(**************************************************************************)
(*                                                                        *)
(*                                 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.          *)
(*                                                                        *)
(**************************************************************************)

(* Disassembler for executable and .cmo object files *)

open Config
open Instruct
open Location
open Opcodes
open Opnames
open Cmo_format
open Printf

let print_banners = ref true
let print_locations = ref true
let print_reloc_info = ref false

(* Read signed and unsigned integers *)

let inputu ic =
  let b1 = input_byte ic in
  let b2 = input_byte ic in
  let b3 = input_byte ic in
  let b4 = input_byte ic in
  (b4 lsl 24) + (b3 lsl 16) + (b2 lsl 8) + b1

let inputs ic =
  let b1 = input_byte ic in
  let b2 = input_byte ic in
  let b3 = input_byte ic in
  let b4 = input_byte ic in
  let b4' = if b4 >= 128 then b4-256 else b4 in
  (b4' lsl 24) + (b3 lsl 16) + (b2 lsl 8) + b1

(* Global variables *)

type global_table_entry =
  | Glob of Symtable.Global.t
  | Constant of Obj.t

let start = ref 0                              (* Position of beg. of code *)
let reloc = ref ([] : (reloc_info * int) list) (* Relocation table *)
let globals = ref ([||] : global_table_entry array) (* Global map *)
let primitives = ref ([||] : string array)     (* Table of primitives *)
let objfile = ref false                        (* true if dumping a .cmo *)

(* Events (indexed by PC) *)

let event_table = (Hashtbl.create 253 : (int, debug_event) Hashtbl.t)

let relocate_event orig ev =
  ev.ev_pos <- orig + ev.ev_pos;
  match ev.ev_repr with
    Event_parent repr -> repr := ev.ev_pos
  | _                 -> ()

let record_events orig evl =
  List.iter
    (fun ev ->
      relocate_event orig ev;
      Hashtbl.add event_table ev.ev_pos ev)
    evl

(* Print an obj *)

let same_custom x y =
  Nativeint.equal (Obj.raw_field x 0) (Obj.raw_field (Obj.repr y) 0)

let rec print_obj x =
  if Obj.is_block x then begin
    let tag = Obj.tag x in
    if tag = Obj.string_tag then
        printf "%S" (Obj.magic x : string)
    else if tag = Obj.double_tag then
        printf "%.12g" (Obj.magic x : float)
    else if tag = Obj.double_array_tag then begin
        let a = (Obj.magic x : floatarray) in
        printf "[|";
        for i = 0 to Array.Floatarray.length a - 1 do
          if i > 0 then printf ", ";
          printf "%.12g" (Array.Floatarray.get a i)
        done;
        printf "|]"
    end else if tag = Obj.custom_tag && same_custom x 0l then
        printf "%ldl" (Obj.magic x : int32)
    else if tag = Obj.custom_tag && same_custom x 0n then
        printf "%ndn" (Obj.magic x : nativeint)
    else if tag = Obj.custom_tag && same_custom x 0L then
        printf "%LdL" (Obj.magic x : int64)
    else if tag < Obj.no_scan_tag then begin
        printf "<%d>" (Obj.tag x);
        match Obj.size x with
          0 -> ()
        | 1 ->
            printf "("; print_obj (Obj.field x 0); printf ")"
        | n ->
            printf "("; print_obj (Obj.field x 0);
            for i = 1 to n - 1 do
              printf ", "; print_obj (Obj.field x i)
            done;
            printf ")"
    end else
        printf "<tag %d>" tag
  end else
    printf "%d" (Obj.magic x : int)

(* Current position in input file *)

let currpos ic =
  pos_in ic - !start

(* Access in the relocation table *)

let rec rassoc key = function
    [] -> raise Not_found
  | (a,b) :: l -> if b = key then a else rassoc key l

let find_reloc ic =
  rassoc (pos_in ic - !start) !reloc

(* Symbolic printing of global names, etc *)

let print_unexpected_reloc reloc_constr reloc_arg =
  printf "<unexpected (%s '%s') reloc>" reloc_constr reloc_arg

let print_unexpected_reloc_literal sc =
  printf "<unexpected (Reloc_literal ";
  print_obj sc;
  printf ") reloc>"

let print_getglobal_name ic =
  if !objfile then begin
    begin try
      match find_reloc ic with
        | Reloc_getcompunit (Compunit cu_name) -> print_string cu_name
        | Reloc_getpredef (Predef_exn predef_exn) -> print_string predef_exn
        | Reloc_literal sc -> print_obj sc
        | Reloc_setcompunit (Compunit cu_name) ->
          print_unexpected_reloc "Reloc_setcompunit" cu_name
        | Reloc_primitive prim ->
          print_unexpected_reloc "Reloc_primitive" prim
    with Not_found ->
      print_string "<no reloc>"
    end;
    ignore (inputu ic);
  end
  else begin
    let n = inputu ic in
    if n >= Array.length !globals || n < 0
    then print_string "<global table overflow>"
    else match !globals.(n) with
         | Glob glob -> print_string
                       (Format.asprintf "%a" Symtable.Global.description glob)
         | Constant obj -> print_obj obj
  end

let print_setglobal_name ic =
  if !objfile then begin
    begin try
      match find_reloc ic with
      | Reloc_setcompunit (Compunit cu_name) -> print_string cu_name
      | Reloc_literal sc ->
        print_unexpected_reloc_literal sc
      | Reloc_getcompunit (Compunit cu_name) ->
        print_unexpected_reloc "Reloc_getcompunit" cu_name
      | Reloc_getpredef (Predef_exn predef_exn) ->
        print_unexpected_reloc "Reloc_getpredef" predef_exn
      | Reloc_primitive prim ->
        print_unexpected_reloc "Reloc_primitive" prim
    with Not_found ->
      print_string "<no reloc>"
    end;
    ignore (inputu ic);
  end
  else begin
    let n = inputu ic in
    if n >= Array.length !globals || n < 0
    then print_string "<global table overflow>"
    else match !globals.(n) with
         | Glob glob ->
             print_string
               (Format.asprintf "%a" Symtable.Global.description glob)
         | Constant _ -> print_string "<unexpected constant>"
  end

let print_primitive ic =
  if !objfile then begin
    begin try
      match find_reloc ic with
        Reloc_primitive s -> print_string s
      | Reloc_literal sc ->
        print_unexpected_reloc_literal sc
      | Reloc_getcompunit (Compunit cu_name) ->
          print_unexpected_reloc "Reloc_getcompunit" cu_name
      | Reloc_setcompunit (Compunit cu_name) ->
        print_unexpected_reloc "Reloc_setcompunit" cu_name
      | Reloc_getpredef (Predef_exn predef_exn) ->
        print_unexpected_reloc "Reloc_getpredef" predef_exn
    with Not_found ->
      print_string "<no reloc>"
    end;
    ignore (inputu ic);
  end
  else begin
    let n = inputu ic in
    if n >= Array.length !primitives || n < 0
    then print_int n
    else print_string !primitives.(n)
  end

(* Disassemble one instruction *)

let currpc ic =
  currpos ic / 4

type shape =
  | Nothing
  | Uint
  | Sint
  | Uint_Uint
  | Disp
  | Uint_Disp
  | Sint_Disp
  | Getglobal
  | Getglobal_Uint
  | Setglobal
  | Primitive
  | Uint_Primitive
  | Switch
  | Closurerec
  | Pubmet

let op_shapes = [
  opACC0, Nothing;
  opACC1, Nothing;
  opACC2, Nothing;
  opACC3, Nothing;
  opACC4, Nothing;
  opACC5, Nothing;
  opACC6, Nothing;
  opACC7, Nothing;
  opACC, Uint;
  opPUSH, Nothing;
  opPUSHACC0, Nothing;
  opPUSHACC1, Nothing;
  opPUSHACC2, Nothing;
  opPUSHACC3, Nothing;
  opPUSHACC4, Nothing;
  opPUSHACC5, Nothing;
  opPUSHACC6, Nothing;
  opPUSHACC7, Nothing;
  opPUSHACC, Uint;
  opPOP, Uint;
  opASSIGN, Uint;
  opENVACC1, Nothing;
  opENVACC2, Nothing;
  opENVACC3, Nothing;
  opENVACC4, Nothing;
  opENVACC, Uint;
  opPUSHENVACC1, Nothing;
  opPUSHENVACC2, Nothing;
  opPUSHENVACC3, Nothing;
  opPUSHENVACC4, Nothing;
  opPUSHENVACC, Uint;
  opPUSH_RETADDR, Disp;
  opAPPLY, Uint;
  opAPPLY1, Nothing;
  opAPPLY2, Nothing;
  opAPPLY3, Nothing;
  opAPPTERM, Uint_Uint;
  opAPPTERM1, Uint;
  opAPPTERM2, Uint;
  opAPPTERM3, Uint;
  opRETURN, Uint;
  opRESTART, Nothing;
  opGRAB, Uint;
  opCLOSURE, Uint_Disp;
  opCLOSUREREC, Closurerec;
  opOFFSETCLOSUREM3, Nothing;
  opOFFSETCLOSURE0, Nothing;
  opOFFSETCLOSURE3, Nothing;
  opOFFSETCLOSURE, Sint;  (* was Uint *)
  opPUSHOFFSETCLOSUREM3, Nothing;
  opPUSHOFFSETCLOSURE0, Nothing;
  opPUSHOFFSETCLOSURE3, Nothing;
  opPUSHOFFSETCLOSURE, Sint; (* was Nothing *)
  opGETGLOBAL, Getglobal;
  opPUSHGETGLOBAL, Getglobal;
  opGETGLOBALFIELD, Getglobal_Uint;
  opPUSHGETGLOBALFIELD, Getglobal_Uint;
  opSETGLOBAL, Setglobal;
  opATOM0, Nothing;
  opATOM, Uint;
  opPUSHATOM0, Nothing;
  opPUSHATOM, Uint;
  opMAKEBLOCK, Uint_Uint;
  opMAKEBLOCK1, Uint;
  opMAKEBLOCK2, Uint;
  opMAKEBLOCK3, Uint;
  opMAKEFLOATBLOCK, Uint;
  opGETFIELD0, Nothing;
  opGETFIELD1, Nothing;
  opGETFIELD2, Nothing;
  opGETFIELD3, Nothing;
  opGETFIELD, Uint;
  opGETFLOATFIELD, Uint;
  opSETFIELD0, Nothing;
  opSETFIELD1, Nothing;
  opSETFIELD2, Nothing;
  opSETFIELD3, Nothing;
  opSETFIELD, Uint;
  opSETFLOATFIELD, Uint;
  opVECTLENGTH, Nothing;
  opGETVECTITEM, Nothing;
  opSETVECTITEM, Nothing;
  opGETSTRINGCHAR, Nothing;
  opGETBYTESCHAR, Nothing;
  opSETBYTESCHAR, Nothing;
  opBRANCH, Disp;
  opBRANCHIF, Disp;
  opBRANCHIFNOT, Disp;
  opSWITCH, Switch;
  opBOOLNOT, Nothing;
  opPUSHTRAP, Disp;
  opPOPTRAP, Nothing;
  opRAISE, Nothing;
  opCHECK_SIGNALS, Nothing;
  opC_CALL1, Primitive;
  opC_CALL2, Primitive;
  opC_CALL3, Primitive;
  opC_CALL4, Primitive;
  opC_CALL5, Primitive;
  opC_CALLN, Uint_Primitive;
  opCONST0, Nothing;
  opCONST1, Nothing;
  opCONST2, Nothing;
  opCONST3, Nothing;
  opCONSTINT, Sint;
  opPUSHCONST0, Nothing;
  opPUSHCONST1, Nothing;
  opPUSHCONST2, Nothing;
  opPUSHCONST3, Nothing;
  opPUSHCONSTINT, Sint;
  opNEGINT, Nothing;
  opADDINT, Nothing;
  opSUBINT, Nothing;
  opMULINT, Nothing;
  opDIVINT, Nothing;
  opMODINT, Nothing;
  opANDINT, Nothing;
  opORINT, Nothing;
  opXORINT, Nothing;
  opLSLINT, Nothing;
  opLSRINT, Nothing;
  opASRINT, Nothing;
  opEQ, Nothing;
  opNEQ, Nothing;
  opLTINT, Nothing;
  opLEINT, Nothing;
  opGTINT, Nothing;
  opGEINT, Nothing;
  opOFFSETINT, Sint;
  opOFFSETREF, Sint;
  opISINT, Nothing;
  opGETMETHOD, Nothing;
  opGETDYNMET, Nothing;
  opGETPUBMET, Pubmet;
  opBEQ, Sint_Disp;
  opBNEQ, Sint_Disp;
  opBLTINT, Sint_Disp;
  opBLEINT, Sint_Disp;
  opBGTINT, Sint_Disp;
  opBGEINT, Sint_Disp;
  opULTINT, Nothing;
  opUGEINT, Nothing;
  opBULTINT, Uint_Disp;
  opBUGEINT, Uint_Disp;
  opPERFORM, Nothing;
  opRESUME, Nothing;
  opRESUMETERM, Uint;
  opREPERFORMTERM, Uint;
  opSTOP, Nothing;
  opEVENT, Nothing;
  opBREAK, Nothing;
  opRERAISE, Nothing;
  opRAISE_NOTRACE, Nothing;
]

let print_event ev =
  if !print_locations then
    let ls = ev.ev_loc.loc_start in
    let le = ev.ev_loc.loc_end in
    printf "File \"%s\", line %d, characters %d-%d:\n" ls.Lexing.pos_fname
      ls.Lexing.pos_lnum (ls.Lexing.pos_cnum - ls.Lexing.pos_bol)
      (le.Lexing.pos_cnum - ls.Lexing.pos_bol)

let print_instr ic =
  let pos = currpos ic in
  List.iter print_event (Hashtbl.find_all event_table pos);
  printf "%8d  " (pos / 4);
  let op = inputu ic in
  if op >= Array.length names_of_instructions || op < 0
  then (print_string "*** unknown opcode : "; print_int op)
  else print_string names_of_instructions.(op);
  begin try
    let shape = List.assoc op op_shapes in
    if shape <> Nothing && shape <> Switch then print_string " ";
    match shape with
    | Uint -> print_int (inputu ic)
    | Sint -> print_int (inputs ic)
    | Uint_Uint
       -> print_int (inputu ic); print_string ", "; print_int (inputu ic)
    | Disp -> let p = currpc ic in print_int (p + inputs ic)
    | Uint_Disp
       -> print_int (inputu ic); print_string ", ";
          let p = currpc ic in print_int (p + inputs ic)
    | Sint_Disp
       -> print_int (inputs ic); print_string ", ";
          let p = currpc ic in print_int (p + inputs ic)
    | Getglobal -> print_getglobal_name ic
    | Getglobal_Uint
       -> print_getglobal_name ic; print_string ", "; print_int (inputu ic)
    | Setglobal -> print_setglobal_name ic
    | Primitive -> print_primitive ic
    | Uint_Primitive
       -> print_int(inputu ic); print_string ", "; print_primitive ic
    | Switch
       -> let n = inputu ic in
          let orig = currpc ic in
          for i = 0 to (n land 0xFFFF) - 1 do
            print_string "\n        int "; print_int i; print_string " -> ";
            print_int(orig + inputs ic);
          done;
          for i = 0 to (n lsr 16) - 1 do
            print_string "\n        tag "; print_int i; print_string " -> ";
            print_int(orig + inputs ic);
          done;
    | Closurerec
       -> let nfuncs = inputu ic in
          let nvars = inputu ic in
          let orig = currpc ic in
          print_int nvars;
          for _i = 0 to nfuncs - 1 do
            print_string ", ";
            print_int (orig + inputs ic);
          done;
    | Pubmet
       -> let tag = inputs ic in
          let _cache = inputu ic in
          print_int tag
    | Nothing -> ()
  with Not_found -> print_string " (unknown arguments)"
  end;
  print_string "\n"

(* Disassemble a block of code *)

let print_code ic len =
  start := pos_in ic;
  let stop = !start + len in
  while pos_in ic < stop do print_instr ic done

(* Dump relocation info *)

let print_reloc (info, pos) =
  printf "    %d    (%d)    " pos (pos/4);
  match info with
  | Reloc_literal sc -> print_obj sc; printf "\n"
  | Reloc_getcompunit (Compunit cu_name) ->
    printf "require        %s\n" cu_name
  | Reloc_getpredef (Predef_exn predef_exn) ->
    printf "require predef %s\n" predef_exn
  | Reloc_setcompunit (Compunit cu_name) ->
    printf "provide        %s\n" cu_name
  | Reloc_primitive s ->
    printf "prim           %s\n" s

(* Print a .cmo file *)

let dump_obj ic =
  let buffer = really_input_string ic (String.length cmo_magic_number) in
  if buffer <> cmo_magic_number then begin
    prerr_endline "Not an object file"; exit 2
  end;
  let cu_pos = input_binary_int ic in
  seek_in ic cu_pos;
  let cu = (input_value ic : compilation_unit) in
  reloc := cu.cu_reloc;
  if !print_reloc_info then
    List.iter print_reloc cu.cu_reloc;
  if cu.cu_debug > 0 then begin
    seek_in ic cu.cu_debug;
    let evl = (Compression.input_value ic : debug_event list) in
    ignore (Compression.input_value ic);
                (* Skip the list of absolute directory names *)
    record_events 0 evl
  end;
  seek_in ic cu.cu_pos;
  print_code ic cu.cu_codesize

(* Print an executable file *)

let dump_exe ic =
  let toc = Bytesections.read_toc ic in
(* Read the primitive table from an executable *)
  let prims = Bytesections.read_section_string toc ic Bytesections.Name.PRIM in
  primitives := Array.of_list (Misc.split_null_terminated prims);
  let init_data : Obj.t array =
    Bytesections.read_section_struct toc ic Bytesections.Name.DATA in
  globals := Array.map (fun x -> Constant x) init_data;
  let sym_table : Symtable.global_map =
    Bytesections.read_section_struct toc ic Bytesections.Name.SYMB in
  Symtable.iter_global_map
    (fun global pos -> !globals.(pos) <- Glob global) sym_table;
  begin
    match Bytesections.seek_section toc ic Bytesections.Name.DBUG with
    | exception Not_found -> ()
    | (_ : int) ->
        let num_eventlists = input_binary_int ic in
        for _i = 1 to num_eventlists do
          let orig = input_binary_int ic in
          let evl = (Compression.input_value ic : debug_event list) in
          (* Skip the list of absolute directory names *)
          ignore (Compression.input_value ic);
          record_events orig evl
        done
  end;
  let code_size = Bytesections.seek_section toc ic Bytesections.Name.CODE in
  print_code ic code_size

let arg_list = [
  "-nobanners", Arg.Clear print_banners, " : don't print banners";
  "-noloc", Arg.Clear print_locations, " : don't print source information";
  "-reloc", Arg.Set print_reloc_info, " : print relocation information";
  "-args", Arg.Expand Arg.read_arg,
     "<file> Read additional newline separated command line arguments \n\
     \      from <file>";
  "-args0", Arg.Expand Arg.read_arg0,
     "<file> Read additional NUL separated command line arguments from \n\
     \      <file>";
]
let arg_usage =
  Printf.sprintf "%s [OPTIONS] FILES : dump content of bytecode files"
                 Sys.argv.(0)

let first_file = ref true

let arg_fun filename =
  let ic = open_in_bin filename in
  if not !first_file then print_newline ();
  first_file := false;
  if !print_banners then printf "## start of ocaml dump of %S\n%!" filename;
  begin try
          objfile := false; dump_exe ic
    with Bytesections.Bad_magic_number ->
      objfile := true; seek_in ic 0; dump_obj ic
  end;
  close_in ic;
  if !print_banners then printf "## end of ocaml dump of %S\n%!" filename

let main () =
  Arg.parse_expand arg_list arg_fun arg_usage;
    exit 0

let _ = main ()
