Rename Undefined outcome to Choose

It is used for nondeterministic choice, so Undefined might be
misleading.

5 files changed, 51 insertions, 21 deletions

diff --git a/src/gen_lib/sail2_prompt.lem b/src/gen_lib/sail2_prompt.lem
index e01cc051..3cde7ade 100644
--- a/src/gen_lib/sail2_prompt.lem
+++ b/src/gen_lib/sail2_prompt.lem
@@ -38,6 +38,11 @@ end
 
 declare {isabelle} termination_argument foreachM = automatic
 
+val genlistM : forall 'a 'rv 'e. (nat -> monad 'rv 'a 'e) -> nat -> monad 'rv (list 'a) 'e
+let genlistM f n =
+  let indices = genlist (fun n -> n) n in
+  foreachM indices [] (fun n xs -> (f n >>= (fun x -> return (xs ++ [x]))))
+
 val and_boolM : forall 'rv 'e. monad 'rv bool 'e -> monad 'rv bool 'e -> monad 'rv bool 'e
 let and_boolM l r = l >>= (fun l -> if l then r else return false)
 
@@ -55,7 +60,7 @@ val bool_of_bitU_nondet : forall 'rv 'e. bitU -> monad 'rv bool 'e
 let bool_of_bitU_nondet = function
   | B0 -> return false
   | B1 -> return true
-  | BU -> undefined_bool ()
+  | BU -> choose_bool "bool_of_bitU"
 end
 
 val bools_of_bits_nondet : forall 'rv 'e. list bitU -> monad 'rv (list bool) 'e
@@ -93,16 +98,25 @@ let rec untilM vars cond body =
   cond vars >>= fun cond_val ->
   if cond_val then return vars else untilM vars cond body
 
-val internal_pick : forall 'rv 'a 'e. list 'a -> monad 'rv 'a 'e
-let internal_pick xs =
-  (* Use sufficiently many undefined bits and convert into an index into the list *)
-  bools_of_bits_nondet (repeat [BU] (length_list xs)) >>= fun bs ->
+val choose_bools : forall 'rv 'e. string -> nat -> monad 'rv (list bool) 'e
+let choose_bools descr n = genlistM (fun _ -> choose_bool descr) n
+
+val choose : forall 'rv 'a 'e. string -> list 'a -> monad 'rv 'a 'e
+let choose descr xs =
+  (* Use sufficiently many nondeterministically chosen bits and convert into an
+     index into the list *)
+  choose_bools descr (List.length xs) >>= fun bs ->
   let idx = (natFromNatural (nat_of_bools bs)) mod List.length xs in
   match index xs idx with
     | Just x -> return x
-    | Nothing -> Fail "internal_pick"
+    | Nothing -> Fail ("choose " ^ descr)
   end
 
+declare {isabelle} rename function choose = chooseM
+
+val internal_pick : forall 'rv 'a 'e. list 'a -> monad 'rv 'a 'e
+let internal_pick xs = choose "internal_pick" xs
+
 (*let write_two_regs r1 r2 vec =
   let is_inc =
     let is_inc_r1 = is_inc_of_reg r1 in
diff --git a/src/gen_lib/sail2_prompt_monad.lem b/src/gen_lib/sail2_prompt_monad.lem
index 079375a3..c6249d7a 100644
--- a/src/gen_lib/sail2_prompt_monad.lem
+++ b/src/gen_lib/sail2_prompt_monad.lem
@@ -29,8 +29,10 @@ type monad 'regval 'a 'e =
   | Read_reg of register_name * ('regval -> monad 'regval 'a 'e)
   (* Request to write register *)
   | Write_reg of register_name * 'regval * monad 'regval 'a 'e
-  (* Request to choose a Boolean, e.g. to resolve an undefined bit *)
-  | Undefined of (bool -> monad 'regval 'a 'e)
+  (* Request to choose a Boolean, e.g. to resolve an undefined bit. The string
+     argument may be used to provide information to the system about what the
+     Boolean is going to be used for. *)
+  | Choose of string * (bool -> monad 'regval 'a 'e)
   (* Print debugging or tracing information *)
   | Print of string * monad 'regval 'a 'e
   (*Result of a failed assert with possible error message to report*)
@@ -48,7 +50,7 @@ type event 'regval =
   | E_footprint
   | E_read_reg of register_name * 'regval
   | E_write_reg of register_name * 'regval
-  | E_undefined of bool
+  | E_choose of string * bool
   | E_print of string
 
 type trace 'regval = list (event 'regval)
@@ -64,7 +66,7 @@ let rec bind m f = match m with
   | Write_mem wk a sz v t k ->   Write_mem wk a sz v t   (fun v -> bind (k v) f)
   | Read_reg descr k ->          Read_reg descr          (fun v -> bind (k v) f)
   | Excl_res k ->                Excl_res                (fun v -> bind (k v) f)
-  | Undefined k ->               Undefined               (fun v -> bind (k v) f)
+  | Choose descr k ->            Choose descr            (fun v -> bind (k v) f)
   | Write_ea wk a sz k ->        Write_ea wk a sz        (bind k f)
   | Footprint k ->               Footprint               (bind k f)
   | Barrier bk k ->              Barrier bk              (bind k f)
@@ -77,8 +79,11 @@ end
 val exit : forall 'rv 'a 'e. unit -> monad 'rv 'a 'e
 let exit () = Fail "exit"
 
+val choose_bool : forall 'rv 'e. string -> monad 'rv bool 'e
+let choose_bool descr = Choose descr return
+
 val undefined_bool : forall 'rv 'e. unit -> monad 'rv bool 'e
-let undefined_bool () = Undefined return
+let undefined_bool () = choose_bool "undefined_bool"
 
 val assert_exp : forall 'rv 'e. bool -> string -> monad 'rv unit 'e
 let assert_exp exp msg = if exp then Done () else Fail msg
@@ -94,7 +99,7 @@ let rec try_catch m h = match m with
   | Write_mem wk a sz v t k ->   Write_mem wk a sz v t   (fun v -> try_catch (k v) h)
   | Read_reg descr k ->          Read_reg descr          (fun v -> try_catch (k v) h)
   | Excl_res k ->                Excl_res                (fun v -> try_catch (k v) h)
-  | Undefined k ->               Undefined               (fun v -> try_catch (k v) h)
+  | Choose descr k ->            Choose descr            (fun v -> try_catch (k v) h)
   | Write_ea wk a sz k ->        Write_ea wk a sz        (try_catch k h)
   | Footprint k ->               Footprint               (try_catch k h)
   | Barrier bk k ->              Barrier bk              (try_catch k h)
@@ -267,7 +272,7 @@ let emitEvent m e = match (e, m) with
   | (E_print m, Print m' k) ->
      if m' = m then Just k else Nothing
   | (E_excl_res v, Excl_res k) -> Just (k v)
-  | (E_undefined v, Undefined k) -> Just (k v)
+  | (E_choose descr v, Choose descr' k) -> if descr' = descr then Just (k v) else Nothing
   | (E_footprint, Footprint k) -> Just k
   | _ -> Nothing
 end
diff --git a/src/gen_lib/sail2_state.lem b/src/gen_lib/sail2_state.lem
index f703dead..ec787764 100644
--- a/src/gen_lib/sail2_state.lem
+++ b/src/gen_lib/sail2_state.lem
@@ -28,6 +28,11 @@ end
 
 declare {isabelle} termination_argument foreachS = automatic
 
+val genlistS : forall 'a 'rv 'e. (nat -> monadS 'rv 'a 'e) -> nat -> monadS 'rv (list 'a) 'e
+let genlistS f n =
+  let indices = genlist (fun n -> n) n in
+  foreachS indices [] (fun n xs -> (f n >>$= (fun x -> returnS (xs ++ [x]))))
+
 val and_boolS : forall 'rv 'e. monadS 'rv bool 'e -> monadS 'rv bool 'e -> monadS 'rv bool 'e
 let and_boolS l r = l >>$= (fun l -> if l then r else returnS false)
 
@@ -84,12 +89,17 @@ let rec untilS vars cond body s =
   (cond vars >>$= (fun cond_val s'' ->
   if cond_val then returnS vars s'' else untilS vars cond body s'')) s')) s
 
+val choose_boolsS : forall 'rv 'e. nat -> monadS 'rv (list bool) 'e
+let choose_boolsS n = genlistS (fun _ -> choose_boolS ()) n
+
+(* TODO: Replace by chooseS and prove equivalence to prompt monad version *)
 val internal_pickS : forall 'rv 'a 'e. list 'a -> monadS 'rv 'a 'e
 let internal_pickS xs =
-  (* Use sufficiently many undefined bits and convert into an index into the list *)
-  bools_of_bits_nondetS (repeat [BU] (length_list xs)) >>$= fun bs ->
+  (* Use sufficiently many nondeterministically chosen bits and convert into an
+     index into the list *)
+  choose_boolsS (List.length xs) >>$= fun bs ->
   let idx = (natFromNatural (nat_of_bools bs)) mod List.length xs in
   match index xs idx with
     | Just x -> returnS x
-    | Nothing -> failS "internal_pick"
+    | Nothing -> failS "choose internal_pick"
   end
diff --git a/src/gen_lib/sail2_state_lifting.lem b/src/gen_lib/sail2_state_lifting.lem
index 07a6215b..c227e89b 100644
--- a/src/gen_lib/sail2_state_lifting.lem
+++ b/src/gen_lib/sail2_state_lifting.lem
@@ -14,7 +14,7 @@ let rec liftState ra m = match m with
   | (Write_mem wk a sz v t k)   -> bindS (write_mem_bytesS wk a sz v t)   (fun v -> liftState ra (k v))
   | (Read_reg r k)              -> bindS (read_regvalS ra r)              (fun v -> liftState ra (k v))
   | (Excl_res k)                -> bindS (excl_resultS ())                (fun v -> liftState ra (k v))
-  | (Undefined k)               -> bindS (undefined_boolS ())             (fun v -> liftState ra (k v))
+  | (Choose _ k)                -> bindS (choose_boolS ())                (fun v -> liftState ra (k v))
   | (Write_reg r v k)           -> seqS (write_regvalS ra r v)            (liftState ra k)
   | (Write_ea _ _ _ k)          -> liftState ra k
   | (Footprint k)               -> liftState ra k
diff --git a/src/gen_lib/sail2_state_monad.lem b/src/gen_lib/sail2_state_monad.lem
index 8626052f..b2a7bb31 100644
--- a/src/gen_lib/sail2_state_monad.lem
+++ b/src/gen_lib/sail2_state_monad.lem
@@ -47,8 +47,8 @@ let seqS m n = bindS m (fun (_ : unit) -> n)
 let inline (>>$=) = bindS
 let inline (>>$) = seqS
 
-val chooseS : forall 'regs 'a 'e. SetType 'a => set 'a -> monadS 'regs 'a 'e
-let chooseS xs s = Set.map (fun x -> (Value x, s)) xs
+val chooseS : forall 'regs 'a 'e. SetType 'a => list 'a -> monadS 'regs 'a 'e
+let chooseS xs s = Set.fromList (List.map (fun x -> (Value x, s)) xs)
 
 val readS : forall 'regs 'a 'e. (sequential_state 'regs -> 'a) -> monadS 'regs 'a 'e
 let readS f = (fun s -> returnS (f s) s)
@@ -59,8 +59,9 @@ let updateS f = (fun s -> returnS () (f s))
 val failS : forall 'regs 'a 'e. string -> monadS 'regs 'a 'e
 let failS msg s = {(Ex (Failure msg), s)}
 
-val undefined_boolS : forall 'regval 'regs 'a 'e. unit -> monadS 'regs bool 'e
-let undefined_boolS () = chooseS {false; true}
+val choose_boolS : forall 'regval 'regs 'a 'e. unit -> monadS 'regs bool 'e
+let choose_boolS () = chooseS [false; true]
+let undefined_boolS = choose_boolS
 
 val exitS : forall 'regs 'e 'a. unit -> monadS 'regs 'a 'e
 let exitS () = failS "exit"