Clarify the types used for static jump/catch (ocaml-flambda#1180)

backend/cmm.ml

@@ -107,11 +107,8 @@ type float_comparison = Lambda.float_comparison =
 let negate_float_comparison = Lambda.negate_float_comparison
 
 let swap_float_comparison = Lambda.swap_float_comparison
-type label = int
 
-type exit_label =
-  | Return_lbl
-  | Lbl of label
+type label = int
 
 let init_label = 99
 
@@ -128,6 +125,12 @@ let cur_label () = !label_counter
 
 let new_label() = incr label_counter; !label_counter
 
+type static_label = Lambda.static_label
+
+type exit_label =
+  | Return_lbl
+  | Lbl of static_label
+
 type rec_flag = Nonrecursive | Recursive
 
 type prefetch_temporal_locality_hint = Nonlocal | Low | Moderate | High
@@ -242,7 +245,7 @@ type expression =
       * Debuginfo.t * value_kind
   | Ccatch of
       rec_flag
-        * (label * (Backend_var.With_provenance.t * machtype) list
+        * (static_label * (Backend_var.With_provenance.t * machtype) list
           * expression * Debuginfo.t) list
         * expression * value_kind
   | Cexit of exit_label * expression list * trap_action list

backend/cmm.mli

@@ -98,7 +98,7 @@ val cur_label: unit -> label
 
 type exit_label =
   | Return_lbl
-  | Lbl of label
+  | Lbl of Lambda.static_label
 
 type rec_flag = Nonrecursive | Recursive
 
@@ -138,7 +138,7 @@ type phantom_defining_expr =
   (** The phantom-let-bound variable points at a block with the given
       structure. *)
 
-type trywith_shared_label = int (* Same as Ccatch handlers *)
+type trywith_shared_label = Lambda.static_label (* Same as Ccatch handlers *)
 
 type trap_action =
   | Push of trywith_shared_label
@@ -250,7 +250,7 @@ type expression =
       * Debuginfo.t * value_kind
   | Ccatch of
       rec_flag
-        * (label * (Backend_var.With_provenance.t * machtype) list
+        * (Lambda.static_label * (Backend_var.With_provenance.t * machtype) list
           * expression * Debuginfo.t) list
         * expression
         * value_kind

backend/cmm_helpers.mli

@@ -994,14 +994,18 @@ type static_handler
     binding variables [vars] in [body]. *)
 val handler :
   dbg:Debuginfo.t ->
-  int ->
+  Lambda.static_label ->
   (Backend_var.With_provenance.t * Cmm.machtype) list ->
   Cmm.expression ->
   static_handler
 
 (** [cexit id args] creates the cmm expression for static to a static handler
     with exit number [id], with arguments [args]. *)
-val cexit : int -> Cmm.expression list -> Cmm.trap_action list -> Cmm.expression
+val cexit :
+  Lambda.static_label ->
+  Cmm.expression list ->
+  Cmm.trap_action list ->
+  Cmm.expression
 
 (** [trap_return res traps] creates the cmm expression for returning [res] after
     applying the trap actions in [traps]. *)

middle_end/flambda2/to_cmm/to_cmm_env.ml

@@ -28,7 +28,7 @@ type expr_with_info =
 
 type cont =
   | Jump of
-      { cont : Cmm.label;
+      { cont : Lambda.static_label;
         param_types : Cmm.machtype list
       }
   | Inline of
@@ -317,10 +317,8 @@ let get_continuation env k =
       Continuation.print k
   | res -> res
 
-let new_cmm_continuation = Lambda.next_raise_count
-
 let add_jump_cont env k ~param_types =
-  let cont = new_cmm_continuation () in
+  let cont = Lambda.next_raise_count () in
   let conts = Continuation.Map.add k (Jump { param_types; cont }) env.conts in
   cont, { env with conts }
 

middle_end/flambda2/to_cmm/to_cmm_env.mli

@@ -280,7 +280,7 @@ val extra_info : t -> Simple.t -> extra_info option
     label), or inlined at any unique use site. *)
 type cont = private
   | Jump of
-      { cont : Cmm.label;
+      { cont : Lambda.static_label;
         param_types : Cmm.machtype list
       }
   | Inline of
@@ -292,7 +292,10 @@ type cont = private
 (** Record that the given continuation should be compiled to a jump, creating a
     fresh Cmm continuation identifier for it. *)
 val add_jump_cont :
-  t -> Continuation.t -> param_types:Cmm.machtype list -> Cmm.label * t
+  t ->
+  Continuation.t ->
+  param_types:Cmm.machtype list ->
+  Lambda.static_label * t
 
 (** Record that the given continuation should be inlined. *)
 val add_inline_cont :
@@ -327,4 +330,4 @@ val get_continuation : t -> Continuation.t -> cont
 (** Returns the Cmm continuation identifier bound to a continuation. Produces a
     fatal error if given an unbound continuation, or a continuation that was
     registered (using [add_inline_cont]) to be inlined. *)
-val get_cmm_continuation : t -> Continuation.t -> Cmm.label
+val get_cmm_continuation : t -> Continuation.t -> Lambda.static_label

ocaml/lambda/lambda.ml

@@ -434,6 +434,8 @@ let equal_meth_kind x y =
 
 type shared_code = (int * int) list
 
+type static_label = int
+
 type function_attribute = {
   inline : inline_attribute;
   specialise : specialise_attribute;
@@ -461,8 +463,8 @@ type lambda =
   | Lswitch of lambda * lambda_switch * scoped_location * layout
   | Lstringswitch of
       lambda * (string * lambda) list * lambda option * scoped_location * layout
-  | Lstaticraise of int * lambda list
-  | Lstaticcatch of lambda * (int * (Ident.t * layout) list) * lambda * layout
+  | Lstaticraise of static_label * lambda list
+  | Lstaticcatch of lambda * (static_label * (Ident.t * layout) list) * lambda * layout
   | Ltrywith of lambda * Ident.t * lambda * layout
   | Lifthenelse of lambda * lambda * lambda * layout
   | Lsequence of lambda * lambda

ocaml/lambda/lambda.mli

@@ -340,6 +340,8 @@ val equal_meth_kind : meth_kind -> meth_kind -> bool
 
 type shared_code = (int * int) list     (* stack size -> code label *)
 
+type static_label = int
+
 type function_attribute = {
   inline : inline_attribute;
   specialise : specialise_attribute;
@@ -369,8 +371,8 @@ type lambda =
    strings are pairwise distinct *)
   | Lstringswitch of
       lambda * (string * lambda) list * lambda option * scoped_location * layout
-  | Lstaticraise of int * lambda list
-  | Lstaticcatch of lambda * (int * (Ident.t * layout) list) * lambda * layout
+  | Lstaticraise of static_label * lambda list
+  | Lstaticcatch of lambda * (static_label * (Ident.t * layout) list) * lambda * layout
   | Ltrywith of lambda * Ident.t * lambda * layout
 (* Lifthenelse (e, t, f, layout) evaluates t if e evaluates to 0, and evaluates f if
    e evaluates to any other value; layout must be the layout of [t] and [f] *)
@@ -618,7 +620,7 @@ val primitive_may_allocate : primitive -> alloc_mode option
 (***********************)
 
 (* Get a new static failure ident *)
-val next_raise_count : unit -> int
+val next_raise_count : unit -> static_label
 
 val staticfail : lambda (* Anticipated static failure *)