#!/usr/bin/env escript
%% -*- erlang -*-
-mode(compile).
main(Args0) ->
{Args,Opts} = opts(Args0, #{format=>asm,no_compile=>false}),
case Args of
[OutDir] ->
do_compile(OutDir, Opts);
_ ->
usage(),
halt(1)
end.
usage() ->
S = "usage: otp-diffable-asm [OPTION] DIRECTORY\n\n"
"Options:\n"
" --asm Output to .S files (default)\n"
" --dis Output to .dis files\n"
" --no-compile Disassemble from BEAM files (use with --dis)\n"
"\n"
"DESCRIPTION\n"
"\n"
"Compile some applications from OTP (more than 700 modules) to either\n"
".S files or .dis files. The files are massaged to make them diff-friendly.\n"
"\n"
"EXAMPLES\n"
"\n"
"This example shows how the effectiveness of a compiler \n"
"optimization can be verified (alternatively, that pure code\n"
"refactoring has no effect on the generated code):\n"
"\n"
"$ scripts/diffable old\n"
"# Hack the compiler.\n"
"$ scripts/diffable new\n"
"$ diff -u old new\n"
"\n"
"This example shows how the effectiveness of loader hacks\n"
"can be verified:\n"
"\n"
"$ scripts/diffable --dis --no-compile old\n"
"# Hack ops.tab and/or one of the *instr.tab files.\n"
"$ scripts/diffable --dis --no-compile new\n"
"$ diff -u old new\n",
io:put_chars(S).
opts(["--asm"|Args], Opts) ->
opts(Args, Opts#{format:=asm});
opts(["--dis"|Args], Opts) ->
opts(Args, Opts#{format:=dis});
opts(["--no-compile"|Args], Opts) ->
opts(Args, Opts#{format:=dis,no_compile:=true});
opts(Args, Opts) ->
{Args,Opts}.
do_compile(OutDir, Opts0) ->
Opts1 = Opts0#{outdir=>OutDir},
_ = filelib:ensure_dir(filename:join(OutDir, "dummy")),
Apps = ["preloaded",
"asn1",
"stdlib",
"kernel",
"hipe",
"reltool",
"runtime_tools",
"xmerl",
"common_test",
"compiler",
"diameter",
"mnesia",
"inets",
"syntax_tools",
"parsetools",
"dialyzer",
"ssl",
"wx"],
{Files,Opts} = get_files(Apps, Opts1),
CF = choose_format(Opts),
p_run(fun(File) ->
compile_file(CF, File)
end, Files).
choose_format(#{format:=Format}=Opts) ->
case Format of
asm ->
compile_to_asm_fun(Opts);
dis ->
compile_to_dis_fun(Opts)
end.
compile_file(CF, File) ->
try
CF(File)
catch
Class:Error:Stk ->
io:format("~s: ~p ~p\n~p\n",
[File,Class,Error,Stk]),
error
end.
%%%
%%% Get names of files (either .erl files or BEAM files).
%%%
get_files(Apps, #{format:=dis,no_compile:=true}=Opts) ->
Files = get_beams(Apps),
{Files,Opts};
get_files(Apps, #{}=Opts) ->
Inc = make_includes(),
CompilerOpts = [{d,epmd_dist_high,42},
{d,epmd_dist_low,37},
{d,'VSN',1},
{d,'COMPILER_VSN',1},
{d,erlang_daemon_port,1337}|Inc],
Files0 = get_src(Apps),
Files = add_opts(Files0, CompilerOpts),
{Files,Opts}.
add_opts([F|Fs], Opts0) ->
Opts = case filename:basename(F) of
"group_history.erl" ->
Opts0 -- [{d,'VSN',1}];
_ ->
Opts0
end,
[{F,Opts}|add_opts(Fs, Opts0)];
add_opts([], _Opts) ->
[].
get_src(["preloaded"|Apps]) ->
WC = filename:join(code:root_dir(), "erts/preloaded/src/*.erl"),
filelib:wildcard(WC) ++ get_src(Apps);
get_src(["hipe"|Apps]) ->
LibDir = code:lib_dir(hipe),
WC = filename:join(LibDir, "*/*.erl"),
filelib:wildcard(WC) ++ get_src(Apps);
get_src(["inets"|Apps]) ->
LibDir = code:lib_dir(inets),
WC = filename:join(LibDir, "src/*/*.erl"),
filelib:wildcard(WC) ++ get_src(Apps);
get_src(["syntax_tools"|Apps]) ->
LibDir = code:lib_dir(syntax_tools),
WC = filename:join(LibDir, "src/*.erl"),
Files0 = filelib:wildcard(WC),
Files = [F || F <- Files0,
filename:basename(F) =/= "merl_tests.erl"],
Files ++ get_src(Apps);
get_src(["wx"|Apps]) ->
LibDir = code:lib_dir(wx),
WC1 = filename:join(LibDir, "src/gen/*.erl"),
WC2 = filename:join(LibDir, "src/*.erl"),
filelib:wildcard(WC1) ++ filelib:wildcard(WC2) ++ get_src(Apps);
get_src([App|Apps]) ->
WC = filename:join(code:lib_dir(App), "src/*.erl"),
filelib:wildcard(WC) ++ get_src(Apps);
get_src([]) -> [].
make_includes() ->
Is = [{common_test,"include"},
{inets,"include"},
{inets,"src/http_client"},
{inets,"src/http_lib"},
{inets,"src/http_server"},
{inets,"src/inets_app"},
{kernel,"include"},
{kernel,"src"},
{public_key,"include"},
{runtime_tools,"include"},
{ssh,"include"},
{snmp,"include"},
{stdlib,"include"},
{syntax_tools,"include"},
{wx,"src"},
{wx,"include"},
{xmerl,"include"}],
[{i,filename:join(code:lib_dir(App), Path)} || {App,Path} <- Is].
get_beams(["preloaded"|Apps]) ->
WC = filename:join(code:root_dir(), "erts/preloaded/ebin/*.beam"),
filelib:wildcard(WC) ++ get_beams(Apps);
get_beams([App|Apps]) ->
WC = filename:join(code:lib_dir(App), "ebin/*.beam"),
filelib:wildcard(WC) ++ get_beams(Apps);
get_beams([]) -> [].
%%%
%%% Generate renumbered .S files.
%%%
compile_to_asm_fun(#{outdir:=OutDir}) ->
fun(File) ->
compile_to_asm(File, OutDir)
end.
compile_to_asm({File,Opts}, OutDir) ->
case compile:file(File, [to_asm,binary,report_errors|Opts]) of
error ->
error;
{ok,Mod,Asm0} ->
{ok,Asm1} = beam_a:module(Asm0, []),
Asm2 = renumber_asm(Asm1),
{ok,Asm} = beam_z:module(Asm2, []),
print_asm(Mod, OutDir, Asm)
end.
print_asm(Mod, OutDir, Asm) ->
S = atom_to_list(Mod) ++ ".S",
Name = filename:join(OutDir, S),
{ok,Fd} = file:open(Name, [write,raw,delayed_write]),
ok = beam_listing(Fd, Asm),
ok = file:close(Fd).
renumber_asm({Mod,Exp,Attr,Fs0,NumLabels}) ->
EntryLabels = maps:from_list(entry_labels(Fs0)),
Fs = [fix_func(F, EntryLabels) || F <- Fs0],
{Mod,Exp,Attr,Fs,NumLabels}.
entry_labels(Fs) ->
[{Entry,{Name,Arity}} || {function,Name,Arity,Entry,_} <- Fs].
fix_func({function,Name,Arity,Entry0,Is0}, LabelMap0) ->
Entry = maps:get(Entry0, LabelMap0),
LabelMap = label_map(Is0, 1, LabelMap0),
Is = replace(Is0, [], LabelMap),
{function,Name,Arity,Entry,Is}.
label_map([{label,Old}|Is], New, Map) ->
case maps:is_key(Old, Map) of
false ->
label_map(Is, New+1, Map#{Old=>New});
true ->
label_map(Is, New, Map)
end;
label_map([_|Is], New, Map) ->
label_map(Is, New, Map);
label_map([], _New, Map) ->
Map.
replace([{label,Lbl}|Is], Acc, D) ->
replace(Is, [{label,label(Lbl, D)}|Acc], D);
replace([{test,Test,{f,Lbl},Ops}|Is], Acc, D) ->
replace(Is, [{test,Test,{f,label(Lbl, D)},Ops}|Acc], D);
replace([{test,Test,{f,Lbl},Live,Ops,Dst}|Is], Acc, D) ->
replace(Is, [{test,Test,{f,label(Lbl, D)},Live,Ops,Dst}|Acc], D);
replace([{select,I,R,{f,Fail0},Vls0}|Is], Acc, D) ->
Vls = lists:map(fun ({f,L}) -> {f,label(L, D)};
(Other) -> Other
end, Vls0),
Fail = label(Fail0, D),
replace(Is, [{select,I,R,{f,Fail},Vls}|Acc], D);
replace([{'try',R,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{'try',R,{f,label(Lbl, D)}}|Acc], D);
replace([{'catch',R,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{'catch',R,{f,label(Lbl, D)}}|Acc], D);
replace([{jump,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{jump,{f,label(Lbl, D)}}|Acc], D);
replace([{loop_rec,{f,Lbl},R}|Is], Acc, D) ->
replace(Is, [{loop_rec,{f,label(Lbl, D)},R}|Acc], D);
replace([{loop_rec_end,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{loop_rec_end,{f,label(Lbl, D)}}|Acc], D);
replace([{wait,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{wait,{f,label(Lbl, D)}}|Acc], D);
replace([{wait_timeout,{f,Lbl},To}|Is], Acc, D) ->
replace(Is, [{wait_timeout,{f,label(Lbl, D)},To}|Acc], D);
replace([{bif,Name,{f,Lbl},As,R}|Is], Acc, D) when Lbl =/= 0 ->
replace(Is, [{bif,Name,{f,label(Lbl, D)},As,R}|Acc], D);
replace([{gc_bif,Name,{f,Lbl},Live,As,R}|Is], Acc, D) when Lbl =/= 0 ->
replace(Is, [{gc_bif,Name,{f,label(Lbl, D)},Live,As,R}|Acc], D);
replace([{call,Ar,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{call,Ar,{f,label(Lbl,D)}}|Acc], D);
replace([{make_fun2,{f,Lbl},U1,U2,U3}|Is], Acc, D) ->
replace(Is, [{make_fun2,{f,label(Lbl, D)},U1,U2,U3}|Acc], D);
replace([{bs_init,{f,Lbl},Info,Live,Ss,Dst}|Is], Acc, D) when Lbl =/= 0 ->
replace(Is, [{bs_init,{f,label(Lbl, D)},Info,Live,Ss,Dst}|Acc], D);
replace([{bs_put,{f,Lbl},Info,Ss}|Is], Acc, D) when Lbl =/= 0 ->
replace(Is, [{bs_put,{f,label(Lbl, D)},Info,Ss}|Acc], D);
replace([{put_map=I,{f,Lbl},Op,Src,Dst,Live,List}|Is], Acc, D)
when Lbl =/= 0 ->
replace(Is, [{I,{f,label(Lbl, D)},Op,Src,Dst,Live,List}|Acc], D);
replace([{get_map_elements=I,{f,Lbl},Src,List}|Is], Acc, D) when Lbl =/= 0 ->
replace(Is, [{I,{f,label(Lbl, D)},Src,List}|Acc], D);
replace([{recv_mark=I,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{I,{f,label(Lbl, D)}}|Acc], D);
replace([{recv_set=I,{f,Lbl}}|Is], Acc, D) ->
replace(Is, [{I,{f,label(Lbl, D)}}|Acc], D);
replace([I|Is], Acc, D) ->
replace(Is, [I|Acc], D);
replace([], Acc, _) ->
lists:reverse(Acc).
label(Old, D) when is_integer(Old) ->
maps:get(Old, D).
%%%
%%% Compile and disassemble the loaded code.
%%%
compile_to_dis_fun(#{outdir:=OutDir,no_compile:=false}) ->
fun(File) ->
compile_to_dis(File, OutDir)
end;
compile_to_dis_fun(#{outdir:=OutDir,no_compile:=true}) ->
fun(File) ->
dis_only(File, OutDir)
end.
compile_to_dis({File,Opts}, OutDir) ->
case compile:file(File, [to_asm,binary,report_errors|Opts]) of
error ->
error;
{ok,Mod,Asm0} ->
NewMod = list_to_atom("--"++atom_to_list(Mod)++"--"),
Asm = rename_mod_in_asm(Asm0, Mod, NewMod),
AsmOpts = [from_asm,report,no_postopt,binary],
{ok,NewMod,Beam} = compile:forms(Asm, AsmOpts),
Dis0 = disasm(NewMod, Beam),
Dis1 = renumber_disasm(Dis0, Mod, NewMod),
Dis = format_disasm(Dis1),
OutFile = filename:join(OutDir, atom_to_list(Mod)++".dis"),
ok = file:write_file(OutFile, Dis)
end.
dis_only(File, OutDir) ->
Mod0 = filename:rootname(filename:basename(File)),
Mod = list_to_atom(Mod0),
Dis0 = disasm(Mod),
Dis1 = renumber_disasm(Dis0, Mod, Mod),
Dis = format_disasm(Dis1),
OutFile = filename:join(OutDir, atom_to_list(Mod)++".dis"),
ok = file:write_file(OutFile, Dis).
%%% Loading system modules can cause any number of problems.
%%% Therefore, we rename all modules to a dummy name before
%%% loading and disassembling them.
rename_mod_in_asm({OldMod,Exp,_Attr,Fs0,NumLabels}, OldMod, NewMod) ->
Fs = [fix_func_info(F, {atom,OldMod}, {atom,NewMod}) || F <- Fs0],
{NewMod,Exp,[],Fs,NumLabels}.
fix_func_info({function,Name,Arity,Entry,Is0}, OldMod, NewMod) ->
Is1 = [begin
case I of
{func_info,_,F,A} ->
{func_info,NewMod,F,A};
_ ->
I
end
end || I <- Is0],
Is = case {Name,Arity} of
{module_info,0} -> fix_module_info(Is1, OldMod, NewMod);
{module_info,1} -> fix_module_info(Is1, OldMod, NewMod);
{_,_} -> Is1
end,
{function,Name,Arity,Entry,Is}.
fix_module_info([{move,OldMod,Dst}|Is], OldMod, NewMod) ->
[{move,NewMod,Dst}|fix_module_info(Is, OldMod, NewMod)];
fix_module_info([I|Is], OldMod, NewMod) ->
[I|fix_module_info(Is, OldMod, NewMod)];
fix_module_info([], _, _) ->
[].
%%% Disassemble the module.
disasm(Mod, Beam) ->
{module,Mod} = code:load_binary(Mod, "", Beam),
disasm(Mod).
disasm(Mod) ->
disasm_1(Mod:module_info(functions), Mod).
disasm_1([{Name,Arity}|Fs], Mod) ->
MFA = {Mod,Name,Arity},
Dis = disasm_func({MFA,<<>>,MFA}, MFA),
[{Name,Arity,Dis}|disasm_1(Fs, Mod)];
disasm_1([], _) ->
[].
disasm_func({Next,_,MFA}, MFA) ->
case erts_debug:disassemble(Next) of
{_,Line,MFA}=Cont ->
[Line|disasm_func(Cont, MFA)];
{_,_,_} ->
[];
false ->
[]
end.
%%% Renumber the disassembled module to use labels instead of
%%% absolute addresses. Also do other translations so that the
%%% output will be the same each time (for the same BEAM file
%%% runtime system).
renumber_disasm(Fs0, OldMod, NewMod) ->
Fs1 = split_dis_lines(Fs0),
renumber_disasm_fs(Fs1, OldMod, NewMod).
renumber_disasm_fs([{Name,Arity,Is0}|Fs], OldMod, NewMod) ->
Labels = find_labels(Is0, Name, Arity),
Is1 = rename_mod(Is0, OldMod, NewMod),
Is = renumber_disasm_func(Is1, Labels),
[{Name,Arity,Is}|renumber_disasm_fs(Fs, OldMod, NewMod)];
renumber_disasm_fs([], _OldMod, _NewMod) ->
[].
renumber_disasm_func([[A,OpCode|Ops0]|Is], Labels) ->
Spaces = " ",
Left = case maps:find(A, Labels) of
{ok,Lbl} ->
case byte_size(Lbl) of
LblSize when LblSize < length(Spaces) ->
[$\n,Lbl,":",lists:nth(LblSize, Spaces)];
_ ->
[Lbl,":\n"|Spaces]
end;
error ->
Spaces
end,
Ops1 = [replace_label(Op, Labels) || Op <- Ops0],
Ops = handle_special_instrs(OpCode, Ops1),
[[Left,OpCode|Ops]|renumber_disasm_func(Is, Labels)];
renumber_disasm_func([], _) ->
[].
handle_special_instrs(<<"i_get_hash_cId">>, [Key,_Hash,Dst]) ->
[Key,hash_value(),Dst];
handle_special_instrs(<<"i_get_map_element_",_/binary>>,
[Fail,Src,Key,_Hash,Dst]) ->
[Fail,Src,Key,hash_value(),Dst];
handle_special_instrs(<<"i_get_map_elements_",_/binary>>,
[Fail,Src,N,Space|List0]) ->
List1 = rejoin_atoms(List0),
List = fix_hash_value(List1),
[Fail,Src,N,Space|List];
handle_special_instrs(<<"i_select_val_bins_",_/binary>>,
[Src,Fail,Num|List0]) ->
%% Atoms are sorted in atom-number order, which is
%% different every time the runtime system is restarted.
%% Resort the values in ASCII order.
List1 = rejoin_atoms(List0),
{Values0,Labels0} = lists:split(length(List1) div 2, List1),
Zipped0 = lists:zip(Values0, Labels0),
Zipped = lists:sort(Zipped0),
{Values,Labels} = lists:unzip(Zipped),
[Src,Fail,Num|Values++Labels];
handle_special_instrs(<<"i_select_val_lins_",_/binary>>,
[Src,Fail,Num|List0]) ->
List1 = rejoin_atoms(List0),
{Values0,Labels0} = lists:split(length(List1) div 2, List1),
Values1 = lists:droplast(Values0),
Labels1 = lists:droplast(Labels0),
Vlast = lists:last(Values0),
Llast = lists:last(Labels0),
Zipped0 = lists:zip(Values1, Labels1),
Zipped = lists:sort(Zipped0),
{Values,Labels} = lists:unzip(Zipped),
[Src,Fail,Num|Values++[Vlast]++Labels++[Llast]];
handle_special_instrs(_, Ops) ->
Ops.
fix_hash_value([Val,Dst,_Hash|T]) ->
[Val,Dst,hash_value()|fix_hash_value(T)];
fix_hash_value([]) ->
[].
hash_value() ->
<<"--hash-value--">>.
replace_label(<<"f(",T/binary>>, Labels) ->
replace_label_1("f(", T, Labels);
replace_label(<<"j(",T/binary>>, Labels) ->
replace_label_1("j(", T, Labels);
replace_label(Op, _Labels) ->
Op.
replace_label_1(Prefix, Lbl0, Labels) ->
Sz = byte_size(Lbl0)-1,
Lbl = case Lbl0 of
<<"0)">> ->
Lbl0;
<<Lbl1:Sz/bytes,")">> ->
[maps:get(Lbl1, Labels),")"];
_ ->
Lbl0
end,
iolist_to_binary([Prefix,Lbl]).
split_dis_lines(Fs) ->
{ok,RE} = re:compile(<<"\\s*\\n$">>),
Colon = binary:compile_pattern(<<": ">>),
Space = binary:compile_pattern(<<" ">>),
[split_dis_func(F, RE, Colon, Space) || F <- Fs].
split_dis_func({Name,Arity,Lines0}, RE, Colon, Space) ->
Lines1 = [re:replace(L, RE, <<>>, [{return,binary}]) || L <- Lines0],
Lines2 = [begin
[A,I] = binary:split(L, Colon),
Ops = binary:split(I, Space, [global]),
[A|Ops]
end|| L <- Lines1],
{Name,Arity,Lines2}.
rejoin_atoms([<<"'",Tail/binary>> = Bin0,Next|Ops]) ->
Sz = byte_size(Tail) - 1,
case Tail of
<<_:Sz/bytes,"'">> ->
[Bin0|rejoin_atoms([Next|Ops])];
<<>> ->
Bin = <<Bin0/binary,$\s,Next/binary>>,
rejoin_atoms([Bin|Ops]);
_ ->
Bin = <<Bin0/binary,$\s,Next/binary>>,
rejoin_atoms([Bin|Ops])
end;
rejoin_atoms(Ops) ->
Ops.
find_labels(Is, Name, Arity) ->
[_,[Entry|_]|_] = Is,
EntryLabel = iolist_to_binary(io_lib:format("~p/~p", [Name,Arity])),
{ok,RE} = re:compile(<<"^[fj]\\(([0-9A-F]{8,16})\\)$">>),
Ls0 = [find_labels_1(Ops, RE) || [_Addr,_OpCode|Ops] <- Is],
Ls1 = lists:flatten(Ls0),
Ls2 = lists:usort(Ls1),
Ls3 = number(Ls2, 1),
Ls = [{Entry,EntryLabel}|Ls3],
maps:from_list(Ls).
find_labels_1([Op|Ops], RE) ->
case re:run(Op, RE, [{capture,all_but_first,binary}]) of
nomatch ->
find_labels_1(Ops, RE);
{match,[M]} ->
[M|find_labels_1(Ops, RE)]
end;
find_labels_1([], _) ->
[].
number([H|T], N) ->
S = iolist_to_binary(["L",integer_to_list(N)]),
[{H,S}|number(T, N+1)];
number([], _) ->
[].
format_disasm([{_,_,Is}|Fs]) ->
L = [lists:join(" ", I) || I <- Is],
[lists:join("\n", L),"\n\n"|format_disasm(Fs)];
format_disasm([]) ->
[].
rename_mod(Is, OldMod0, NewMod) ->
OldMod = atom_to_binary(OldMod0, utf8),
Pattern = <<"'",(atom_to_binary(NewMod, utf8))/binary,"'">>,
[rename_mod_1(I, Pattern, OldMod) || I <- Is].
rename_mod_1([A,OpCode|Ops], Pat, Replacement) ->
[A,OpCode|[rename_mod_2(Op, Pat, Replacement) || Op <- Ops]].
rename_mod_2(Subject, Pat, Replacement) ->
Sz = byte_size(Pat),
case Subject of
<<Pat:Sz/bytes,Tail/binary>> ->
<<Replacement/binary,Tail/binary>>;
_ ->
Subject
end.
%%%
%%% Run tasks in parallel.
%%%
p_run(Test, List) ->
N = erlang:system_info(schedulers) * 2,
p_run_loop(Test, List, N, [], 0).
p_run_loop(_, [], _, [], Errors) ->
io:put_chars("\r \n"),
case Errors of
0 ->
ok;
N ->
io:format("~p errors\n", [N]),
halt(1)
end;
p_run_loop(Test, [H|T], N, Refs, Errors) when length(Refs) < N ->
{_,Ref} = erlang:spawn_monitor(fun() -> exit(Test(H)) end),
p_run_loop(Test, T, N, [Ref|Refs], Errors);
p_run_loop(Test, List, N, Refs0, Errors0) ->
io:format("\r~p ", [length(List)+length(Refs0)]),
receive
{'DOWN',Ref,process,_,Res} ->
Errors = case Res of
ok -> Errors0;
error -> Errors0 + 1
end,
Refs = Refs0 -- [Ref],
p_run_loop(Test, List, N, Refs, Errors)
end.
%%%
%%% Borrowed from beam_listing and tweaked.
%%%
beam_listing(Stream, {Mod,Exp,Attr,Code,NumLabels}) ->
Head = ["%% -*- encoding:latin-1 -*-\n",
io_lib:format("{module, ~p}. %% version = ~w\n",
[Mod, beam_opcodes:format_number()]),
io_lib:format("\n{exports, ~p}.\n", [Exp]),
io_lib:format("\n{attributes, ~p}.\n", [Attr]),
io_lib:format("\n{labels, ~p}.\n", [NumLabels])],
ok = file:write(Stream, Head),
lists:foreach(
fun ({function,Name,Arity,Entry,Asm}) ->
S = [io_lib:format("\n\n{function, ~w, ~w, ~w}.\n",
[Name,Arity,Entry])|format_asm(Asm)],
ok = file:write(Stream, S)
end, Code).
format_asm([{label,_}=I|Is]) ->
[io_lib:format(" ~p", [I]),".\n"|format_asm(Is)];
format_asm([I|Is]) ->
[io_lib:format(" ~p", [I]),".\n"|format_asm(Is)];
format_asm([]) -> [].
