Teach erl_expand_records to translate module-less calls

As the next step in eliminating sys_pre_expand, teach
erl_expand_records to handle calls without explicit module name. If
such call refer to a BIF or imported function, add an explicit module
name.

That means that any subsequent pass will know that a call without
a module name is always to a local function defined in the module.

2 files changed, 62 insertions, 28 deletions

diff --git a/lib/stdlib/doc/src/erl_expand_records.xml b/lib/stdlib/doc/src/erl_expand_records.xml
index 7e4aa2db37..b6aa75ed03 100644
--- a/lib/stdlib/doc/src/erl_expand_records.xml
+++ b/lib/stdlib/doc/src/erl_expand_records.xml
@@ -45,8 +45,10 @@
       <name name="module" arity="2"/>
       <fsummary>Expand all records in a module.</fsummary>
       <desc>
-        <p>Expands all records in a module. The returned module has no
-          references to records, attributes, or code.</p>
+        <p>Expands all records in a module to use explicit tuple
+        operations and adds explicit module names to calls to BIFs and
+        imported functions.  The returned module has no references to
+        records, attributes, or code.</p>
       </desc>
     </func>
   </funcs>
diff --git a/lib/stdlib/src/erl_expand_records.erl b/lib/stdlib/src/erl_expand_records.erl
index ebcbc54ab1..ab47f05320 100644
--- a/lib/stdlib/src/erl_expand_records.erl
+++ b/lib/stdlib/src/erl_expand_records.erl
@@ -17,7 +17,8 @@
 %%
 %% %CopyrightEnd%
 %%
-%% Purpose : Expand records into tuples.
+%% Purpose: Expand records into tuples. Also add explicit module
+%% names to calls to imported functions and BIFs.
 
 %% N.B. Although structs (tagged tuples) are not yet allowed in the
 %% language there is code included in pattern/2 and expr/3 (commented out)
@@ -31,7 +32,7 @@
 
 -record(exprec, {compile=[],          % Compile flags
                  vcount=0,            % Variable counter
-                 imports=[],          % Imports
+		 calltype=#{},	      % Call types
                  records=dict:new(),  % Record definitions
                  strict_ra=[],        % strict record accesses
                  checked_ra=[]        % successfully accessed records
@@ -46,22 +47,34 @@
 %% erl_lint without errors.
 module(Fs0, Opts0) ->
     Opts = compiler_options(Fs0) ++ Opts0,
-    St0 = #exprec{compile = Opts},
+    Calltype = init_calltype(Fs0),
+    St0 = #exprec{compile = Opts, calltype = Calltype},
     {Fs,_St} = forms(Fs0, St0),
     Fs.
 
 compiler_options(Forms) ->
     lists:flatten([C || {attribute,_,compile,C} <- Forms]).
 
+init_calltype(Forms) ->
+    Locals = [{{Name,Arity},local} || {function,_,Name,Arity,_} <- Forms],
+    Ctype = maps:from_list(Locals),
+    init_calltype_imports(Forms, Ctype).
+
+init_calltype_imports([{attribute,_,import,{Mod,Fs}}|T], Ctype0) ->
+    true = is_atom(Mod),
+    Ctype = foldl(fun(FA, Acc) ->
+			  Acc#{FA=>{imported,Mod}}
+		  end, Ctype0, Fs),
+    init_calltype_imports(T, Ctype);
+init_calltype_imports([_|T], Ctype) ->
+    init_calltype_imports(T, Ctype);
+init_calltype_imports([], Ctype) -> Ctype.
+
 forms([{attribute,_,record,{Name,Defs}}=Attr | Fs], St0) ->
     NDefs = normalise_fields(Defs),
     St = St0#exprec{records=dict:store(Name, NDefs, St0#exprec.records)},
     {Fs1, St1} = forms(Fs, St),
     {[Attr | Fs1], St1};
-forms([{attribute,L,import,Is} | Fs0], St0) ->
-    St1 = import(Is, St0),
-    {Fs,St2} = forms(Fs0, St1),
-    {[{attribute,L,import,Is} | Fs], St2};
 forms([{function,L,N,A,Cs0} | Fs0], St0) ->
     {Cs,St1} = clauses(Cs0, St0),
     {Fs,St2} = forms(Fs0, St1),
@@ -334,8 +347,16 @@ expr({'receive',Line,Cs0,To0,ToEs0}, St0) ->
     {ToEs,St2} = exprs(ToEs0, St1),
     {Cs,St3} = clauses(Cs0, St2),
     {{'receive',Line,Cs,To,ToEs},St3};
-expr({'fun',_,{function,_F,_A}}=Fun, St) ->
-    {Fun,St};
+expr({'fun',Lf,{function,F,A}}=Fun0, St0) ->
+    case erl_internal:bif(F, A) of
+        true ->
+	    {As,St1} = new_vars(A, Lf, St0),
+	    Cs = [{clause,Lf,As,[],[{call,Lf,{atom,Lf,F},As}]}],
+	    Fun = {'fun',Lf,{clauses,Cs}},
+	    expr(Fun,  St1);
+	false ->
+	    {Fun0,St0}
+    end;
 expr({'fun',_,{function,_M,_F,_A}}=Fun, St) ->
     {Fun,St};
 expr({'fun',Line,{clauses,Cs0}}, St0) ->
@@ -352,14 +373,30 @@ expr({call,Line,{remote,_,{atom,_,erlang},{atom,_,is_record}},
 expr({call,Line,{tuple,_,[{atom,_,erlang},{atom,_,is_record}]},
       [A,{atom,_,Name}]}, St) ->
     record_test(Line, A, Name, St);
+expr({call,Line,{atom,_La,record_info},[_,_]=As0}, St0) ->
+    {As,St1} = expr_list(As0, St0),
+    record_info_call(Line, As, St1);
 expr({call,Line,{atom,_La,N}=Atom,As0}, St0) ->
     {As,St1} = expr_list(As0, St0),
     Ar = length(As),
-    case {N,Ar} =:= {record_info,2} andalso not imported(N, Ar, St1) of
-	true ->
-	    record_info_call(Line, As, St1);
-	false ->
-	    {{call,Line,Atom,As},St1}
+    NA = {N,Ar},
+    case St0#exprec.calltype of
+	#{NA := local} ->
+	    {{call,Line,Atom,As},St1};
+	#{NA := {imported,Module}} ->
+	    ModAtom = {atom,Line,Module},
+	    {{call,Line,{remote,Line,ModAtom,Atom},As},St1};
+	_ ->
+	    case erl_internal:bif(N, Ar) of
+		true ->
+		    ModAtom = {atom,Line,erlang},
+		    {{call,Line,{remote,Line,ModAtom,Atom},As},St1};
+		false ->
+		    %% Call to a module_info/0,1 or one of the
+		    %% pseudo-functions in the shell. Leave it as
+		    %% a local call.
+		    {{call,Line,Atom,As},St1}
+	    end
     end;
 expr({call,Line,{remote,Lr,M,F},As0}, St0) ->
     {[M1,F1 | As1],St1} = expr_list([M,F | As0], St0),
@@ -769,6 +806,13 @@ bin_element({bin_element,Line,Expr,Size,Type}, {Es,St0}) ->
                   end,
     {[{bin_element,Line,Expr1,Size1,Type} | Es],St2}.
 
+new_vars(N, L, St) -> new_vars(N, L, St, []).
+
+new_vars(N, L, St0, Vs) when N > 0 ->
+    {V,St1} = new_var(L, St0),
+    new_vars(N-1, L, St1, [V|Vs]);
+new_vars(0, _L, St, Vs) -> {Vs,St}.
+
 new_var(L, St0) ->
     {New,St1} = new_var_name(St0),
     {{var,L,New},St1}.
@@ -783,18 +827,6 @@ make_list(Ts, Line) ->
 call_error(L, R) ->
     {call,L,{remote,L,{atom,L,erlang},{atom,L,error}},[R]}.
 
-import({Mod,Fs}, St) ->
-    St#exprec{imports=add_imports(Mod, Fs, St#exprec.imports)};
-import(_Mod0, St) ->
-    St.
-
-add_imports(Mod, [F | Fs], Is) ->
-    add_imports(Mod, Fs, orddict:store(F, Mod, Is));
-add_imports(_, [], Is) -> Is.
-
-imported(F, A, St) ->
-    orddict:is_key({F,A}, St#exprec.imports).
-
 %%%
 %%% Replace is_record/3 in guards with matching if possible.
 %%%