ocaml/bytecomp/symtable.ml

301 lines
8.8 KiB
OCaml

(***********************************************************************)
(* *)
(* 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 Emitcode
(* Functions for batch linking *)
type error =
Undefined_global of string
| Unavailable_primitive of string
| Wrong_vm 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 raise(Error(Unavailable_primitive name))
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 output_primitive_names outchan =
let prim = all_primitives() in
for i = 0 to Array.length prim - 1 do
output_string outchan prim.(i); output_char outchan '\000'
done
open Printf
let output_primitive_table outchan =
let prim = all_primitives() in
fprintf outchan "\
#ifdef __cplusplus\n\
extern \"C\" {\n\
#endif\n";
for i = 0 to Array.length prim - 1 do
fprintf outchan "extern long %s();\n" prim.(i)
done;
fprintf outchan "typedef long (*primitive)();\n";
fprintf outchan "primitive 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 * names_of_cprim[] = {\n";
for i = 0 to Array.length prim - 1 do
fprintf outchan " \"%s\",\n" prim.(i)
done;
fprintf outchan " (char *) 0 };\n";
fprintf outchan "\
#ifdef __cplusplus\n\
}\n\
#endif\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;
(* Enter 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
| 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_pointer i -> Obj.repr i
| 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
(* 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 := []
(* Initialize the linker for toplevel use *)
let init_toplevel () =
(* Read back the known global symbols from the executable file *)
let ic = open_in_bin Sys.argv.(0) in
begin try
Bytesections.read_toc ic;
ignore(Bytesections.seek_section ic "SYMB");
global_table := (input_value ic : Ident.t numtable)
with Bytesections.Bad_magic_number | Not_found | Failure _ ->
fatal_error "Toplevel bytecode executable is corrupted"
end;
close_in ic;
(* Enter the known C primitives *)
Array.iter set_prim_table
(Meta.available_primitives())
(* 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
(* 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