From 26940a8c0c37248af03f60dad26133420a01c6d5 Mon Sep 17 00:00:00 2001
From: Anthony Ramine <n.oxyde@gmail.com>
Date: Mon, 29 Jul 2013 00:28:45 +0200
Subject: Lift 'after' blocks to zeroary functions

If 'after' blocks are not lifted, the ids of functions in their bodies
must be killed and it can make stacktraces more confusing than they
should. We lift them to zeroary functions to avoid unnecessary killings
and duplication of code.
---
 lib/compiler/src/v3_core.erl | 42 +++++++++++++++---------------------------
 1 file changed, 15 insertions(+), 27 deletions(-)

(limited to 'lib/compiler')

diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index 8159b42f2f..70822f348e 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -553,16 +553,22 @@ expr({'try',L,Es0,[],[],As0}, St0) ->
     %% 'try ... after ... end'
     {Es1,St1} = exprs(Es0, St0),
     {As1,St2} = exprs(As0, St1),
-    {Evs,Hs0,St3} = try_after(As1, St2),
-    %% We must kill the id for any funs in the duplicated after body,
-    %% to avoid getting two local functions having the same name.
-    Hs = kill_id_anns(Hs0),
+    {Name,St3} = new_fun_name("after", St2),
     {V,St4} = new_var(St3),		% (must not exist in As1)
-    %% TODO: this duplicates the 'after'-code; should lift to function.
-    Lanno = lineno_anno(L, St4),
-    {#itry{anno=#a{anno=Lanno},args=Es1,vars=[V],body=As1++[V],
-	   evars=Evs,handler=Hs},
-     [],St4};
+    LA = lineno_anno(L, St4),
+    Lanno = #a{anno=LA},
+    Fc = function_clause([], LA, {Name,0}),
+    Fun = #ifun{anno=Lanno,id=[],vars=[],
+		clauses=[#iclause{anno=Lanno,pats=[],
+				  guard=[#c_literal{val=true}],
+				  body=As1}],
+		fc=Fc},
+    App = #iapply{anno=Lanno,op=#c_var{anno=LA,name={Name,0}},args=[]},
+    {Evs,Hs,St5} = try_after([App], St4),
+    Try = #itry{anno=Lanno,args=Es1,vars=[V],body=[App,V],evars=Evs,handler=Hs},
+    Letrec = #iletrec{anno=Lanno,defs=[{{Name,0},Fun}],
+		      body=[Try]},
+    {Letrec,[],St5};
 expr({'try',L,Es,Cs,Ecs,As}, St0) ->
     %% 'try ... [of ...] [catch ...] after ... end'
     expr({'try',L,[{'try',L,Es,Cs,Ecs,[]}],[],[],As}, St0);
@@ -2039,24 +2045,6 @@ cexpr(Lit, _As, St) ->
     %%Vs = lit_vars(Lit),
     {set_anno(Lit, Anno#a.anno),[],Vs,St}.
 
-%% Kill the id annotations for any fun inside the expression.
-%% Necessary when duplicating code in try ... after.
-
-kill_id_anns(#ifun{clauses=Cs0}=Fun) ->
-    Cs = kill_id_anns(Cs0),
-    Fun#ifun{clauses=Cs,id=[]};
-kill_id_anns(#a{}=A) ->
-    %% Optimization: Don't waste time searching for funs inside annotations.
-    A;
-kill_id_anns([H|T]) ->
-    [kill_id_anns(H)|kill_id_anns(T)];
-kill_id_anns([]) -> [];
-kill_id_anns(Tuple) when is_tuple(Tuple) ->
-    L0 = tuple_to_list(Tuple),
-    L = kill_id_anns(L0),
-    list_to_tuple(L);
-kill_id_anns(Other) -> Other.
-
 %% lit_vars(Literal) -> [Var].
 
 lit_vars(Lit) -> lit_vars(Lit, []).
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