Return | A.Break _ | A.Continue _ | A.Nop -> st
| A.Sequence (st1, st2) ->
A.Sequence
(statement_substitute tsubst st1, statement_substitute tsubst st2)
| A.Switch (op, tgts) ->
A.Switch
(operand_substitute tsubst op, switch_targets_substitute tsubst tgts)
| A.Loop le -> A.Loop (statement_substitute tsubst le)
(** Apply a type substitution to switch targets *)
and switch_targets_substitute (tsubst : T.TypeVarId.id -> T.ety)
(tgts : A.switch_targets) : A.switch_targets =
match tgts with
| A.If (st1, st2) ->
A.If (statement_substitute tsubst st1, statement_substitute tsubst st2)
| A.SwitchInt (int_ty, tgts, otherwise) ->
let tgts =
List.map (fun (sv, st) -> (sv, statement_substitute tsubst st)) tgts
in
let otherwise = statement_substitute tsubst otherwise in
A.SwitchInt (int_ty, tgts, otherwise)
(** Apply a type substitution to a function body. Return the local variables
and the body. *)
let fun_def_substitute_in_body (tsubst : T.TypeVarId.id -> T.ety)
(def : A.fun_def) : A.var list * A.statement =
let rsubst r = r in
let locals =
List.map
(fun v -> { v with A.var_ty = ty_substitute rsubst tsubst v.A.var_ty })
def.A.locals
in
let body = statement_substitute tsubst def.body in
(locals, body)
|
