summaryrefslogtreecommitdiff
path: root/bytecomp/symtable.ml
blob: bad39a2135524c3cfa33fef76a5b8a80f07e8588 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
(***********************************************************************)
(*                                                                     *)
(*                           Objective Caml                            *)
(*                                                                     *)
(*            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 Q Public License version 1.0.               *)
(*                                                                     *)
(***********************************************************************)

(* $Id$ *)

(* To assign numbers to globals and primitives *)

open Misc
open Asttypes
open Lambda
open Cmo_format

(* Functions for batch linking *)

type error =
    Undefined_global of string
  | Unavailable_primitive of string
  | Wrong_vm of string
  | Uninitialized_global of string

exception Error of error

(* Tables for numbering objects *)

type 'a numtable =
  { num_cnt: int;               (* The next number *)
    num_tbl: ('a, int) Tbl.t }  (* The table of already numbered objects *)

let empty_numtable = { num_cnt = 0; num_tbl = Tbl.empty }

let find_numtable nt key =
  Tbl.find key nt.num_tbl

let enter_numtable nt key =
  let n = !nt.num_cnt in
  nt := { num_cnt = n + 1; num_tbl = Tbl.add key n !nt.num_tbl };
  n

let incr_numtable nt =
  let n = !nt.num_cnt in
  nt := { num_cnt = n + 1; num_tbl = !nt.num_tbl };
  n

(* Global variables *)

let global_table = ref(empty_numtable : Ident.t numtable)
and literal_table = ref([] : (int * structured_constant) list)

let slot_for_getglobal id =
  try
    find_numtable !global_table id
  with Not_found ->
    raise(Error(Undefined_global(Ident.name id)))

let slot_for_setglobal id =
  enter_numtable global_table id

let slot_for_literal cst =
  let n = incr_numtable global_table in
  literal_table := (n, cst) :: !literal_table;
  n

(* The C primitives *)

let c_prim_table = ref(empty_numtable : string numtable)

let set_prim_table name =
  ignore(enter_numtable c_prim_table name)

let num_of_prim name =
  try
    find_numtable !c_prim_table name
  with Not_found ->
    if !Clflags.custom_runtime then
      enter_numtable c_prim_table name
    else begin
      let symb =
        try Dll.find_primitive name
        with Not_found -> raise(Error(Unavailable_primitive name)) in
      let num = enter_numtable c_prim_table name in
      Dll.synchronize_primitive num symb;
      num
    end

let require_primitive name =
  if name.[0] <> '%' then ignore(num_of_prim name)

let all_primitives () =
  let prim = Array.create !c_prim_table.num_cnt "" in
  Tbl.iter (fun name number -> prim.(number) <- name) !c_prim_table.num_tbl;
  prim

let data_primitive_names () =
  let prim = all_primitives() in
  let b = Buffer.create 512 in
  for i = 0 to Array.length prim - 1 do
    Buffer.add_string b prim.(i); Buffer.add_char b '\000'
  done;
  Buffer.contents b

let output_primitive_names outchan =
  output_string outchan (data_primitive_names())

open Printf

let output_primitive_table outchan =
  let prim = all_primitives() in
  for i = 0 to Array.length prim - 1 do
    fprintf outchan "extern value %s();\n" prim.(i)
  done;
  fprintf outchan "typedef value (*primitive)();\n";
  fprintf outchan "primitive caml_builtin_cprim[] = {\n";
  for i = 0 to Array.length prim - 1 do
    fprintf outchan "  %s,\n" prim.(i)
  done;
  fprintf outchan "  (primitive) 0 };\n";
  fprintf outchan "char * caml_names_of_builtin_cprim[] = {\n";
  for i = 0 to Array.length prim - 1 do
    fprintf outchan "  \"%s\",\n" prim.(i)
  done;
  fprintf outchan "  (char *) 0 };\n"

(* Initialization for batch linking *)

let init () =
  (* Enter the predefined exceptions *)
  Array.iter 
    (fun name -> 
      let id =
        try List.assoc name Predef.builtin_values
        with Not_found -> fatal_error "Symtable.init" in
      let c = slot_for_setglobal id in
      let cst = Const_block(0, [Const_base(Const_string name)]) in
      literal_table := (c, cst) :: !literal_table)
    Runtimedef.builtin_exceptions;
  (* Initialize the known C primitives *)
  if String.length !Clflags.use_prims > 0 then begin
      let ic = open_in !Clflags.use_prims in
      try
        while true do
          set_prim_table (input_line ic)
        done
      with End_of_file -> close_in ic
         | x -> close_in ic; raise x
  end else if String.length !Clflags.use_runtime > 0 then begin
    let primfile = Filename.temp_file "camlprims" "" in
    try
      if Sys.command(Printf.sprintf "%s -p > %s"
                                    !Clflags.use_runtime primfile) <> 0
      then raise(Error(Wrong_vm !Clflags.use_runtime));
      let ic = open_in primfile in
      try
        while true do
          set_prim_table (input_line ic)
        done
      with End_of_file -> close_in ic; remove_file primfile
         | x -> close_in ic; raise x
    with x -> remove_file primfile; raise x
  end else begin
    Array.iter set_prim_table Runtimedef.builtin_primitives
  end

(* Relocate a block of object bytecode *)

(* Must use the unsafe String.set here because the block may be
   a "fake" string as returned by Meta.static_alloc. *)

let patch_int buff pos n =
  String.unsafe_set buff pos (Char.unsafe_chr n);
  String.unsafe_set buff (pos + 1) (Char.unsafe_chr (n asr 8));
  String.unsafe_set buff (pos + 2) (Char.unsafe_chr (n asr 16));
  String.unsafe_set buff (pos + 3) (Char.unsafe_chr (n asr 24))

let patch_object buff patchlist = 
  List.iter
    (function
        (Reloc_literal sc, pos) ->
          patch_int buff pos (slot_for_literal sc)
      | (Reloc_getglobal id, pos) ->
          patch_int buff pos (slot_for_getglobal id)
      | (Reloc_setglobal id, pos) ->
          patch_int buff pos (slot_for_setglobal id)
      | (Reloc_primitive name, pos) ->
          patch_int buff pos (num_of_prim name))
    patchlist

(* Translate structured constants *)

let rec transl_const = function
    Const_base(Const_int i) -> Obj.repr i
  | Const_base(Const_char c) -> Obj.repr c
  | Const_base(Const_string s) -> Obj.repr s
  | Const_base(Const_float f) -> Obj.repr (float_of_string f)
  | Const_base(Const_int32 i) -> Obj.repr i
  | Const_base(Const_int64 i) -> Obj.repr i
  | Const_base(Const_nativeint i) -> Obj.repr i
  | Const_pointer i -> Obj.repr i
  | Const_immstring s -> Obj.repr s
  | Const_block(tag, fields) ->
      let block = Obj.new_block tag (List.length fields) in
      let pos = ref 0 in
      List.iter
        (fun c -> Obj.set_field block !pos (transl_const c); incr pos)
        fields;
      block
  | Const_float_array fields ->
      Obj.repr(Array.of_list(List.map (fun f -> float_of_string f) fields))

(* Build the initial table of globals *)

let initial_global_table () =
  let glob = Array.create !global_table.num_cnt (Obj.repr 0) in
  List.iter
    (fun (slot, cst) -> glob.(slot) <- transl_const cst)
    !literal_table;
  literal_table := [];
  glob

(* Save the table of globals *)

let output_global_map oc =
  output_value oc !global_table

let data_global_map () =
  Obj.repr !global_table

(* Functions for toplevel use *)

(* Update the in-core table of globals *)

let update_global_table () =
  let ng = !global_table.num_cnt in
  if ng > Array.length(Meta.global_data()) then Meta.realloc_global_data ng;
  let glob = Meta.global_data() in
  List.iter
    (fun (slot, cst) -> glob.(slot) <- transl_const cst)
    !literal_table;
  literal_table := []

(* Recover data for toplevel initialization.  Data can come either from
   executable file (normal case) or from linked-in data (-output-obj). *)

type section_reader = { 
  read_string: string -> string;
  read_struct: string -> Obj.t;
  close_reader: unit -> unit
}

let read_sections () =
  try
    let sections = Meta.get_section_table () in
    { read_string =
        (fun name -> (Obj.magic(List.assoc name sections) : string));
      read_struct =
        (fun name -> List.assoc name sections);
      close_reader = 
        (fun () -> ()) }
  with Not_found ->
    let ic = open_in_bin Sys.executable_name in
    Bytesections.read_toc ic;
    { read_string = Bytesections.read_section_string ic;
      read_struct = Bytesections.read_section_struct ic;
      close_reader = fun () -> close_in ic }

(* Initialize the linker for toplevel use *)

let init_toplevel () =
  try
    let sect = read_sections () in
    (* Locations of globals *)
    global_table := (Obj.magic (sect.read_struct "SYMB") : Ident.t numtable);
    (* Primitives *)
    let prims = sect.read_string "PRIM" in
    c_prim_table := empty_numtable;
    let pos = ref 0 in
    while !pos < String.length prims do
      let i = String.index_from prims !pos '\000' in
      set_prim_table (String.sub prims !pos (i - !pos));
      pos := i + 1
    done;
    (* DLL initialization *)
    let dllpath = try sect.read_string "DLPT" with Not_found -> "" in
    Dll.init_toplevel dllpath;
    (* Recover CRC infos for interfaces *)
    let crcintfs =
      try (Obj.magic (sect.read_struct "CRCS") : (string * Digest.t) list)
      with Not_found -> [] in
    (* Done *)
    sect.close_reader();
    crcintfs
  with Bytesections.Bad_magic_number | Not_found | Failure _ ->
    fatal_error "Toplevel bytecode executable is corrupted"

(* Find the value of a global identifier *)

let get_global_position id = slot_for_getglobal id

let get_global_value id =
  (Meta.global_data()).(slot_for_getglobal id)
let assign_global_value id v =
  (Meta.global_data()).(slot_for_getglobal id) <- v

(* Check that all globals referenced in the given patch list
   have been initialized already *)

let check_global_initialized patchlist =
  (* First determine the globals we will define *)
  let defined_globals =
    List.fold_left
      (fun accu rel ->
        match rel with
          (Reloc_setglobal id, pos) -> id :: accu
        | _ -> accu)
      [] patchlist in
  (* Then check that all referenced, not defined globals have a value *)
  let check_reference = function
      (Reloc_getglobal id, pos) ->
        if not (List.mem id defined_globals)
        && Obj.is_int (get_global_value id)
        then raise (Error(Uninitialized_global(Ident.name id)))
    | _ -> () in
  List.iter check_reference patchlist

(* Save and restore the current state *)

type global_map = Ident.t numtable

let current_state () = !global_table

let restore_state st = global_table := st

let hide_additions st =
  if st.num_cnt > !global_table.num_cnt then
    fatal_error "Symtable.hide_additions";
  global_table :=
    { num_cnt = !global_table.num_cnt;
      num_tbl = st.num_tbl }

(* "Filter" the global map according to some predicate.
   Used to expunge the global map for the toplevel. *)

let filter_global_map p gmap =
  let newtbl = ref Tbl.empty in
  Tbl.iter
    (fun id num -> if p id then newtbl := Tbl.add id num !newtbl)
    gmap.num_tbl;
  {num_cnt = gmap.num_cnt; num_tbl = !newtbl}

(* Error report *)

open Format

let report_error ppf = function
  | Undefined_global s ->
      fprintf ppf "Reference to undefined global `%s'" s
  | Unavailable_primitive s ->
      fprintf ppf "The external function `%s' is not available" s
  | Wrong_vm s ->
      fprintf ppf "Cannot find or execute the runtime system %s" s
  | Uninitialized_global s ->
      fprintf ppf "The value of the global `%s' is not yet computed" s