Exporting a purely functional interface to bytecode patching.

3 files changed, 15 insertions, 15 deletions

diff --git a/kernel/cemitcodes.ml b/kernel/cemitcodes.ml
index 9b275cb6c..37794b5ea 100644
--- a/kernel/cemitcodes.ml
+++ b/kernel/cemitcodes.ml
@@ -29,11 +29,19 @@ let patch_char4 buff pos c1 c2 c3 c4 =
   String.unsafe_set buff (pos + 2) c3;
   String.unsafe_set buff (pos + 3) c4 
   
-let patch_int buff pos n =
+let patch buff (pos, n) =
   patch_char4 buff pos 
     (Char.unsafe_chr n) (Char.unsafe_chr (n asr 8))  (Char.unsafe_chr (n asr 16))
     (Char.unsafe_chr (n asr 24))
 
+let patch_int buff patches =
+  (* copy code *before* patching because of nested evaluations:
+     the code we are patching might be called (and thus "concurrently" patched)
+     and results in wrong results. Side-effects... *)
+  let buff = String.copy buff in
+  let () = List.iter (fun p -> patch buff p) patches in
+  buff
+
 (* Buffering of bytecode *)
 
 let out_buffer = ref(String.create 1024)
diff --git a/kernel/cemitcodes.mli b/kernel/cemitcodes.mli
index 54b92b912..398b60eca 100644
--- a/kernel/cemitcodes.mli
+++ b/kernel/cemitcodes.mli
@@ -13,11 +13,9 @@ val subst_patch : Mod_subst.substitution -> patch -> patch
 
 type emitcodes
 
-val copy : emitcodes -> emitcodes
-
 val length : emitcodes -> int
 
-val patch_int : emitcodes -> (*pos*)int -> int -> unit
+val patch_int : emitcodes -> ((*pos*)int * int) list -> emitcodes
 
 type to_patch = emitcodes * (patch list) * fv
 
diff --git a/kernel/csymtable.ml b/kernel/csymtable.ml
index b3f0ba5b5..e242449b1 100644
--- a/kernel/csymtable.ml
+++ b/kernel/csymtable.ml
@@ -199,19 +199,13 @@ and slot_for_fv env fv =
       end
 
 and eval_to_patch env (buff,pl,fv) =
-  (* copy code *before* patching because of nested evaluations:
-     the code we are patching might be called (and thus "concurrently" patched)
-     and results in wrong results. Side-effects... *)
-  let buff = Cemitcodes.copy buff in
   let patch = function
-    | Reloc_annot a, pos -> patch_int buff pos (slot_for_annot a)
-    | Reloc_const sc, pos -> patch_int buff pos (slot_for_str_cst sc)
-    | Reloc_getglobal kn, pos ->
-(*      Pp.msgnl (str"patching global: "++str(debug_string_of_con kn));*)
-	patch_int buff pos (slot_for_getglobal env kn);
-(*      Pp.msgnl (str"patch done: "++str(debug_string_of_con kn))*)
+    | Reloc_annot a, pos -> (pos, slot_for_annot a)
+    | Reloc_const sc, pos -> (pos, slot_for_str_cst sc)
+    | Reloc_getglobal kn, pos -> (pos, slot_for_getglobal env kn)
   in
-  List.iter patch pl;
+  let patches = List.map_left patch pl in
+  let buff = patch_int buff patches in
   let vm_env = Array.map (slot_for_fv env) fv in
   let tc = tcode_of_code buff (length buff) in
 (*Pp.msgnl (str"execute code");*)