Allow signed and unsigned 16-bit integers in asm directives

backend/amd64/emit.ml

@@ -2688,7 +2688,8 @@ let end_assembly () =
           let l = label_to_asm_label ~section:Data l in
           ND.label l);
       efa_8 = (fun n -> ND.uint8 (Numbers.Uint8.of_nonnegative_int_exn n));
-      efa_16 = (fun n -> ND.int16 (Numbers.Int16.of_int_exn n));
+      efa_i16 = (fun n -> ND.int16 (Numbers.Int16.of_int_exn n));
+      efa_u16 = (fun n -> ND.uint16 (Numbers.Uint16.of_nonnegative_int_exn n));
       efa_32 = (fun n -> ND.int32 n);
       efa_word = (fun n -> ND.targetint (Targetint.of_int_exn n));
       efa_align = (fun n -> ND.align ~fill_x86_bin_emitter:Zero ~bytes:n);

backend/arm64/emit.ml

@@ -2220,7 +2220,8 @@ let end_assembly () =
           D.type_label ~ty:Object lbl;
           D.label lbl);
       efa_8 = (fun n -> D.uint8 (Numbers.Uint8.of_nonnegative_int_exn n));
-      efa_16 = (fun n -> D.uint16 (Numbers.Uint16.of_nonnegative_int_exn n));
+      efa_i16 = (fun n -> D.int16 (Numbers.Int16.of_int_exn n));
+      efa_u16 = (fun n -> D.uint16 (Numbers.Uint16.of_nonnegative_int_exn n));
       (* CR sspies: for some reason, we can get negative numbers here *)
       efa_32 = (fun n -> D.int32 n);
       efa_word = (fun n -> D.targetint (Targetint.of_int_exn n));

backend/emitaux.ml

@@ -199,7 +199,8 @@ type emit_frame_actions =
   { efa_code_label : Label.t -> unit;
     efa_data_label : Label.t -> unit;
     efa_8 : int -> unit;
-    efa_16 : int -> unit;
+    efa_i16 : int -> unit;
+    efa_u16 : int -> unit;
     efa_32 : int32 -> unit;
     efa_word : int -> unit;
     efa_align : int -> unit;
@@ -252,12 +253,13 @@ let emit_frames a =
        below. *)
     if fd.fd_long
     then (
-      a.efa_16 Flambda_backend_flags.max_long_frames_threshold;
+      a.efa_u16 Flambda_backend_flags.max_long_frames_threshold;
       a.efa_align 4);
-    let emit_16_or_32 = if fd.fd_long then emit_32 else a.efa_16 in
-    emit_16_or_32 (fd.fd_frame_size + flags);
-    emit_16_or_32 (List.length fd.fd_live_offset);
-    List.iter emit_16_or_32 fd.fd_live_offset;
+    let emit_signed_16_or_32 = if fd.fd_long then emit_32 else a.efa_i16 in
+    (* CR sspies: We should also split the case for 32-bit integers now. *)
+    emit_signed_16_or_32 (fd.fd_frame_size + flags);
+    emit_signed_16_or_32 (List.length fd.fd_live_offset);
+    List.iter emit_signed_16_or_32 fd.fd_live_offset;
     (match fd.fd_debuginfo with
     | _ when flags = 0 -> ()
     | Dbg_other dbg ->
@@ -295,8 +297,8 @@ let emit_frames a =
   in
   let emit_defname (_filename, defname, loc) (file_lbl, lbl) =
     let emit_loc (start_chr, end_chr, end_offset) =
-      a.efa_16 start_chr;
-      a.efa_16 end_chr;
+      a.efa_u16 start_chr;
+      a.efa_u16 end_chr;
       a.efa_32 (Int32.of_int end_offset)
     in
     (* These must be 32-bit aligned, both because they contain a 32-bit value,

backend/emitaux.mli

@@ -101,7 +101,8 @@ type emit_frame_actions =
   { efa_code_label : Label.t -> unit;
     efa_data_label : Label.t -> unit;
     efa_8 : int -> unit;
-    efa_16 : int -> unit;
+    efa_i16 : int -> unit;  (** signed 16-bit integers *)
+    efa_u16 : int -> unit;  (** unsigned 16-bit integers *)
     efa_32 : int32 -> unit;
     efa_word : int -> unit;
     efa_align : int -> unit;

runtime/caml/frame_descriptors.h

@@ -65,6 +65,8 @@ typedef struct {
   uint16_t frame_data; /* frame size and various flags */
   uint16_t num_live;
   uint16_t live_ofs[1 /* num_live */];
+  /* CR sspies: This is no longer correct. Due to recent changes in the compiler, the
+     offsets can now also be negative. */
   /*
     If frame_has_allocs(), alloc lengths follow:
         uint8_t num_allocs;