Small refactoring for null terminated values (#12086)

9 files changed, 39 insertions, 46 deletions

diff --git a/.depend b/.depend
index 2416343f7f..5439e23dae 100644
--- a/.depend
+++ b/.depend
@@ -6920,6 +6920,7 @@ tools/dumpobj.cmo : \
     bytecomp/symtable.cmi \
     tools/opnames.cmi \
     bytecomp/opcodes.cmi \
+    utils/misc.cmi \
     parsing/location.cmi \
     bytecomp/instruct.cmi \
     typing/ident.cmi \
@@ -6931,6 +6932,7 @@ tools/dumpobj.cmx : \
     bytecomp/symtable.cmx \
     tools/opnames.cmx \
     bytecomp/opcodes.cmx \
+    utils/misc.cmx \
     parsing/location.cmx \
     bytecomp/instruct.cmx \
     typing/ident.cmx \
diff --git a/bytecomp/bytelink.ml b/bytecomp/bytelink.ml
index 79976dda15..afc1a47efb 100644
--- a/bytecomp/bytelink.ml
+++ b/bytecomp/bytelink.ml
@@ -297,11 +297,6 @@ let output_debug_info oc =
     !debug_info;
   debug_info := []
 
-(* Output a list of strings with 0-termination *)
-
-let output_stringlist oc l =
-  List.iter (fun s -> output_string oc s; output_byte oc 0) l
-
 (* Transform a file name into an absolute file name *)
 
 let make_absolute file =
@@ -385,10 +380,10 @@ let link_bytecode ?final_name tolink exec_name standalone =
        (* DLL stuff *)
        if standalone then begin
          (* The extra search path for DLLs *)
-         output_stringlist outchan !Clflags.dllpaths;
+         output_string outchan (concat_null_terminated !Clflags.dllpaths);
          Bytesections.record outchan "DLPT";
          (* The names of the DLLs *)
-         output_stringlist outchan sharedobjs;
+         output_string outchan (concat_null_terminated sharedobjs);
          Bytesections.record outchan "DLLS"
        end;
        (* The names of all primitives *)
diff --git a/bytecomp/dll.ml b/bytecomp/dll.ml
index 1675a6ca21..21023d3799 100644
--- a/bytecomp/dll.ml
+++ b/bytecomp/dll.ml
@@ -164,9 +164,6 @@ let ld_library_path_contents () =
   | s ->
       Misc.split_path_contents s
 
-let split_dll_path path =
-  Misc.split_path_contents ~sep:'\000' path
-
 (* Initialization for separate compilation *)
 
 let init_compile nostdlib =
@@ -176,10 +173,10 @@ let init_compile nostdlib =
 
 (* Initialization for linking in core (dynlink or toplevel) *)
 
-let init_toplevel dllpath =
+let init_toplevel dllpaths =
   search_path :=
     ld_library_path_contents() @
-    split_dll_path dllpath @
+    dllpaths @
     ld_conf_contents();
   opened_dlls :=
     List.map (fun dll -> "", Execution dll)
diff --git a/bytecomp/dll.mli b/bytecomp/dll.mli
index 5d80e1d4be..f87554ff8f 100644
--- a/bytecomp/dll.mli
+++ b/bytecomp/dll.mli
@@ -66,6 +66,6 @@ val init_compile: bool -> unit
    the running program (CAML_LD_LIBRARY_PATH + directories in executable +
    contents of ld.conf file).  Take note of the DLLs that were opened
    when starting the running program. *)
-val init_toplevel: string -> unit
+val init_toplevel: string list -> unit
 
 val reset: unit -> unit
diff --git a/bytecomp/symtable.ml b/bytecomp/symtable.ml
index b977095237..f196ad6ed6 100644
--- a/bytecomp/symtable.ml
+++ b/bytecomp/symtable.ml
@@ -117,12 +117,9 @@ let all_primitives () =
   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
+  all_primitives()
+  |> Array.to_list
+  |> concat_null_terminated
 
 let output_primitive_names outchan =
   output_string outchan (data_primitive_names())
@@ -307,17 +304,14 @@ let init_toplevel () =
     (* Locations of globals *)
     global_table := (Obj.magic (sect.read_struct "SYMB") : GlobalMap.t);
     (* Primitives *)
-    let prims = sect.read_string "PRIM" in
+    let prims = Misc.split_null_terminated (sect.read_string "PRIM") in
     c_prim_table := PrimMap.empty;
-    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;
+    List.iter set_prim_table prims;
     (* DLL initialization *)
-    let dllpath = try sect.read_string "DLPT" with Not_found -> "" in
-    Dll.init_toplevel dllpath;
+    let dllpaths =
+      try Misc.split_null_terminated (sect.read_string "DLPT")
+      with Not_found -> [] in
+    Dll.init_toplevel dllpaths;
     (* Recover CRC infos for interfaces *)
     let crcintfs =
       try
diff --git a/tools/dumpobj.ml b/tools/dumpobj.ml
index f914b1ea60..004e1af494 100644
--- a/tools/dumpobj.ml
+++ b/tools/dumpobj.ml
@@ -477,18 +477,13 @@ let dump_obj ic =
   seek_in ic cu.cu_pos;
   print_code ic cu.cu_codesize
 
-(* Read the primitive table from an executable *)
-
-let read_primitive_table ic len =
-  let p = really_input_string ic len in
-  String.split_on_char '\000' p |> List.filter ((<>) "") |> Array.of_list
-
 (* Print an executable file *)
 
 let dump_exe ic =
   Bytesections.read_toc ic;
-  let prim_size = Bytesections.seek_section ic "PRIM" in
-  primitives := read_primitive_table ic prim_size;
+  (* Read the primitive table from an executable *)
+  let prims = Bytesections.read_section_string ic "PRIM" in
+  primitives := Array.of_list (Misc.split_null_terminated prims);
   ignore(Bytesections.seek_section ic "DATA");
   let init_data = (input_value ic : Obj.t array) in
   globals := Array.make (Array.length init_data) Empty;
diff --git a/tools/objinfo.ml b/tools/objinfo.ml
index 1b723d2018..f4d4188f4b 100644
--- a/tools/objinfo.ml
+++ b/tools/objinfo.ml
@@ -33,17 +33,8 @@ let shape = ref false
 module Magic_number = Misc.Magic_number
 
 let input_stringlist ic len =
-  let get_string_list sect len =
-    let rec fold s e acc =
-      if e != len then
-        if sect.[e] = '\000' then
-          fold (e+1) (e+1) (String.sub sect s (e-s) :: acc)
-        else fold s (e+1) acc
-      else acc
-    in fold 0 0 []
-  in
   let sect = really_input_string ic len in
-  get_string_list sect len
+  split_null_terminated sect
 
 let dummy_crc = String.make 32 '-'
 let null_crc = String.make 32 '0'
diff --git a/utils/misc.ml b/utils/misc.ml
index 18fe9bfb1d..557bc63d60 100644
--- a/utils/misc.ml
+++ b/utils/misc.ml
@@ -423,6 +423,17 @@ let find_first_mono =
 
 (* String operations *)
 
+let split_null_terminated s =
+  let[@tail_mod_cons] rec discard_last_sep = function
+    | [] | [""] -> []
+    | x :: xs -> x :: discard_last_sep xs
+  in
+  discard_last_sep (String.split_on_char '\000' s)
+
+let concat_null_terminated = function
+  | [] -> ""
+  | l -> String.concat "\000" (l @ [""])
+
 let chop_extensions file =
   let dirname = Filename.dirname file and basename = Filename.basename file in
   try
diff --git a/utils/misc.mli b/utils/misc.mli
index 52e2bc5db6..e8c716f8e4 100644
--- a/utils/misc.mli
+++ b/utils/misc.mli
@@ -257,6 +257,14 @@ val protect_writing_to_file
           channel. If the function raises an exception then [filename]
           will be removed. *)
 
+val concat_null_terminated : string list -> string
+(** [concat_null_terminated [x1;x2; ... xn]] is
+    [x1 ^ "\000" ^ x2 ^ "\000" ^ ... ^ xn ^ "\000"] *)
+
+val split_null_terminated : string -> string list
+(** [split_null_terminated s] is similar
+    [String.split_on_char '\000'] but ignores the trailing separator, if any *)
+
 val chop_extensions: string -> string
        (** Return the given file name without its extensions. The extensions
            is the longest suffix starting with a period and not including