beam_listing: Optimize writing of .S files

The test suites generates listing files, so we can slightly speed
up running of test suites (especially when running 'cover') by
optimizing writing of .S files.

1 files changed, 7 insertions, 6 deletions

diff --git a/lib/compiler/src/beam_listing.erl b/lib/compiler/src/beam_listing.erl
index 50d1f3cdb1..726bb7f5eb 100644
--- a/lib/compiler/src/beam_listing.erl
+++ b/lib/compiler/src/beam_listing.erl
@@ -46,8 +46,8 @@ module(Stream, {Mod,Exp,Attr,Code,NumLabels}) ->
       fun ({function,Name,Arity,Entry,Asm}) ->
 	      io:format(Stream, "\n\n{function, ~w, ~w, ~w}.\n",
 			[Name, Arity, Entry]),
-	      foreach(fun(Op) -> print_op(Stream, Op) end, Asm) end,
-      Code);
+	      io:put_chars(Stream, format_asm(Asm))
+      end, Code);
 module(Stream, {Mod,Exp,Inter}) ->
     %% Other kinds of intermediate formats.
     io:fwrite(Stream, "~w.~n~p.~n", [Mod,Exp]),
@@ -56,10 +56,11 @@ module(Stream, [_|_]=Fs) ->
     %% Form-based abstract format.
     foreach(fun (F) -> io:format(Stream, "~p.\n", [F]) end, Fs).
 
-print_op(Stream, Label) when element(1, Label) == label ->
-    io:format(Stream, "  ~p.\n", [Label]);
-print_op(Stream, Op) ->
-    io:format(Stream, "    ~p.\n", [Op]).
+format_asm([{label,L}|Is]) ->
+    ["  {label,",integer_to_list(L),"}.\n"|format_asm(Is)];
+format_asm([I|Is]) ->
+    [io_lib:format("    ~p", [I]),".\n"|format_asm(Is)];
+format_asm([]) -> [].
 
 function(File, {function,Name,Arity,Args,Body,Vdb,_Anno}) ->
     io:nl(File),