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|
(***********************************************************************)
(* *)
(* 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 Q Public License version 1.0. *)
(* *)
(***********************************************************************)
(* The "trace" facility *)
open Format
open Misc
open Longident
open Types
open Toploop
type codeptr = Obj.t
type traced_function =
{ path: Path.t; (* Name under which it is traced *)
closure: Obj.t; (* Its function closure (patched) *)
actual_code: codeptr; (* Its original code pointer *)
instrumented_fun: codeptr -> Obj.t -> Obj.t -> Obj.t }
(* Printing function *)
let traced_functions = ref ([] : traced_function list)
(* Check if a function is already traced *)
let is_traced clos =
let rec is_traced = function
[] -> None
| tf :: rem -> if tf.closure == clos then Some tf.path else is_traced rem
in is_traced !traced_functions
(* Get or overwrite the code pointer of a closure *)
let get_code_pointer cls = Obj.field cls 0
let set_code_pointer cls ptr = Obj.set_field cls 0 ptr
(* Call a traced function (use old code pointer, but new closure as
environment so that recursive calls are also traced).
It is necessary to wrap Meta.invoke_traced_function in an ML function
so that the RETURN at the end of the ML wrapper takes us to the
code of the function. *)
let invoke_traced_function codeptr env arg =
Meta.invoke_traced_function codeptr env arg
let print_label ppf l = if l <> "" then fprintf ppf "%s:" l
(* If a function returns a functional value, wrap it into a trace code *)
let rec instrument_result env name ppf clos_typ =
match (Ctype.repr(Ctype.expand_head env clos_typ)).desc with
| Tarrow(l, t1, t2, _) ->
let starred_name =
match name with
| Lident s -> Lident(s ^ "*")
| Ldot(lid, s) -> Ldot(lid, s ^ "*")
| Lapply(l1, l2) -> fatal_error "Trace.instrument_result" in
let trace_res = instrument_result env starred_name ppf t2 in
(fun clos_val ->
Obj.repr (fun arg ->
if not !may_trace then
(Obj.magic clos_val : Obj.t -> Obj.t) arg
else begin
may_trace := false;
try
fprintf ppf "@[<2>%a <--@ %a%a@]@."
Printtyp.longident starred_name
print_label l
(print_value !toplevel_env arg) t1;
may_trace := true;
let res = (Obj.magic clos_val : Obj.t -> Obj.t) arg in
may_trace := false;
fprintf ppf "@[<2>%a -->@ %a@]@."
Printtyp.longident starred_name
(print_value !toplevel_env res) t2;
may_trace := true;
trace_res res
with exn ->
may_trace := false;
fprintf ppf "@[<2>%a raises@ %a@]@."
Printtyp.longident starred_name
(print_value !toplevel_env (Obj.repr exn)) Predef.type_exn;
may_trace := true;
raise exn
end))
| _ -> (fun v -> v)
(* Same as instrument_result, but for a toplevel closure (modified in place) *)
let instrument_closure env name ppf clos_typ =
match (Ctype.repr(Ctype.expand_head env clos_typ)).desc with
| Tarrow(l, t1, t2, _) ->
let trace_res = instrument_result env name ppf t2 in
(fun actual_code closure arg ->
if not !may_trace then begin
let res = invoke_traced_function actual_code closure arg
in res (* do not remove let, prevents tail-call to invoke_traced_ *)
end else begin
may_trace := false;
try
fprintf ppf "@[<2>%a <--@ %a%a@]@."
Printtyp.longident name
print_label l
(print_value !toplevel_env arg) t1;
may_trace := true;
let res = invoke_traced_function actual_code closure arg in
may_trace := false;
fprintf ppf "@[<2>%a -->@ %a@]@."
Printtyp.longident name
(print_value !toplevel_env res) t2;
may_trace := true;
trace_res res
with exn ->
may_trace := false;
fprintf ppf "@[<2>%a raises@ %a@]@."
Printtyp.longident name
(print_value !toplevel_env (Obj.repr exn)) Predef.type_exn;
may_trace := true;
raise exn
end)
| _ -> assert false
(* Given the address of a closure, find its tracing info *)
let rec find_traced_closure clos = function
| [] -> fatal_error "Trace.find_traced_closure"
| f :: rem -> if f.closure == clos then f else find_traced_closure clos rem
(* Trace the application of an (instrumented) closure to an argument *)
let print_trace clos arg =
let f = find_traced_closure clos !traced_functions in
f.instrumented_fun f.actual_code clos arg
|
