Use a set to store ref registers in beam_receive

In some circumstances, as when inlining code, when some optimization
passes are disabled or with hand-written but semantically correct Core
Erlang or BEAM assembly, a fresh reference may be live in more than one
register:

    ...
    {allocate_zero,2,2}.
    ...
    {call_ext,0,{extfunc,erlang,make_ref,0}}. % Ref in [x0]
    ...
    {move,{x,0},{y,0}}. % Ref in [x0,y0]
    {move,{y,1},{x,0}}. % Ref in [y0]
    ...
    {move,{y,0},{x,0}}. % Ref in [x0,y0]
    {move,{x,0},{y,1}}. % Ref in [x0,y0,y1]
  {label,5}.
    {loop_rec,{f,6},{x,0}}. % Ref in [y0,y1]
    ...
    {loop_rec_end,{f,5}}.
  {label,6}.
    {wait,{f,5}}.
    ...

Pass beam_receive expects a single live register for the ref when it
encounters the loop_rec instruction and crashes with the following
reason:

$ erlc t.S
...
crash reason: {{case_clause,
                   {'EXIT',
                       {{case_clause,[{y,1},{y,0}]},
                        [{beam_receive,opt_recv,5,
                             [{file,"beam_receive.erl"},{line,154}]},
                         ...]}}},
               ...}

This commit teaches beam_receive how to use a set of registers instead
of a single one when tracking fresh references, thus avoiding the crash.

1 files changed, 9 insertions, 4 deletions

diff --git a/lib/compiler/test/receive_SUITE.erl b/lib/compiler/test/receive_SUITE.erl
index b91f2922fb..e60584d4ab 100644
--- a/lib/compiler/test/receive_SUITE.erl
+++ b/lib/compiler/test/receive_SUITE.erl
@@ -188,7 +188,7 @@ ref_opt(Config) when is_list(Config) ->
 ref_opt_1(Config) ->
     ?line DataDir = ?config(data_dir, Config),
     ?line PrivDir = ?config(priv_dir, Config),
-    ?line Sources = filelib:wildcard(filename:join([DataDir,"ref_opt","*.erl"])),
+    Sources = filelib:wildcard(filename:join([DataDir,"ref_opt","*.{erl,S}"])),
     ?line test_lib:p_run(fun(Src) ->
 				 do_ref_opt(Src, PrivDir)
 			 end, Sources),
@@ -196,10 +196,15 @@ ref_opt_1(Config) ->
 
 do_ref_opt(Source, PrivDir) ->
     try
-	{ok,Mod} = c:c(Source, [{outdir,PrivDir}]),
+	Ext = filename:extension(Source),
+	{ok,Mod} = compile:file(Source, [report_errors,report_warnings,
+					 {outdir,PrivDir}] ++
+					[from_asm || Ext =:= ".S" ]),
+	Base = filename:rootname(filename:basename(Source), Ext),
+    code:purge(list_to_atom(Base)),
+    BeamFile = filename:join(PrivDir, Base),
+    code:load_abs(BeamFile),
 	ok = Mod:Mod(),
-	Base = filename:rootname(filename:basename(Source), ".erl"),
-	BeamFile = filename:join(PrivDir, Base),
 	{beam_file,Mod,_,_,_,Code} = beam_disasm:file(BeamFile),
 	case Base of
 	    "no_"++_ ->