Merge pull request #358 from copy/master

Fix integer overflow warning on jsoo (#346)

src/core/CCInt.ml

@@ -318,7 +318,54 @@ let range_by ~step i j yield =
       (CCInt.range_by ~step:1 i j |> Iter.to_list) \
       (CCInt.range i j |> Iter.to_list) )
 *)
-(* popcount comes from [Shims] as it's 32/64 bits dependent, see #327 *)
+
+(* we use the simple version for non-64 bits. *)
+let popcount_32 (b:int) : int =
+  let rec loop count x =
+    if x=0 then count
+    else loop (count+1) (x land (x-1))
+  in
+  loop 0 b
+
+(*
+  from https://en.wikipedia.org/wiki/Hamming_weight
+
+  //This uses fewer arithmetic operations than any other known
+  //implementation on machines with slow multiplication.
+  //It uses 17 arithmetic operations.
+  int popcount_2(uint64_t x) {
+    x -= (x >> 1) & m1;             //put count of each 2 bits into those 2 bits
+    x = (x & m2) + ((x >> 2) & m2); //put count of each 4 bits into those 4 bits
+    x = (x + (x >> 4)) & m4;        //put count of each 8 bits into those 8 bits
+    x += x >>  8;  //put count of each 16 bits into their lowest 8 bits
+    x += x >> 16;  //put count of each 32 bits into their lowest 8 bits
+    x += x >> 32;  //put count of each 64 bits into their lowest 8 bits
+    return x & 0x7f;
+  }
+
+   m1 = 0x5555555555555555
+   m2 = 0x3333333333333333
+   m4 = 0x0f0f0f0f0f0f0f0f
+*)
+let popcount_64 (b:int) : int =
+  (* break up into parts to allow compilation on 32-bit and jsoo *)
+  let m1 = 0x55555555 lor 0x55555555 lsl 32 in
+  let m2 = 0x33333333 lor 0x33333333 lsl 32 in
+  let m4 = 0x0f0f0f0f lor 0x0f0f0f0f lsl 32 in
+  let b = b - ((b lsr 1) land m1) in
+  let b = (b land m2) + ((b lsr 2) land m2) in
+  let b = (b + (b lsr 4)) land m4 in
+  let b = b + (b lsr 8) in
+  let b = b + (b lsr 16) in
+  let b = b + (b lsr 32) in
+  b land 0x7f
+
+(* pick at runtime, see:
+  - https://github.com/c-cube/ocaml-containers/issues/346
+  - https://github.com/ocsigen/js_of_ocaml/issues/1079
+  *)
+let popcount =
+  if Sys.int_size = 63 then popcount_64 else popcount_32
 
 (*$=
   0 (popcount 0)

src/core/mkshims.ml

@@ -204,57 +204,6 @@ let shims_int_post_408 = "
   (** {{: https://caml.inria.fr/pub/docs/manual-ocaml/libref/Int.html} Documentation for the standard Int module}*)
 "
 
-let shims_int_non_64bit = "
-(* we use the simple version for non-64 bits. *)
-let popcount (b:int) : int =
-  let rec loop count x =
-    if x=0 then count
-    else loop (count+1) (x land (x-1))
-  in
-  loop 0 b
-
-"
-
-(* 64 bits: include basic version *)
-let shims_int_64bit =
-shims_int_non_64bit ^ "
-(*
-  from https://en.wikipedia.org/wiki/Hamming_weight
-
-  //This uses fewer arithmetic operations than any other known
-  //implementation on machines with slow multiplication.
-  //It uses 17 arithmetic operations.
-  int popcount_2(uint64_t x) {
-    x -= (x >> 1) & m1;             //put count of each 2 bits into those 2 bits
-    x = (x & m2) + ((x >> 2) & m2); //put count of each 4 bits into those 4 bits
-    x = (x + (x >> 4)) & m4;        //put count of each 8 bits into those 8 bits
-    x += x >>  8;  //put count of each 16 bits into their lowest 8 bits
-    x += x >> 16;  //put count of each 32 bits into their lowest 8 bits
-    x += x >> 32;  //put count of each 64 bits into their lowest 8 bits
-    return x & 0x7f;
-  }
-
-   m1 = 0x5555555555555555
-   m2 = 0x3333333333333333
-   m4 = 0x0f0f0f0f0f0f0f0f
-*)
-let popcount_64_ (b:int) : int =
-  let b = b - ((b lsr 1) land 0x5555555555555555) in
-  let b = (b land 0x3333333333333333) + ((b lsr 2) land 0x3333333333333333) in
-  let b = (b + (b lsr 4)) land 0x0f0f0f0f0f0f0f0f in
-  let b = b + (b lsr 8) in
-  let b = b + (b lsr 16) in
-  let b = b + (b lsr 32) in
-  b land 0x7f
-
-(* pick at runtime, see:
-  - https://github.com/c-cube/ocaml-containers/issues/346
-  - https://github.com/ocsigen/js_of_ocaml/issues/1079
-  *)
-let popcount =
-  if Sys.int_size = 63 then popcount_64_ else popcount
-"
-
 let shims_either_pre_412 = "
   type ('a, 'b) t = Left of 'a | Right of 'b
   "
@@ -282,18 +231,8 @@ let () =
     write_file "CCShimsFun_.mli" (if (major, minor) >= (4,8) then shims_fun_mli_post_408 else shims_fun_mli_pre_408);
     write_file "CCShimsMkLet_.ml" (if (major, minor) >= (4,8) then shims_let_op_post_408 else shims_let_op_pre_408);
     write_file "CCShimsMkLetList_.ml" (if (major, minor) >= (4,8) then shims_let_op_list_post_408 else shims_let_op_list_pre_408);
-    (* see if we target native 64 bits (rather than 32 bits or jsoo or sth else) *)
-    let int_size =
-      try C.ocaml_config_var_exn c "int_size" |> int_of_string
-      with e ->
-        let n = Sys.int_size in (* default to current version *)
-        Printf.eprintf "cannot obtain target int_size:\n%s\ndefaulting to %d\n%!"
-          (Printexc.to_string e) n;
-        n
-    in
     write_file "CCShimsInt_.ml"
-      ((if (major, minor) >= (4,8) then shims_int_post_408 else shims_int_pre_408)
-      ^ if int_size=63 then shims_int_64bit else shims_int_non_64bit);
+      (if (major, minor) >= (4,8) then shims_int_post_408 else shims_int_pre_408);
     write_file "CCShimsEither_.ml"
       (if (major, minor) >= (4,12) then shims_either_post_412
        else shims_either_pre_412);