(**************************************************************************)
(*                                                                        *)
(*                                 OCaml                                  *)
(*                                                                        *)
(*             Xavier Leroy, projet Cristal, INRIA Rocquencourt           *)
(*                                                                        *)
(*   Copyright 1996 Institut National de Recherche en Informatique et     *)
(*     en Automatique.                                                    *)
(*                                                                        *)
(*   All rights reserved.  This file is distributed under the terms of    *)
(*   the GNU Lesser General Public License version 2.1, with the          *)
(*   special exception on linking described in the file LICENSE.          *)
(*                                                                        *)
(**************************************************************************)

(* The type of the instructions of the abstract machine *)

open Lambda

(* Structure of compilation environments *)

type compilation_env =
  { ce_stack: int Ident.tbl; (* Positions of variables in the stack *)
    ce_heap: int Ident.tbl;  (* Structure of the heap-allocated env *)
    ce_rec: int Ident.tbl }  (* Functions bound by the same let rec *)

(* The ce_stack component gives locations of variables residing
   in the stack. The locations are offsets w.r.t. the origin of the
   stack frame.
   The ce_heap component gives the positions of variables residing in the
   heap-allocated environment.
   The ce_rec component associates offsets to identifiers for functions
   bound by the same let rec as the current function.  The offsets
   are used by the OFFSETCLOSURE instruction to recover the closure
   pointer of the desired function from the env register (which
   points to the closure for the current function). *)

(* Debugging events *)

(* Warning: when you change these types, check runtime/backtrace_byt.c *)
type debug_event =
  { mutable ev_pos: int;                (* Position in bytecode *)
    ev_module: string;                  (* Name of defining module *)
    ev_loc: Location.t;                 (* Location in source file *)
    ev_kind: debug_event_kind;          (* Before/after event *)
    ev_defname: string;                 (* Enclosing definition *)
    ev_info: debug_event_info;          (* Extra information *)
    ev_typenv: Env.summary;             (* Typing environment *)
    ev_typsubst: Subst.t;               (* Substitution over types *)
    ev_compenv: compilation_env;        (* Compilation environment *)
    ev_stacksize: int;                  (* Size of stack frame *)
    ev_repr: debug_event_repr }         (* Position of the representative *)

and debug_event_kind =
    Event_before
  | Event_after of Types.type_expr
  | Event_pseudo

and debug_event_info =
    Event_function
  | Event_return of int
  | Event_other

and debug_event_repr =
    Event_none
  | Event_parent of int ref
  | Event_child of int ref

(* Abstract machine instructions *)

type label = int                        (* Symbolic code labels *)

type instruction =
    Klabel of label
  | Kacc of int
  | Kenvacc of int
  | Kpush
  | Kpop of int
  | Kassign of int
  | Kpush_retaddr of label
  | Kapply of int                       (* number of arguments *)
  | Kappterm of int * int               (* number of arguments, slot size *)
  | Kreturn of int                      (* slot size *)
  | Krestart
  | Kgrab of int                        (* number of arguments *)
  | Kclosure of label * int
  | Kclosurerec of label list * int
  | Koffsetclosure of int
  | Kgetglobal of Ident.t
  | Ksetglobal of Ident.t
  | Kconst of structured_constant
  | Kmakeblock of int * int             (* size, tag *)
  | Kmakefloatblock of int
  | Kgetfield of int
  | Ksetfield of int
  | Kgetfloatfield of int
  | Ksetfloatfield of int
  | Kvectlength
  | Kgetvectitem
  | Ksetvectitem
  | Kgetstringchar
  | Kgetbyteschar
  | Ksetbyteschar
  | Kbranch of label
  | Kbranchif of label
  | Kbranchifnot of label
  | Kstrictbranchif of label
  | Kstrictbranchifnot of label
  | Kswitch of label array * label array
  | Kboolnot
  | Kpushtrap of label
  | Kpoptrap
  | Kraise of raise_kind
  | Kcheck_signals
  | Kccall of string * int
  | Knegint | Kaddint | Ksubint | Kmulint | Kdivint | Kmodint
  | Kandint | Korint | Kxorint | Klslint | Klsrint | Kasrint
  | Kintcomp of integer_comparison
  | Koffsetint of int
  | Koffsetref of int
  | Kisint
  | Kisout
  | Kgetmethod
  | Kgetpubmet of int
  | Kgetdynmet
  | Kevent of debug_event
  | Kstop

val immed_min: int
val immed_max: int
