ocaml/stdlib/printexc.ml

368 lines
12 KiB
OCaml

(**************************************************************************)
(* *)
(* 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. *)
(* *)
(**************************************************************************)
open Printf
type t = exn = ..
let printers = Atomic.make []
let locfmt = format_of_string "File \"%s\", line %d, characters %d-%d: %s"
let field x i =
let f = Obj.field x i in
if not (Obj.is_block f) then
sprintf "%d" (Obj.magic f : int) (* can also be a char *)
else if Obj.tag f = Obj.string_tag then
sprintf "%S" (Obj.magic f : string)
else if Obj.tag f = Obj.double_tag then
string_of_float (Obj.magic f : float)
else
"_"
let rec other_fields x i =
if i >= Obj.size x then ""
else sprintf ", %s%s" (field x i) (other_fields x (i+1))
let fields x =
match Obj.size x with
| 0 -> ""
| 1 -> ""
| 2 -> sprintf "(%s)" (field x 1)
| _ -> sprintf "(%s%s)" (field x 1) (other_fields x 2)
let use_printers x =
let rec conv = function
| hd :: tl ->
(match hd x with
| None | exception _ -> conv tl
| Some s -> Some s)
| [] -> None in
conv (Atomic.get printers)
let to_string_default = function
| Out_of_memory -> "Out of memory"
| Stack_overflow -> "Stack overflow"
| Match_failure(file, line, char) ->
sprintf locfmt file line char (char+5) "Pattern matching failed"
| Assert_failure(file, line, char) ->
sprintf locfmt file line char (char+6) "Assertion failed"
| Undefined_recursive_module(file, line, char) ->
sprintf locfmt file line char (char+6) "Undefined recursive module"
| x ->
let x = Obj.repr x in
if Obj.tag x <> 0 then
(Obj.magic (Obj.field x 0) : string)
else
let constructor =
(Obj.magic (Obj.field (Obj.field x 0) 0) : string) in
constructor ^ (fields x)
let to_string e =
match use_printers e with
| Some s -> s
| None -> to_string_default e
let print fct arg =
try
fct arg
with x ->
eprintf "Uncaught exception: %s\n" (to_string x);
flush stderr;
raise x
let catch fct arg =
try
fct arg
with x ->
flush stdout;
eprintf "Uncaught exception: %s\n" (to_string x);
exit 2
type raw_backtrace_slot
type raw_backtrace_entry = private int
type raw_backtrace = raw_backtrace_entry array
let raw_backtrace_entries bt = bt
external get_raw_backtrace:
unit -> raw_backtrace = "caml_get_exception_raw_backtrace"
external raise_with_backtrace: exn -> raw_backtrace -> 'a
= "%raise_with_backtrace"
type backtrace_slot =
| Known_location of {
is_raise : bool;
filename : string;
line_number : int;
start_char : int;
end_char : int;
is_inline : bool;
defname : string;
}
| Unknown_location of {
is_raise : bool
}
(* to avoid warning *)
let _ = [Known_location { is_raise = false; filename = "";
line_number = 0; start_char = 0; end_char = 0;
is_inline = false; defname = "" };
Unknown_location { is_raise = false }]
external convert_raw_backtrace_slot:
raw_backtrace_slot -> backtrace_slot = "caml_convert_raw_backtrace_slot"
external convert_raw_backtrace:
raw_backtrace -> backtrace_slot array = "caml_convert_raw_backtrace"
let convert_raw_backtrace bt =
try Some (convert_raw_backtrace bt)
with Failure _ -> None
let format_backtrace_slot pos slot =
let info is_raise =
if is_raise then
if pos = 0 then "Raised at" else "Re-raised at"
else
if pos = 0 then "Raised by primitive operation at" else "Called from"
in
match slot with
| Unknown_location l ->
if l.is_raise then
(* compiler-inserted re-raise, skipped *) None
else
Some (sprintf "%s unknown location" (info false))
| Known_location l ->
Some (sprintf "%s %s in file \"%s\"%s, line %d, characters %d-%d"
(info l.is_raise) l.defname l.filename
(if l.is_inline then " (inlined)" else "")
l.line_number l.start_char l.end_char)
let print_exception_backtrace outchan backtrace =
match backtrace with
| None ->
fprintf outchan
"(Program not linked with -g, cannot print stack backtrace)\n"
| Some a ->
for i = 0 to Array.length a - 1 do
match format_backtrace_slot i a.(i) with
| None -> ()
| Some str -> fprintf outchan "%s\n" str
done
let print_raw_backtrace outchan raw_backtrace =
print_exception_backtrace outchan (convert_raw_backtrace raw_backtrace)
(* confusingly named: prints the global current backtrace *)
let print_backtrace outchan =
print_raw_backtrace outchan (get_raw_backtrace ())
let backtrace_to_string backtrace =
match backtrace with
| None ->
"(Program not linked with -g, cannot print stack backtrace)\n"
| Some a ->
let b = Buffer.create 1024 in
for i = 0 to Array.length a - 1 do
match format_backtrace_slot i a.(i) with
| None -> ()
| Some str -> bprintf b "%s\n" str
done;
Buffer.contents b
let raw_backtrace_to_string raw_backtrace =
backtrace_to_string (convert_raw_backtrace raw_backtrace)
let backtrace_slot_is_raise = function
| Known_location l -> l.is_raise
| Unknown_location l -> l.is_raise
let backtrace_slot_is_inline = function
| Known_location l -> l.is_inline
| Unknown_location _ -> false
type location = {
filename : string;
line_number : int;
start_char : int;
end_char : int;
}
let backtrace_slot_location = function
| Unknown_location _ -> None
| Known_location l ->
Some {
filename = l.filename;
line_number = l.line_number;
start_char = l.start_char;
end_char = l.end_char;
}
let backtrace_slot_defname = function
| Unknown_location _
| Known_location { defname = "" } -> None
| Known_location l -> Some l.defname
let backtrace_slots raw_backtrace =
(* The documentation of this function guarantees that Some is
returned only if a part of the trace is usable. This gives us
a bit more work than just convert_raw_backtrace, but it makes the
API more user-friendly -- otherwise most users would have to
reimplement the "Program not linked with -g, sorry" logic
themselves. *)
match convert_raw_backtrace raw_backtrace with
| None -> None
| Some backtrace ->
let usable_slot = function
| Unknown_location _ -> false
| Known_location _ -> true in
let rec exists_usable = function
| (-1) -> false
| i -> usable_slot backtrace.(i) || exists_usable (i - 1) in
if exists_usable (Array.length backtrace - 1)
then Some backtrace
else None
let backtrace_slots_of_raw_entry entry =
backtrace_slots [| entry |]
module Slot = struct
type t = backtrace_slot
let format = format_backtrace_slot
let is_raise = backtrace_slot_is_raise
let is_inline = backtrace_slot_is_inline
let location = backtrace_slot_location
let name = backtrace_slot_defname
end
let raw_backtrace_length bt = Array.length bt
external get_raw_backtrace_slot :
raw_backtrace -> int -> raw_backtrace_slot = "caml_raw_backtrace_slot"
external get_raw_backtrace_next_slot :
raw_backtrace_slot -> raw_backtrace_slot option
= "caml_raw_backtrace_next_slot"
(* confusingly named:
returns the *string* corresponding to the global current backtrace *)
let get_backtrace () = raw_backtrace_to_string (get_raw_backtrace ())
external record_backtrace: bool -> unit = "caml_record_backtrace"
external backtrace_status: unit -> bool = "caml_backtrace_status"
let rec register_printer fn =
let old_printers = Atomic.get printers in
let new_printers = fn :: old_printers in
let success = Atomic.compare_and_set printers old_printers new_printers in
if not success then register_printer fn
external get_callstack: int -> raw_backtrace = "caml_get_current_callstack"
let exn_slot x =
let x = Obj.repr x in
if Obj.tag x = 0 then Obj.field x 0 else x
let exn_slot_id x =
let slot = exn_slot x in
(Obj.obj (Obj.field slot 1) : int)
let exn_slot_name x =
let slot = exn_slot x in
(Obj.obj (Obj.field slot 0) : string)
external get_debug_info_status : unit -> int = "caml_ml_debug_info_status"
(* Descriptions for errors in startup.h. See also backtrace.c *)
let errors = [| "";
(* FILE_NOT_FOUND *)
"(Cannot print locations:\n \
bytecode executable program file not found)";
(* BAD_BYTECODE *)
"(Cannot print locations:\n \
bytecode executable program file appears to be corrupt)";
(* WRONG_MAGIC *)
"(Cannot print locations:\n \
bytecode executable program file has wrong magic number)";
(* NO_FDS *)
"(Cannot print locations:\n \
bytecode executable program file cannot be opened;\n \
-- too many open files. Try running with OCAMLRUNPARAM=b=2)"
|]
let default_uncaught_exception_handler exn raw_backtrace =
eprintf "Fatal error: exception %s\n" (to_string exn);
print_raw_backtrace stderr raw_backtrace;
let status = get_debug_info_status () in
if status < 0 then
prerr_endline errors.(abs status);
flush stderr
let uncaught_exception_handler = ref default_uncaught_exception_handler
let set_uncaught_exception_handler fn = uncaught_exception_handler := fn
let empty_backtrace : raw_backtrace = [| |]
let try_get_raw_backtrace () =
try
get_raw_backtrace ()
with _ (* Out_of_memory? *) ->
empty_backtrace
let handle_uncaught_exception' exn debugger_in_use =
try
(* Get the backtrace now, in case one of the [at_exit] function
destroys it. *)
let raw_backtrace =
if debugger_in_use (* Same test as in [runtime/printexc.c] *) then
empty_backtrace
else
try_get_raw_backtrace ()
in
(try Stdlib.do_at_exit () with _ -> ());
try
!uncaught_exception_handler exn raw_backtrace
with exn' ->
let raw_backtrace' = try_get_raw_backtrace () in
eprintf "Fatal error: exception %s\n" (to_string exn);
print_raw_backtrace stderr raw_backtrace;
eprintf "Fatal error in uncaught exception handler: exception %s\n"
(to_string exn');
print_raw_backtrace stderr raw_backtrace';
flush stderr
with
| Out_of_memory ->
prerr_endline
"Fatal error: out of memory in uncaught exception handler"
(* This function is called by [caml_fatal_uncaught_exception] in
[runtime/printexc.c] which expects no exception is raised. *)
let handle_uncaught_exception exn debugger_in_use =
try
handle_uncaught_exception' exn debugger_in_use
with _ ->
(* There is not much we can do at this point *)
()
external register_named_value : string -> 'a -> unit
= "caml_register_named_value"
let () =
register_named_value "Printexc.handle_uncaught_exception"
handle_uncaught_exception