Support non top level letrecs in dialyzer

Dialyzer so far only supported letrecs at the top-level
and comprehension-like letrecs (i.e. that were directly applied)
in their body.

This commit address this issue by storing in the callgraph
bound letrec labels pointing to their functions. This information
is then used by the dataflow to properly lookup recursive
definitions.

1 files changed, 21 insertions, 6 deletions

diff --git a/lib/dialyzer/src/dialyzer_dep.erl b/lib/dialyzer/src/dialyzer_dep.erl
index febb65b766..1a477f4388 100644
--- a/lib/dialyzer/src/dialyzer_dep.erl
+++ b/lib/dialyzer/src/dialyzer_dep.erl
@@ -39,7 +39,7 @@
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%
-%% analyze(CoreTree) -> {Deps, Esc, Calls}.
+%% analyze(CoreTree) -> {Deps, Esc, Calls, Letrecs}.
 %%
 %% Deps =  a dict mapping labels of functions to an ordset of functions
 %%         it calls.
@@ -53,6 +53,10 @@
 %%         which the operation can refer to. If 'external' is part of
 %%         the set the operation can be externally defined.
 %%
+%% Letrecs = a dict mapping var labels to their recursive definition.
+%%           top-level letrecs are not included as they are handled
+%%           separatedly.
+%%
 
 -spec analyze(cerl:c_module()) -> {dict(), ordset('external' | label()), dict()}.
 
@@ -64,7 +68,8 @@ analyze(Tree) ->
   State1 = state__add_deps(external, output(Esc), State),
   Deps = state__deps(State1),
   Calls = state__calls(State1),
-  {map__finalize(Deps), set__to_ordsets(Esc), map__finalize(Calls)}.
+  Letrecs = state__letrecs(State1),
+  {map__finalize(Deps), set__to_ordsets(Esc), map__finalize(Calls), Letrecs}.
 
 traverse(Tree, Out, State, CurrentFun) ->
   %% io:format("Type: ~w\n", [cerl:type(Tree)]),
@@ -131,9 +136,12 @@ traverse(Tree, Out, State, CurrentFun) ->
     letrec ->
       Defs = cerl:letrec_defs(Tree),
       Body = cerl:letrec_body(Tree),
+      State1 = lists:foldl(fun({ Var, Fun }, Acc) ->
+	state__add_letrecs(cerl_trees:get_label(Var), cerl_trees:get_label(Fun), Acc)
+      end, State, Defs),
       Out1 = bind_defs(Defs, Out),
-      State1 = traverse_defs(Defs, Out1, State, CurrentFun),
-      traverse(Body, Out1, State1, CurrentFun);
+      State2 = traverse_defs(Defs, Out1, State1, CurrentFun),
+      traverse(Body, Out1, State2, CurrentFun);
     literal ->
       {output(none), State};
     module ->
@@ -463,7 +471,8 @@ all_vars(Tree, AccIn) ->
 -record(state, {deps    :: dict(), 
 		esc     :: local_set(), 
 		call    :: dict(), 
-		arities :: dict()}).
+		arities :: dict(),
+		letrecs :: dict()}).
 
 state__new(Tree) ->
   Exports = set__from_list([X || X <- cerl:module_exports(Tree)]),
@@ -471,7 +480,7 @@ state__new(Tree) ->
 			    || {Var, Fun} <- cerl:module_defs(Tree),
 			       set__is_element(Var, Exports)]),
   Arities = cerl_trees:fold(fun find_arities/2, dict:new(), Tree),
-  #state{deps = map__new(), esc = InitEsc, call = map__new(), arities = Arities}.
+  #state{deps = map__new(), esc = InitEsc, call = map__new(), arities = Arities, letrecs = map__new()}.
 
 find_arities(Tree, AccMap) ->
   case cerl:is_c_fun(Tree) of
@@ -490,9 +499,15 @@ state__add_deps(From, #output{type = single, content=To},
   %% io:format("Adding deps from ~w to ~w\n", [From, set__to_ordsets(To)]),
   State#state{deps = map__add(From, To, Map)}.
 
+state__add_letrecs(Var, Fun, #state{letrecs = Map} = State) ->
+  State#state{letrecs = map__store(Var, Fun, Map)}.
+
 state__deps(#state{deps = Deps}) ->
   Deps.
 
+state__letrecs(#state{letrecs = Letrecs}) ->
+  Letrecs.
+
 state__add_esc(#output{content = none}, State) ->
   State;
 state__add_esc(#output{type = single, content = Set},