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authorBjörn Gustavsson <[email protected]>2014-08-15 15:37:42 +0200
committerBjörn Gustavsson <[email protected]>2014-09-01 12:41:17 +0200
commit81b02eabf162608cba491f1be66dc6226e0aef0c (patch)
tree83061e2f2021c740ddf36e223453d6d5df1e2a38 /lib/compiler/src
parentc56edba2912e12f15226a1e130fdfac25c29b98f (diff)
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sys_core_fold: Eliminate name capture bug
The scope is supposed to contain all variables that are currently live. We need this information for certain optimizations to avoid capturing a name (a name that is in the scope must be renamed; for an example, see move_let_into_expr/2 or any function that calls sub_subst_scope/1). We also use the scope to optimize sub_del_var/2 and sub_is_val/2. When optimizing case expressions, the scope could be reset to an empty list (because sub_new/0 was called instead of sub_new/1). That could cause name capture if inlining was turned on. As simple way to force this bug is to uncomment the "-define(DEBUG, 1)." near the beginning of the file. Without this correction, most files in the test suite fail to compile.
Diffstat (limited to 'lib/compiler/src')
-rw-r--r--lib/compiler/src/sys_core_fold.erl14
1 files changed, 7 insertions, 7 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index ce40213bad..82817a987a 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -2248,23 +2248,23 @@ letify(#c_var{name=Vname}=Var, Val, Body) ->
%% opt_case_in_let(LetExpr) -> LetExpr'
-opt_case_in_let(#c_let{vars=Vs,arg=Arg,body=B}=Let) ->
- opt_case_in_let_0(Vs, Arg, B, Let).
+opt_case_in_let(#c_let{vars=Vs,arg=Arg,body=B}=Let, Sub) ->
+ opt_case_in_let_0(Vs, Arg, B, Let, Sub).
opt_case_in_let_0([#c_var{name=V}], Arg,
- #c_case{arg=#c_var{name=V},clauses=Cs}=Case, Let) ->
+ #c_case{arg=#c_var{name=V},clauses=Cs}=Case, Let, Sub) ->
case opt_case_in_let_1(V, Arg, Cs) of
impossible ->
case is_simple_case_arg(Arg) andalso
not core_lib:is_var_used(V, Case#c_case{arg=#c_literal{val=nil}}) of
true ->
- expr(opt_bool_case(Case#c_case{arg=Arg,clauses=Cs}), sub_new());
+ expr(opt_bool_case(Case#c_case{arg=Arg,clauses=Cs}), sub_new(Sub));
false ->
Let
end;
Expr -> Expr
end;
-opt_case_in_let_0(_, _, _, Let) -> Let.
+opt_case_in_let_0(_, _, _, Let, _) -> Let.
opt_case_in_let_1(V, Arg, Cs) ->
try
@@ -2607,7 +2607,7 @@ opt_simple_let_2(Let0, Vs0, Arg0, Body0, effect, Sub) ->
expr(#c_seq{arg=Arg,body=Body}, effect, sub_new_preserve_types(Sub));
true ->
Let = Let0#c_let{vars=Vs,arg=Arg,body=Body},
- opt_case_in_let_arg(opt_case_in_let(Let), effect, Sub)
+ opt_case_in_let_arg(opt_case_in_let(Let, Sub), effect, Sub)
end
end;
opt_simple_let_2(Let, Vs0, Arg0, Body, value, Sub) ->
@@ -2630,7 +2630,7 @@ opt_simple_let_2(Let, Vs0, Arg0, Body, value, Sub) ->
expr(#c_seq{arg=Arg,body=Body}, value, sub_new_preserve_types(Sub));
{Vs,Arg,Body} ->
opt_case_in_let_arg(
- opt_case_in_let(Let#c_let{vars=Vs,arg=Arg,body=Body}),
+ opt_case_in_let(Let#c_let{vars=Vs,arg=Arg,body=Body}, Sub),
value, Sub)
end.