Address comments about comments, names, and type of bound_error_call

asmcomp/amd64/emit.mlp

@@ -66,6 +66,7 @@ let emit_debug_info dbg =
 
 let fp = Config.with_frame_pointers
 
+(* Record calls to the GC -- we've moved them out of the way *)
 type gc_call =
   { gc_size: int;                       (* Allocation size, in bytes *)
     gc_lbl: label;                      (* Entry label *)
@@ -75,22 +76,24 @@ type gc_call =
     (* Spacetime node hole pointer and index *)
   }
 
+(* Record calls to caml_ml_array_bound_error.
+   In -g mode, or when using Spacetime profiling, we maintain one call to
+   caml_ml_array_bound_error per bound check site.  Without -g, we can share
+   a single call. *)
 type bound_error_call =
   { bd_lbl: label;                      (* Entry label *)
     bd_frame: label;                    (* Label of frame descriptor *)
     bd_spacetime : (X86_ast.arg * int) option;
     (* As for [gc_call]. *)
   }
 
-(* Environment *)
-type env = {
+(* Environment for emitting a function *)
+type per_function_env = {
   f : fundecl;
   stack_offset : int;
   call_gc_sites : gc_call list;
   bound_error_sites : bound_error_call list;
-  bound_error_call : int;
-  symbols_defined : String.Set.t;
-  symbols_used : String.Set.t;
+  bound_error_call : label option;
 }
 
 let mk_env f =
@@ -99,13 +102,9 @@ let mk_env f =
     stack_offset = 0;
     call_gc_sites = [];
     bound_error_sites = [];
-    bound_error_call = 0;
-    symbols_defined = String.Set.empty;
-    symbols_used = String.Set.empty;
+    bound_error_call = None;
   }
 
-(* Tradeoff between code size and code speed *)
-
 let frame_size env =                     (* includes return address *)
   if env.f.fun_frame_required then begin
     let sz =
@@ -297,8 +296,6 @@ let spacetime_before_uninstrumented_call ~node_ptr ~index env =
   assert (index >= 2);
   I.add (int (index * 8)) (reg Proc.loc_spacetime_node_hole ~env)
 
-(* Record calls to the GC -- we've moved them out of the way *)
-
 let emit_call_gc gc ~env =
   def_label gc.gc_lbl;
   begin match gc.gc_spacetime with
@@ -317,12 +314,6 @@ let emit_call_gc gc ~env =
   def_label gc.gc_frame;
   I.jmp (label gc.gc_return_lbl)
 
-
-(* Record calls to caml_ml_array_bound_error.
-   In -g mode, or when using Spacetime profiling, we maintain one call to
-   caml_ml_array_bound_error per bound check site.  Without -g, we can share
-   a single call. *)
-
 let bound_error_label ?label dbg ~spacetime env =
   if !Clflags.debug || Config.spacetime then begin
     let lbl_bound_error = new_label() in
@@ -333,12 +324,12 @@ let bound_error_label ?label dbg ~spacetime env =
         bd_spacetime = spacetime; } :: env.bound_error_sites; } in
     (lbl_bound_error, env)
   end else begin
-    let env =
-      if env.bound_error_call = 0 then
-        { env with bound_error_call = new_label() }
-      else env
-    in
-    (env.bound_error_call, env)
+    match env.bound_error_call with
+    | None ->
+      let lbl = new_label () in
+      let env = { env with bound_error_call = Some lbl } in
+      lbl, env
+    | Some lbl -> lbl, env
   end
 
 let emit_call_bound_error env bd =
@@ -353,10 +344,11 @@ let emit_call_bound_error env bd =
 
 let emit_call_bound_errors env =
   List.iter (emit_call_bound_error env) env.bound_error_sites;
-  if env.bound_error_call > 0 then begin
-    def_label env.bound_error_call;
+  match env.bound_error_call with
+  | Some lbl ->
+    def_label lbl;
     emit_call "caml_ml_array_bound_error"
-  end
+  | None -> ()
 
 (* Names for instructions *)