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open Utils
open Dcalc.Ast
module type Backend = sig
val init_backend : unit -> unit
type backend_context
val make_context : decl_ctx -> typ Pos.marked VarMap.t -> backend_context
type vc_encoding
val print_encoding : vc_encoding -> string
type model
type solver_result = ProvenTrue | ProvenFalse of model option | Unknown
val solve_vc_encoding : backend_context -> vc_encoding -> solver_result
val print_model : backend_context -> model -> string
val is_model_empty : model -> bool
val translate_expr :
backend_context -> Dcalc.Ast.expr Utils.Pos.marked -> backend_context * vc_encoding
end
module type BackendIO = sig
val init_backend : unit -> unit
type backend_context
val make_context : decl_ctx -> typ Pos.marked VarMap.t -> backend_context
type vc_encoding
val translate_expr :
backend_context -> Dcalc.Ast.expr Utils.Pos.marked -> backend_context * vc_encoding
type model
type vc_encoding_result = Success of vc_encoding * backend_context | Fail of string
val print_positive_result : Conditions.verification_condition -> string
val print_negative_result :
Conditions.verification_condition -> backend_context -> model option -> string
val encode_and_check_vc :
Dcalc.Ast.decl_ctx -> Conditions.verification_condition * vc_encoding_result -> unit
end
module MakeBackendIO (B : Backend) = struct
let init_backend = B.init_backend
type backend_context = B.backend_context
let make_context = B.make_context
type vc_encoding = B.vc_encoding
let translate_expr = B.translate_expr
type model = B.model
type vc_encoding_result = Success of B.vc_encoding * B.backend_context | Fail of string
let print_positive_result (vc : Conditions.verification_condition) : string =
match vc.Conditions.vc_kind with
| Conditions.NoEmptyError ->
Format.asprintf "%s This variable never returns an empty error"
(Cli.print_with_style [ ANSITerminal.yellow ] "[%s.%s]"
(Format.asprintf "%a" ScopeName.format_t vc.vc_scope)
(Bindlib.name_of (Pos.unmark vc.vc_variable)))
| Conditions.NoOverlappingExceptions ->
Format.asprintf "%s No two exceptions to ever overlap for this variable"
(Cli.print_with_style [ ANSITerminal.yellow ] "[%s.%s]"
(Format.asprintf "%a" ScopeName.format_t vc.vc_scope)
(Bindlib.name_of (Pos.unmark vc.vc_variable)))
let print_negative_result (vc : Conditions.verification_condition) (ctx : B.backend_context)
(model : B.model option) : string =
let var_and_pos =
match vc.Conditions.vc_kind with
| Conditions.NoEmptyError ->
Format.asprintf "%s This variable might return an empty error:\n%s"
(Cli.print_with_style [ ANSITerminal.yellow ] "[%s.%s]"
(Format.asprintf "%a" ScopeName.format_t vc.vc_scope)
(Bindlib.name_of (Pos.unmark vc.vc_variable)))
(Pos.retrieve_loc_text (Pos.get_position vc.vc_variable))
| Conditions.NoOverlappingExceptions ->
Format.asprintf "%s At least two exceptions overlap for this variable:\n%s"
(Cli.print_with_style [ ANSITerminal.yellow ] "[%s.%s]"
(Format.asprintf "%a" ScopeName.format_t vc.vc_scope)
(Bindlib.name_of (Pos.unmark vc.vc_variable)))
(Pos.retrieve_loc_text (Pos.get_position vc.vc_variable))
in
let counterexample : string option =
if !Cli.disable_counterexamples then
Some "Counterexample generation is disabled so none was generated."
else
match model with
| None ->
Some
"The solver did not manage to generate a counterexample to explain the faulty \
behavior."
| Some model ->
if B.is_model_empty model then None
else
Some
(Format.asprintf
"The solver generated the following counterexample to explain the faulty \
behavior:\n\
%s"
(B.print_model ctx model))
in
var_and_pos
^ match counterexample with None -> "" | Some counterexample -> "\n" ^ counterexample
(** [encode_and_check_vc] spawns a new Z3 solver and tries to solve the expression [vc] **)
let encode_and_check_vc (decl_ctx : decl_ctx)
(vc : Conditions.verification_condition * vc_encoding_result) : unit =
let vc, z3_vc = vc in
Cli.debug_print
(Format.asprintf "For this variable:\n%s\n"
(Pos.retrieve_loc_text (Pos.get_position vc.Conditions.vc_guard)));
Cli.debug_print
(Format.asprintf "This verification condition was generated for %s:@\n%a"
(Cli.print_with_style [ ANSITerminal.yellow ] "%s"
(match vc.vc_kind with
| Conditions.NoEmptyError -> "the variable definition never to return an empty error"
| NoOverlappingExceptions -> "no two exceptions to ever overlap"))
(Dcalc.Print.format_expr decl_ctx)
vc.vc_guard);
match z3_vc with
| Success (encoding, backend_ctx) -> (
Cli.debug_print
(Format.asprintf "The translation to Z3 is the following:@\n%s"
(B.print_encoding encoding));
match B.solve_vc_encoding backend_ctx encoding with
| ProvenTrue -> Cli.result_print (print_positive_result vc)
| ProvenFalse model -> Cli.error_print (print_negative_result vc backend_ctx model)
| Unknown -> failwith "The solver failed at proving or disproving the VC")
| Fail msg -> Cli.error_print (Format.asprintf "The translation to Z3 failed:@\n%s" msg)
end