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-rw-r--r--src/Interpreter.ml133
-rw-r--r--src/Values.ml4
2 files changed, 101 insertions, 36 deletions
diff --git a/src/Interpreter.ml b/src/Interpreter.ml
index 8c2ebb63..ee69a39d 100644
--- a/src/Interpreter.ml
+++ b/src/Interpreter.ml
@@ -761,11 +761,13 @@ let bottom_in_value (v : V.typed_value) : bool =
Note that this function is very general: it also checks wether
symbolic values contain already ended regions.
+
+ TODO: remove?
*)
-let bottom_in_avalue (v : V.typed_avalue) (abs_regions : T.RegionId.set_t) :
+let bottom_in_avalue (v : V.typed_avalue) (_abs_regions : T.RegionId.set_t) :
bool =
let obj =
- object (self)
+ object
inherit [_] V.iter_typed_avalue
method! visit_Bottom _ = raise Found
@@ -773,7 +775,7 @@ let bottom_in_avalue (v : V.typed_avalue) (abs_regions : T.RegionId.set_t) :
method! visit_symbolic_proj_comp _ sv =
if symbolic_proj_comp_ended_regions sv then raise Found else ()
- method! visit_aproj env ap =
+ method! visit_aproj _ ap =
(* Nothing to do actually *)
match ap with
| V.AProjLoans _sv -> ()
@@ -1017,36 +1019,39 @@ let symbolic_expansion_non_borrow_to_value (sv : V.symbolic_value)
in
V.Adt { V.variant_id; V.field_values }
| SeMutRef (_, _) | SeSharedRef (_, _) ->
- failwith "Unexpected symbolic borrow expansion"
+ failwith "Unexpected symbolic reference expansion"
in
{ V.value; V.ty }
(** Convert a symbolic expansion to a value.
- If the expansion is a reference expansion, it converts it to a borrow.
+ If the expansion is a mutable reference expansion, it converts it to a borrow.
This function is meant to be used when reducing projectors over borrows,
during a symbolic expansion.
*)
-let symbolic_expansion_to_value_with_borrows (sv : V.symbolic_value)
+let symbolic_expansion_non_shared_borrow_to_value (sv : V.symbolic_value)
(see : symbolic_expansion) : V.typed_value =
match see with
- | SeMutRef (_, _) -> raise Unimplemented
+ | SeMutRef (bid, bv) ->
+ let ty = Subst.erase_regions sv.V.sv_ty in
+ let bv = mk_typed_value_from_proj_comp bv in
+ let value = V.Borrow (V.MutBorrow (bid, bv)) in
+ { V.value; ty }
| SeSharedRef (_, _) ->
- raise Unimplemented failwith "Unexpected symbolic borrow expansion"
+ failwith "Unexpected symbolic shared reference expansion"
| _ -> symbolic_expansion_non_borrow_to_value sv see
(** Apply (and reduce) a projector over loans to a value.
TODO: detailed comments. See [apply_proj_borrows]
*)
-let apply_proj_loans_on_symbolic_expansion (ctx : C.eval_ctx)
- (regions : T.RegionId.set_t) (see : symbolic_expansion) (ty : T.rty) :
- V.typed_avalue =
+let apply_proj_loans_on_symbolic_expansion (regions : T.RegionId.set_t)
+ (see : symbolic_expansion) (ty : T.rty) : V.typed_avalue =
(* Match *)
let value : V.avalue =
match (see, ty) with
| SeConcrete cv, (T.Bool | T.Char | T.Integer _ | T.Str) -> V.AConcrete cv
- | SeAdt (variant_id, field_values), T.Adt (id, _region_params, _tys) ->
+ | SeAdt (variant_id, field_values), T.Adt (_id, _region_params, _tys) ->
(* Project over the field values *)
let field_values =
List.map mk_aproj_loans_from_proj_comp field_values
@@ -2160,7 +2165,7 @@ and end_abstraction_borrows (config : C.config) (abs_id : V.AbstractionId.id)
contains regions which we are ending.
Of course, we ignore the abstraction we are currently ending...
*)
-and end_abstraction_regions (config : C.config) (abs_id : V.AbstractionId.id)
+and end_abstraction_regions (_config : C.config) (abs_id : V.AbstractionId.id)
(ctx : C.eval_ctx) : C.eval_ctx =
(* Lookup the abstraction to retrieve the set of owned regions *)
let abs = C.ctx_lookup_abs ctx abs_id in
@@ -2704,6 +2709,17 @@ type proj_kind = LoanProj | BorrowProj
[allow_reborrows] controls whether we allow reborrows or not. It is useful
only if we target borrow projectors.
+
+ Also, if this function is called on an expansion for *shared references*,
+ the proj borrows should already have been expanded.
+
+ TODO: the way this function is used is a bit complex, especially because of
+ the above condition. Maybe we should have:
+ 1. a generic function to expand the loan projectors
+ 2. a function to expand the borrow projectors for non-borrows
+ 3. specialized functions for mut borrows and shared borrows
+ Note that 2. and 3. may have a little bit of duplicated code, but hopefully
+ it would make things clearer.
*)
let apply_symbolic_expansion_to_target_avalues (config : C.config)
(allow_reborrows : bool) (proj_kind : proj_kind)
@@ -2735,8 +2751,8 @@ let apply_symbolic_expansion_to_target_avalues (config : C.config)
if sv = original_sv then
(* Apply the projector *)
let projected_value =
- apply_proj_loans_on_symbolic_expansion ctx proj_regions
- expansion sv.V.sv_ty
+ apply_proj_loans_on_symbolic_expansion proj_regions expansion
+ sv.V.sv_ty
in
(* Replace *)
projected_value.V.value
@@ -2750,7 +2766,8 @@ let apply_symbolic_expansion_to_target_avalues (config : C.config)
* apply a projector (if the expansion is a reference expansion,
* convert it to a borrow) *)
let expansion =
- symbolic_expansion_to_value_with_borrows original_sv expansion
+ symbolic_expansion_non_shared_borrow_to_value original_sv
+ expansion
in
(* Apply the projector *)
let projected_value =
@@ -2792,7 +2809,7 @@ let apply_symbolic_expansion_to_avalues (config : C.config)
Simply replace the symbolic values (*not avalues*) in the context with
a given value. Will break invariants if not used properly.
*)
-let replace_symbolic_values (config : C.config) (at_most_once : bool)
+let replace_symbolic_values (at_most_once : bool)
(original_sv : V.symbolic_value) (nv : V.value) (ctx : C.eval_ctx) :
C.eval_ctx =
(* Count *)
@@ -2829,9 +2846,7 @@ let apply_symbolic_expansion_non_borrow (config : C.config)
(* Apply the expansion to non-abstraction values *)
let nv = symbolic_expansion_non_borrow_to_value original_sv expansion in
let at_most_once = false in
- let ctx =
- replace_symbolic_values config at_most_once original_sv nv.V.value ctx
- in
+ let ctx = replace_symbolic_values at_most_once original_sv nv.V.value ctx in
(* Apply the expansion to abstraction values *)
let allow_reborrows = false in
apply_symbolic_expansion_to_avalues config allow_reborrows original_sv
@@ -2949,7 +2964,6 @@ let expand_bottom_value_from_projection (config : C.config)
*)
let compute_expanded_symbolic_adt_value (expand_enumerations : bool)
(ended_regions : T.RegionId.set_t) (def_id : T.TypeDefId.id)
- (opt_variant_id : T.VariantId.id option)
(regions : T.RegionId.id T.region list) (types : T.rty list)
(ctx : C.eval_ctx) : (C.eval_ctx * symbolic_expansion) list =
(* Lookup the definition and check if it is an enumeration with several
@@ -3003,12 +3017,11 @@ let compute_expanded_symbolic_box_value (ended_regions : T.RegionId.set_t)
let expand_symbolic_value_shared_borrow (config : C.config)
(original_sv : V.symbolic_value) (ended_regions : T.RegionId.set_t)
- (region : T.RegionId.id T.region) (ref_ty : T.rty) (rkind : T.ref_kind)
- (ctx : C.eval_ctx) : C.eval_ctx =
- (* First, replace the symbolic values. The important point is that the
- * symbolic value to expand may appear several times, if it has been
- * copied. In this case, we need to introduce one fresh borrow id per
- * instance.
+ (ref_ty : T.rty) (ctx : C.eval_ctx) : C.eval_ctx =
+ (* First, replace the projectors on borrows (AProjBorrow and proj_comp)
+ * The important point is that the symbolic value to expand may appear
+ * several times, if it has been copied. In this case, we need to introduce
+ * one fresh borrow id per instance.
*)
let borrows = ref V.BorrowId.Set.empty in
let borrow_counter = ref ctx.C.borrow_counter in
@@ -3018,7 +3031,28 @@ let expand_symbolic_value_shared_borrow (config : C.config)
borrows := V.BorrowId.Set.add bid' !borrows;
bid'
in
- (* Visitor to replace the symbolic values *)
+ (* Small utility used on shared borrows in abstractions (regular borrow
+ * projector and asb).
+ * Returns `Some` if the symbolic value has been expanded to an asb list,
+ * `None` otherwise *)
+ let reborrow_ashared proj_regions (sv : V.symbolic_value) (proj_ty : T.rty) :
+ V.abstract_shared_borrows option =
+ if sv = original_sv then
+ match proj_ty with
+ | T.Ref (r, ref_ty, T.Shared) ->
+ (* Projector over the shared value *)
+ let shared_asb = V.AsbProjReborrows (sv, ref_ty) in
+ (* Check if the region is in the set of projected regions *)
+ if region_in_set r proj_regions then
+ (* In the set: we need to reborrow *)
+ let bid = fresh_borrow () in
+ Some [ V.AsbBorrow bid; shared_asb ]
+ else (* Not in the set: ignore *)
+ Some [ shared_asb ]
+ | _ -> failwith "Unexpected"
+ else None
+ in
+ (* Visitor to replace the projectors on borrows *)
let obj =
object
inherit [_] C.map_eval_ctx as super
@@ -3028,12 +3062,41 @@ let expand_symbolic_value_shared_borrow (config : C.config)
let bid = fresh_borrow () in
V.Borrow (V.SharedBorrow bid)
else super#visit_Symbolic env sv
+
+ method! visit_Abs proj_regions abs =
+ assert (Option.is_none proj_regions);
+ let proj_regions = Some abs.V.regions in
+ super#visit_Abs proj_regions abs
+
+ method! visit_AProjSharedBorrow proj_regions asb =
+ let expand_asb (asb : V.abstract_shared_borrow) :
+ V.abstract_shared_borrows =
+ match asb with
+ | V.AsbBorrow _ -> [ asb ]
+ | V.AsbProjReborrows (sv, proj_ty) -> (
+ match reborrow_ashared (Option.get proj_regions) sv proj_ty with
+ | None -> [ asb ]
+ | Some asb -> asb)
+ in
+ let asb = List.concat (List.map expand_asb asb) in
+ V.AProjSharedBorrow asb
+
+ method! visit_ASymbolic proj_regions aproj =
+ match aproj with
+ | AProjLoans _ ->
+ (* Loans are handled later *)
+ super#visit_ASymbolic proj_regions aproj
+ | AProjBorrows (sv, proj_ty) -> (
+ (* Check if we need to reborrow *)
+ match reborrow_ashared (Option.get proj_regions) sv proj_ty with
+ | None -> super#visit_ASymbolic proj_regions aproj
+ | Some asb -> V.ABorrow (V.AProjSharedBorrow asb))
end
in
(* Call the visitor *)
- let ctx = obj#visit_eval_ctx () ctx in
+ let ctx = obj#visit_eval_ctx None ctx in
let ctx = { ctx with C.borrow_counter = !borrow_counter } in
- (* Finally, replace the symbolic avalues *)
+ (* Finally, replace the projectors on loans *)
let bids = !borrows in
assert (not (V.BorrowId.Set.is_empty bids));
let ctx, shared_sv = mk_fresh_symbolic_proj_comp ended_regions ref_ty ctx in
@@ -3057,10 +3120,10 @@ let expand_symbolic_value_borrow (config : C.config)
let see = SeMutRef (bid, sv) in
(* Expand the symbolic values - we simply perform a substitution (and
* check that we perform exactly one substitution) *)
- let nv = symbolic_expansion_to_value_with_borrows original_sv see in
+ let nv = symbolic_expansion_non_shared_borrow_to_value original_sv see in
let at_most_once = true in
let ctx =
- replace_symbolic_values config at_most_once original_sv nv.V.value ctx
+ replace_symbolic_values at_most_once original_sv nv.V.value ctx
in
(* Expand the symbolic avalues *)
let allow_reborrows = true in
@@ -3068,7 +3131,7 @@ let expand_symbolic_value_borrow (config : C.config)
ctx
| T.Shared ->
expand_symbolic_value_shared_borrow config original_sv ended_regions
- region ref_ty rkind ctx
+ ref_ty ctx
(** Expand a symbolic value which is not an enumeration with several variants.
@@ -3082,7 +3145,7 @@ let expand_symbolic_value_non_enum (config : C.config) (pe : E.projection_elem)
let ended_regions = sp.V.rset_ended in
match (pe, rty) with
(* "Regular" ADTs *)
- | ( Field (ProjAdt (def_id, opt_variant_id), _),
+ | ( Field (ProjAdt (def_id, _opt_variant_id), _),
T.Adt (T.AdtId def_id', regions, types) ) -> (
assert (def_id = def_id');
(* Compute the expanded value - there should be exactly one because we
@@ -3090,7 +3153,7 @@ let expand_symbolic_value_non_enum (config : C.config) (pe : E.projection_elem)
let expand_enumerations = false in
match
compute_expanded_symbolic_adt_value expand_enumerations ended_regions
- def_id opt_variant_id regions types ctx
+ def_id regions types ctx
with
| [ (ctx, nv) ] ->
(* Apply in the context *)
diff --git a/src/Values.ml b/src/Values.ml
index c1b84805..a4dde6ea 100644
--- a/src/Values.ml
+++ b/src/Values.ml
@@ -49,6 +49,7 @@ type symbolic_value = { sv_id : SymbolicValueId.id; sv_ty : rty }
[@@deriving show]
(** Symbolic value *)
+(** TODO: make it clear that complementary projectors are projectors on borrows *)
type symbolic_proj_comp = {
svalue : symbolic_value; (** The symbolic value itself *)
rset_ended : RegionId.set_t;
@@ -101,7 +102,8 @@ type value =
| Bottom (** No value (uninitialized or moved value) *)
| Borrow of borrow_content (** A borrowed value *)
| Loan of loan_content (** A loaned value *)
- | Symbolic of symbolic_proj_comp (** Unknown (symbolic) value *)
+ | Symbolic of symbolic_proj_comp
+ (** Unknown (symbolic) value. This is a projector on borrows (TODO: make this clearer). *)
and adt_value = {
variant_id : (VariantId.id option[@opaque]);