diff options
Diffstat (limited to 'compiler/InterpreterLoopsJoinCtxs.ml')
| -rw-r--r-- | compiler/InterpreterLoopsJoinCtxs.ml | 193 |
1 files changed, 182 insertions, 11 deletions
diff --git a/compiler/InterpreterLoopsJoinCtxs.ml b/compiler/InterpreterLoopsJoinCtxs.ml index 0f61f619..960edb99 100644 --- a/compiler/InterpreterLoopsJoinCtxs.ml +++ b/compiler/InterpreterLoopsJoinCtxs.ml @@ -17,7 +17,7 @@ let log = Logging.loops_join_ctxs_log We do this in order to enforce some structure in the environments: this allows us to find fixed-points. Note that this function needs to be called typically after we merge abstractions together (see {!collapse_ctx} - for instance). + and {!reduce_ctx} for instance). *) let reorder_loans_borrows_in_fresh_abs (span : Meta.span) (old_abs_ids : AbstractionId.Set.t) (ctx : eval_ctx) : eval_ctx = @@ -70,7 +70,7 @@ let reorder_loans_borrows_in_fresh_abs (span : Meta.span) { ctx with env } -(** Collapse an environment. +(** Reduce an environment. We do this to simplify an environment, for the purpose of finding a loop fixed point. @@ -129,6 +129,171 @@ let reorder_loans_borrows_in_fresh_abs (span : Meta.span) This can happen when merging environments (note that such environments are not well-formed - they become well formed again after collapsing). *) +let reduce_ctx (span : Meta.span) (loop_id : LoopId.id) + (merge_funs : merge_duplicates_funcs option) (old_ids : ids_sets) + (ctx0 : eval_ctx) : eval_ctx = + (* Debug *) + log#ldebug + (lazy + ("reduce_ctx:\n\n- fixed_ids:\n" ^ show_ids_sets old_ids ^ "\n\n- ctx0:\n" + ^ eval_ctx_to_string ~span:(Some span) ctx0 + ^ "\n\n")); + + let abs_kind : abs_kind = Loop (loop_id, None, LoopSynthInput) in + let can_end = true in + let destructure_shared_values = true in + let is_fresh_abs_id (id : AbstractionId.id) : bool = + not (AbstractionId.Set.mem id old_ids.aids) + in + let is_fresh_did (id : DummyVarId.id) : bool = + not (DummyVarId.Set.mem id old_ids.dids) + in + (* Convert the dummy values to abstractions (note that when we convert + values to abstractions, the resulting abstraction should be destructured) *) + (* Note that we preserve the order of the dummy values: we replace them with + abstractions in place - this makes matching easier *) + let env = + List.concat + (List.map + (fun ee -> + match ee with + | EAbs _ | EFrame | EBinding (BVar _, _) -> [ ee ] + | EBinding (BDummy id, v) -> + if is_fresh_did id then + let absl = + convert_value_to_abstractions span abs_kind can_end + destructure_shared_values ctx0 v + in + List.map (fun abs -> EAbs abs) absl + else [ ee ]) + ctx0.env) + in + let ctx = { ctx0 with env } in + log#ldebug + (lazy + ("reduce_ctx: after converting values to abstractions:\n" + ^ show_ids_sets old_ids ^ "\n\n- ctx:\n" + ^ eval_ctx_to_string ~span:(Some span) ctx + ^ "\n\n")); + + log#ldebug + (lazy + ("reduce_ctx: after decomposing the shared values in the abstractions:\n" + ^ show_ids_sets old_ids ^ "\n\n- ctx:\n" + ^ eval_ctx_to_string ~span:(Some span) ctx + ^ "\n\n")); + + (* Explore all the *new* abstractions, and compute various maps *) + let explore (abs : abs) = is_fresh_abs_id abs.abs_id in + let ids_maps = + compute_abs_borrows_loans_maps span (merge_funs = None) explore env + in + let { + abs_ids; + abs_to_borrows; + abs_to_loans = _; + abs_to_borrows_loans; + borrow_to_abs = _; + loan_to_abs; + borrow_loan_to_abs; + } = + ids_maps + in + + (* Change the merging behaviour depending on the input parameters *) + let abs_to_borrows, loan_to_abs = + if merge_funs <> None then (abs_to_borrows_loans, borrow_loan_to_abs) + else (abs_to_borrows, loan_to_abs) + in + + (* Merge the abstractions together *) + let merged_abs : AbstractionId.id UnionFind.elem AbstractionId.Map.t = + AbstractionId.Map.of_list + (List.map (fun id -> (id, UnionFind.make id)) abs_ids) + in + + let ctx = ref ctx in + + (* Merge all the mergeable abs. + + We iterate over the abstractions, then over the borrows in the abstractions. + We do this because we want to control the order in which abstractions + are merged (the ids are iterated in increasing order). Otherwise, we + could simply iterate over all the borrows in [borrow_to_abs]... + *) + List.iter + (fun abs_id0 -> + let bids = AbstractionId.Map.find abs_id0 abs_to_borrows in + let bids = BorrowId.Set.elements bids in + List.iter + (fun bid -> + match BorrowId.Map.find_opt bid loan_to_abs with + | None -> (* Nothing to do *) () + | Some abs_ids1 -> + AbstractionId.Set.iter + (fun abs_id1 -> + (* We need to merge - unless we have already merged *) + (* First, find the representatives for the two abstractions (the + representative is the abstraction into which we merged) *) + let abs_ref0 = + UnionFind.find (AbstractionId.Map.find abs_id0 merged_abs) + in + let abs_id0 = UnionFind.get abs_ref0 in + let abs_ref1 = + UnionFind.find (AbstractionId.Map.find abs_id1 merged_abs) + in + let abs_id1 = UnionFind.get abs_ref1 in + (* If the two ids are the same, it means the abstractions were already merged *) + if abs_id0 = abs_id1 then () + else ( + (* We actually need to merge the abstractions *) + + (* Debug *) + log#ldebug + (lazy + ("reduce_ctx: merging abstraction " + ^ AbstractionId.to_string abs_id1 + ^ " into " + ^ AbstractionId.to_string abs_id0 + ^ ":\n\n" + ^ eval_ctx_to_string ~span:(Some span) !ctx)); + + (* Update the environment - pay attention to the order: we + we merge [abs_id1] *into* [abs_id0] *) + let nctx, abs_id = + merge_into_abstraction span abs_kind can_end merge_funs + !ctx abs_id1 abs_id0 + in + ctx := nctx; + + (* Update the union find *) + let abs_ref_merged = UnionFind.union abs_ref0 abs_ref1 in + UnionFind.set abs_ref_merged abs_id)) + abs_ids1) + bids) + abs_ids; + + log#ldebug + (lazy + ("reduce_ctx:\n\n- fixed_ids:\n" ^ show_ids_sets old_ids + ^ "\n\n- after reduce:\n" + ^ eval_ctx_to_string ~span:(Some span) !ctx + ^ "\n\n")); + + (* Reorder the loans and borrows in the fresh abstractions *) + let ctx = reorder_loans_borrows_in_fresh_abs span old_ids.aids !ctx in + + log#ldebug + (lazy + ("reduce_ctx:\n\n- fixed_ids:\n" ^ show_ids_sets old_ids + ^ "\n\n- after reduce and reorder borrows/loans:\n" + ^ eval_ctx_to_string ~span:(Some span) ctx + ^ "\n\n")); + + (* Return the new context *) + ctx + +(* TODO Adapt and comment *) let collapse_ctx (span : Meta.span) (loop_id : LoopId.id) (merge_funs : merge_duplicates_funcs option) (old_ids : ids_sets) (ctx0 : eval_ctx) : eval_ctx = @@ -523,9 +688,10 @@ let join_ctxs (span : Meta.span) (loop_id : LoopId.id) (fixed_ids : ids_sets) | x -> x in - let env0 = List.map (add_marker PLeft) env0 in - let env1 = List.map (add_marker PRight) env1 in - + (* TODO: Readd this + let env0 = List.map (add_marker PLeft) env0 in + let env1 = List.map (add_marker PRight) env1 in + *) List.iter check_valid env0; List.iter check_valid env1; (* Concatenate the suffixes and append the abstractions introduced while @@ -776,11 +942,11 @@ let loop_join_origin_with_continue_ctxs (config : config) (span : Meta.span) ("loop_join_origin_with_continue_ctxs:join_one: after destructure:\n" ^ eval_ctx_to_string ~span:(Some span) ctx)); - (* Collapse the context we want to add to the join *) - let ctx = collapse_ctx span loop_id None fixed_ids ctx in + (* Reduce the context we want to add to the join *) + let ctx = reduce_ctx span loop_id None fixed_ids ctx in log#ldebug (lazy - ("loop_join_origin_with_continue_ctxs:join_one: after collapse:\n" + ("loop_join_origin_with_continue_ctxs:join_one: after reduce:\n" ^ eval_ctx_to_string ~span:(Some span) ctx)); (* Refresh the fresh abstractions *) @@ -793,15 +959,20 @@ let loop_join_origin_with_continue_ctxs (config : config) (span : Meta.span) ("loop_join_origin_with_continue_ctxs:join_one: after join:\n" ^ eval_ctx_to_string ~span:(Some span) ctx1)); - (* Collapse again - the join might have introduce abstractions we want - to merge with the others (note that those abstractions may actually - lead to borrows/loans duplications) *) + (* Collapse to eliminate the markers *) joined_ctx := collapse_ctx_with_merge span loop_id fixed_ids !joined_ctx; log#ldebug (lazy ("loop_join_origin_with_continue_ctxs:join_one: after join-collapse:\n" ^ eval_ctx_to_string ~span:(Some span) !joined_ctx)); + (* Reduce again to reach fixed point *) + joined_ctx := reduce_ctx span loop_id None fixed_ids !joined_ctx; + log#ldebug + (lazy + ("loop_join_origin_with_continue_ctxs:join_one: after last reduce:\n" + ^ eval_ctx_to_string ~span:(Some span) !joined_ctx)); + (* Sanity check *) if !Config.sanity_checks then Invariants.check_invariants span !joined_ctx; (* Return *) |