From 130465c94d6c56e97dab1c1880435e68e57759c7 Mon Sep 17 00:00:00 2001
From: Stavros Aronis <aronisstav@gmail.com>
Date: Wed, 15 Feb 2012 15:47:46 +0100
Subject: Flatten order of dataflow analyses

Dataflow analysis was structured to find SCCs of modules, without making
any use of the information that these were indeed SCCs.
---
 lib/dialyzer/src/dialyzer_callgraph.erl    | 49 +++++++++---------------------
 lib/dialyzer/src/dialyzer_succ_typings.erl | 31 +++----------------
 2 files changed, 19 insertions(+), 61 deletions(-)

(limited to 'lib')

diff --git a/lib/dialyzer/src/dialyzer_callgraph.erl b/lib/dialyzer/src/dialyzer_callgraph.erl
index effd619bde..13eb9418dc 100644
--- a/lib/dialyzer/src/dialyzer_callgraph.erl
+++ b/lib/dialyzer/src/dialyzer_callgraph.erl
@@ -238,33 +238,30 @@ renew_race_info(CG, RaceCode, PublicTables, NamedTables) ->
 modules(#callgraph{digraph = DG}) ->
   ordsets:from_list([M || {M,_F,_A} <- digraph_vertices(DG)]).
 
--spec module_postorder(callgraph()) -> [[module()]].
+-spec module_postorder(callgraph()) -> [module()].
 
 module_postorder(#callgraph{digraph = DG}) ->
-  {MDG, _Nodes} = get_module_digraph_and_nodes(DG),
-  MDG1 = digraph_utils:condensation(MDG),
-  PostOrder = digraph_utils:postorder(MDG1),
-  PostOrder1 = sort_sccs_internally(PostOrder, MDG),
-  digraph:delete(MDG1),
-  digraph_delete(MDG),
-  PostOrder1.
-
-get_module_digraph_and_nodes(DG) ->
   Edges = digraph_edges(DG),
   Nodes = ordsets:from_list([M || {M,_F,_A} <- digraph_vertices(DG)]),
-  MDG = digraph:new(),
-  MDG = digraph_confirm_vertices(Nodes, MDG),
-  MDG = create_module_digraph(Edges, MDG),
-  {MDG, Nodes}.
+  MDG = digraph:new([acyclic]),
+  MDG1 = digraph_confirm_vertices(Nodes, MDG),
+  MDG2 = create_module_digraph(Edges, MDG1),
+  PostOrder = digraph_utils:postorder(MDG2),
+  digraph:delete(MDG2),
+  PostOrder.
 
 %% The module deps of a module are modules that depend on the module
 -spec module_deps(callgraph()) -> dict().
 
 module_deps(#callgraph{digraph = DG}) ->
-  {MDG, Nodes} = get_module_digraph_and_nodes(DG),
-  Deps = [{N, ordsets:from_list(digraph:in_neighbours(MDG, N))}
+  Edges = digraph_edges(DG),
+  Nodes = ordsets:from_list([M || {M,_F,_A} <- digraph_vertices(DG)]),
+  MDG = digraph:new(),
+  MDG1 = digraph_confirm_vertices(Nodes, MDG),
+  MDG2 = create_module_digraph(Edges, MDG1),
+  Deps = [{N, ordsets:from_list(digraph:in_neighbours(MDG2, N))}
 	  || N <- Nodes],
-  digraph_delete(MDG),
+  digraph_delete(MDG2),
   dict:from_list(Deps).
 
 -spec strip_module_deps(dict(), set()) -> dict().
@@ -276,22 +273,6 @@ strip_module_deps(ModDeps, StripSet) ->
   FilterFun2 = fun(_Key, ValSet) -> ValSet =/= [] end,
   dict:filter(FilterFun2, ModDeps1).
 
-sort_sccs_internally(PO, MDG) ->
-  sort_sccs_internally(PO, MDG, []).
-
-sort_sccs_internally([SCC|SCCs], MDG, Acc) ->
-  case SCC of
-    [_, _, _ | _] ->    % length(SCC) >= 3
-      TmpDG = digraph_utils:subgraph(MDG, SCC),
-      NewSCC = digraph_utils:postorder(TmpDG),
-      digraph_delete(TmpDG),
-      sort_sccs_internally(SCCs, MDG, [NewSCC|Acc]);
-    _ ->
-      sort_sccs_internally(SCCs, MDG, [SCC|Acc])
-  end;
-sort_sccs_internally([], _MDG, Acc) ->
-  lists:reverse(Acc).
-
 create_module_digraph([{{M, _, _}, {M, _, _}}|Left], MDG) ->
   create_module_digraph(Left, MDG);
 create_module_digraph([{{M1, _, _}, {M2, _, _}}|Left], MDG) ->
@@ -314,7 +295,7 @@ reset_from_funs(Funs, #callgraph{digraph = DG} = CG) ->
   digraph_delete(SubGraph),
   CG#callgraph{postorder = Postorder}.
 
--spec module_postorder_from_funs([mfa_or_funlbl()], callgraph()) -> [[module()]].
+-spec module_postorder_from_funs([mfa_or_funlbl()], callgraph()) -> [module()].
 
 module_postorder_from_funs(Funs, #callgraph{digraph = DG} = CG) ->
   SubGraph = digraph_reaching_subgraph(Funs, DG),
diff --git a/lib/dialyzer/src/dialyzer_succ_typings.erl b/lib/dialyzer/src/dialyzer_succ_typings.erl
index 5982603b7b..2c2c39951c 100644
--- a/lib/dialyzer/src/dialyzer_succ_typings.erl
+++ b/lib/dialyzer/src/dialyzer_succ_typings.erl
@@ -181,17 +181,13 @@ refine_succ_typings(ModulePostorder, State) ->
   ?debug("Module postorder: ~p\n", [ModulePostorder]),
   refine_succ_typings(ModulePostorder, State, []).
 
-refine_succ_typings([SCC|SCCs], State, Fixpoint) ->
-  Msg = io_lib:format("Dataflow of one SCC: ~w\n", [SCC]),
+refine_succ_typings([M|Rest], State, Fixpoint) ->
+  Msg = io_lib:format("Dataflow of module: ~w\n", [M]),
   send_log(State#st.parent, Msg),
   ?debug("~s\n", [Msg]),
-  {NewState, FixpointFromScc} =
-    case SCC of
-      [M] -> refine_one_module(M, State);
-      [_|_] -> refine_one_scc(SCC, State)
-    end,
+  {NewState, FixpointFromScc} = refine_one_module(M, State),
   NewFixpoint = ordsets:union(Fixpoint, FixpointFromScc),
-  refine_succ_typings(SCCs, NewState, NewFixpoint);
+  refine_succ_typings(Rest, NewState, NewFixpoint);
 refine_succ_typings([], State, Fixpoint) ->
   case Fixpoint =:= [] of
     true -> {fixpoint, State};
@@ -225,25 +221,6 @@ refine_one_module(M, State) ->
 st__renew_state_calls(Callgraph, State) ->
   State#st{callgraph = Callgraph}.
 
-refine_one_scc(SCC, State) ->
-  refine_one_scc(SCC, State, []).
-
-refine_one_scc(SCC, State, AccFixpoint) ->
-  {NewState, FixpointFromScc} = refine_mods_in_scc(SCC, State, []),
-  case FixpointFromScc =:= [] of
-    true -> {NewState, AccFixpoint};
-    false ->
-      NewAccFixpoint = ordsets:union(AccFixpoint, FixpointFromScc),
-      refine_one_scc(SCC, NewState, NewAccFixpoint)
-  end.
-
-refine_mods_in_scc([Mod|Mods], State, Fixpoint) ->
-  {NewState, FixpointFromModule} = refine_one_module(Mod, State),
-  NewFixpoint = ordsets:union(FixpointFromModule, Fixpoint),
-  refine_mods_in_scc(Mods, NewState, NewFixpoint);
-refine_mods_in_scc([], State, Fixpoint) ->
-  {State, Fixpoint}.
-
 reached_fixpoint(OldTypes, NewTypes) ->
   reached_fixpoint(OldTypes, NewTypes, false).
 
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