debugger: Optimize evaluation of new map creation

Make sure that we recognize map literals at load time, as we
do for lists and tuples. Also use maps:from_list/1 to build
a new map instead of building it up from scratch inserting one
key/value pair at the time.

1 files changed, 22 insertions, 10 deletions

diff --git a/lib/debugger/src/dbg_ieval.erl b/lib/debugger/src/dbg_ieval.erl
index 0e176b243f..e6da8409d4 100644
--- a/lib/debugger/src/dbg_ieval.erl
+++ b/lib/debugger/src/dbg_ieval.erl
@@ -650,11 +650,10 @@ expr({tuple,Line,Es0}, Bs0, Ieval) ->
     {value,list_to_tuple(Vs),Bs};
 
 %% Map
-expr({map,Line,Fs0}, Bs0, Ieval) ->
-    {Fs,Bs} = eval_map_fields(Fs0, Bs0, Ieval#ieval{line=Line,top=false}),
-    Value = lists:foldl(fun ({map_assoc,K,V}, Mi) -> maps:put(K,V,Mi) end,
-                        #{}, Fs),
-    {value,Value,Bs};
+expr({map,Line,Fs}, Bs0, Ieval) ->
+    {Map,Bs} = eval_new_map_fields(Fs, Bs0, Ieval#ieval{line=Line,top=false},
+				   fun expr/3),
+    {value,Map,Bs};
 expr({map,Line,E0,Fs0}, Bs0, Ieval0) ->
     Ieval = Ieval0#ieval{line=Line,top=false},
     {value,E,Bs1} = expr(E0, Bs0, Ieval),
@@ -1473,11 +1472,13 @@ guard_expr({cons,_,H0,T0}, Bs) ->
 guard_expr({tuple,_,Es0}, Bs) ->
     {values,Es} = guard_exprs(Es0, Bs),
     {value,list_to_tuple(Es)};
-guard_expr({map,_,Fs0}, Bs) ->
-    Fs = eval_map_fields_guard(Fs0, Bs),
-    Value = lists:foldl(fun ({map_assoc,K,V}, Mi) -> maps:put(K,V,Mi) end,
-                        #{}, Fs),
-    {value,Value};
+guard_expr({map,_,Fs}, Bs0) ->
+    F = fun (G0, B0, _) ->
+		{value,G} = guard_expr(G0, B0),
+		{value,G,B0}
+	end,
+    {Map,_} = eval_new_map_fields(Fs, Bs0, #ieval{top=false}, F),
+    {value,Map};
 guard_expr({map,_,E0,Fs0}, Bs) ->
     {value,E} = guard_expr(E0, Bs),
     Fs = eval_map_fields_guard(Fs0, Bs),
@@ -1526,6 +1527,17 @@ eval_map_fields([{map_field_exact,Line,K0,V0}|Fs], Bs0, Ieval0, F, Acc) ->
 eval_map_fields([], Bs, _Ieval, _F, Acc) ->
     {lists:reverse(Acc),Bs}.
 
+eval_new_map_fields(Fs, Bs0, Ieval, F) ->
+    eval_new_map_fields(Fs, Bs0, Ieval, F, []).
+
+eval_new_map_fields([{Line,K0,V0}|Fs], Bs0, Ieval0, F, Acc) ->
+    Ieval = Ieval0#ieval{line=Line},
+    {value,K,Bs1} = F(K0, Bs0, Ieval),
+    {value,V,Bs2} = F(V0, Bs1, Ieval),
+    eval_new_map_fields(Fs, Bs2, Ieval0, F, [{K,V}|Acc]);
+eval_new_map_fields([], Bs, _, _, Acc) ->
+    {maps:from_list(lists:reverse(Acc)),Bs}.
+
 %% match(Pattern,Term,Bs) -> {match,Bs} | nomatch
 match(Pat, Term, Bs) ->
     try match1(Pat, Term, Bs, Bs)