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authorBjörn Gustavsson <bjorn@erlang.org>2011-12-30 16:54:51 +0100
committerBjörn Gustavsson <bjorn@erlang.org>2012-03-14 11:04:39 +0100
commitcda0f23b62cac146d6afd1467ef96c5d4ad84011 (patch)
treeb3467c538dc456b793949e84c15f5d4b3a137d02 /lib
parentaaa6dd328d6062064295664392e751a6a51ce93e (diff)
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v3_kernel: Clean up handling of guards
Handling of guards become a mess when andalso/orelse in guards were introduced. Clean it up by using common code for most constructs, regardless of where they occur, and when needed use is_in_guard/1 to handle guard constructs differently.
Diffstat (limited to 'lib')
-rw-r--r--lib/compiler/src/v3_kernel.erl117
1 files changed, 34 insertions, 83 deletions
diff --git a/lib/compiler/src/v3_kernel.erl b/lib/compiler/src/v3_kernel.erl
index f6f84c38dc..71d48e7b0d 100644
--- a/lib/compiler/src/v3_kernel.erl
+++ b/lib/compiler/src/v3_kernel.erl
@@ -1418,9 +1418,6 @@ ubody(#ivalues{anno=A,args=As}, {break,_Vbs}, St) ->
false ->
{#k_break{anno=#k{us=Au,ns=[],a=A},args=As},Au,St}
end;
-ubody(#ivalues{anno=A,args=As}, {guard_break,_Vbs}, St) ->
- Au = lit_list_vars(As),
- {#k_guard_break{anno=#k{us=Au,ns=[],a=A},args=As},Au,St};
ubody(E, return, St0) ->
%% Enterable expressions need no trailing return.
case is_enter_expr(E) of
@@ -1437,12 +1434,7 @@ ubody(E, {break,_Rs} = Break, St0) ->
false ->
{Ea,Pa,St1} = force_atomic(E, St0),
ubody(pre_seq(Pa, #ivalues{args=[Ea]}), Break, St1)
- end;
-ubody(E, {guard_break,_Rs} = GuardBreak, St0) ->
- %%ok = io:fwrite("ubody ~w:~p~n", [?LINE,{E,Br}]),
- %% Exiting expressions need no trailing break.
- {Ea,Pa,St1} = force_atomic(E, St0),
- ubody(pre_seq(Pa, #ivalues{args=[Ea]}), GuardBreak, St1).
+ end.
iletrec_funs(#iletrec{defs=Fs}, St0) ->
%% Use union of all free variables.
@@ -1494,66 +1486,21 @@ is_enter_expr(#k_receive{}) -> true;
is_enter_expr(#k_receive_next{}) -> true;
is_enter_expr(_) -> false.
-%% uguard(Expr, State) -> {Expr,[UsedVar],State}.
-%% Tag the guard sequence with its used variables.
-
-uguard(#k_try{anno=A,arg=B0,vars=[#k_var{name=X}],body=#k_var{name=X},
- handler=#k_atom{val=false}}=Try, St0) ->
- {B1,Bu,St1} = uguard(B0, St0),
- {Try#k_try{anno=#k{us=Bu,ns=[],a=A},arg=B1},Bu,St1};
-uguard(T, St) ->
- %%ok = io:fwrite("~w: ~p~n", [?LINE,T]),
- uguard_test(T, St).
-
-%% uguard_test(Expr, State) -> {Test,[UsedVar],State}.
-%% At this stage tests are just expressions which don't return any
-%% values.
-
-uguard_test(T, St) -> uguard_expr(T, [], St).
+%% uexpr(Expr, Break, State) -> {Expr,[UsedVar],State}.
+%% Tag an expression with its used variables.
+%% Break = return | {break,[RetVar]}.
-uguard_expr(#iset{anno=A,vars=Vs,arg=E0,body=B0}, Rs, St0) ->
- Ns = lit_list_vars(Vs),
- {E1,Eu,St1} = uguard_expr(E0, Vs, St0),
- {B1,Bu,St2} = uguard_expr(B0, Rs, St1),
- Used = union(Eu, subtract(Bu, Ns)),
- {#k_seq{anno=#k{us=Used,ns=Ns,a=A},arg=E1,body=B1},Used,St2};
-uguard_expr(#k_try{anno=A,arg=B0,vars=[#k_var{name=X}],body=#k_var{name=X},
- handler=#k_atom{val=false}}=Try, Rs, St0) ->
- {B1,Bu,St1} = uguard_expr(B0, Rs, St0),
- {Try#k_try{anno=#k{us=Bu,ns=lit_list_vars(Rs),a=A},arg=B1,ret=Rs},
- Bu,St1};
-uguard_expr(#k_test{anno=A,op=Op,args=As}=Test, Rs, St) ->
+uexpr(#k_test{anno=A,op=Op,args=As}=Test, {break,Rs}, St) ->
[] = Rs, %Sanity check
Used = union(op_vars(Op), lit_list_vars(As)),
{Test#k_test{anno=#k{us=Used,ns=lit_list_vars(Rs),a=A}},
Used,St};
-uguard_expr(#k_bif{anno=A,op=Op,args=As}=Bif, Rs, St0) ->
- Used = union(op_vars(Op), lit_list_vars(As)),
- {Brs,St1} = bif_returns(Op, Rs, St0),
- {Bif#k_bif{anno=#k{us=Used,ns=lit_list_vars(Brs),a=A},ret=Brs},
- Used,St1};
-uguard_expr(#ivalues{anno=A,args=As}, Rs, St) ->
- Sets = foldr2(fun (V, Arg, Rhs) ->
- #iset{anno=A,vars=[V],arg=Arg,body=Rhs}
- end, #k_atom{val=true}, Rs, As),
- uguard_expr(Sets, [], St);
-uguard_expr(#k_match{anno=A,vars=Vs,body=B0}, Rs, St0) ->
- %% Experimental support for andalso/orelse in guards.
- Br = {guard_break,Rs},
- {B1,Bu,St1} = umatch(B0, Br, St0),
- {#k_guard_match{anno=#k{us=Bu,ns=lit_list_vars(Rs),a=A},
- vars=Vs,body=B1,ret=Rs},Bu,St1};
-uguard_expr(Lit, Rs0, St0) ->
- %% Transform literals to puts here.
- Used = lit_vars(Lit),
- {Rs,St1} = ensure_return_vars(Rs0, St0),
- {#k_put{anno=#k{us=Used,ns=lit_list_vars(Rs),a=get_kanno(Lit)},
- arg=Lit,ret=Rs},Used,St1}.
-
-%% uexpr(Expr, Break, State) -> {Expr,[UsedVar],State}.
-%% Tag an expression with its used variables.
-%% Break = return | {break,[RetVar]}.
-
+uexpr(#iset{anno=A,vars=Vs,arg=E0,body=B0}, {break,_}=Br, St0) ->
+ Ns = lit_list_vars(Vs),
+ {E1,Eu,St1} = uexpr(E0, {break,Vs}, St0),
+ {B1,Bu,St2} = uexpr(B0, Br, St1),
+ Used = union(Eu, subtract(Bu, Ns)),
+ {#k_seq{anno=#k{us=Used,ns=Ns,a=A},arg=E1,body=B1},Used,St2};
uexpr(#k_call{anno=A,op=#k_local{name=F,arity=Ar}=Op,args=As0}=Call, Br, St) ->
Free = get_free(F, Ar, St),
As1 = As0 ++ Free, %Add free variables LAST!
@@ -1606,24 +1553,27 @@ uexpr(#k_receive_accept{anno=A}, _, St) ->
{#k_receive_accept{anno=#k{us=[],ns=[],a=A}},[],St};
uexpr(#k_receive_next{anno=A}, _, St) ->
{#k_receive_next{anno=#k{us=[],ns=[],a=A}},[],St};
-uexpr(#k_try{anno=A,arg=A0,vars=Vs,body=B0,evars=Evs,handler=H0},
- {break,Rs0}, St0) ->
- {Avs,St1} = new_vars(length(Vs), St0), %Need dummy names here
- {A1,Au,St2} = ubody(A0, {break,Avs}, St1), %Must break to clean up here!
- {B1,Bu,St3} = ubody(B0, {break,Rs0}, St2),
- {H1,Hu,St4} = ubody(H0, {break,Rs0}, St3),
- %% Guarantee ONE return variable.
- NumNew = if
- Rs0 =:= [] -> 1;
- true -> 0
- end,
- {Ns,St5} = new_vars(NumNew, St4),
- Rs1 = Rs0 ++ Ns,
- Used = union([Au,subtract(Bu, lit_list_vars(Vs)),
- subtract(Hu, lit_list_vars(Evs))]),
- {#k_try{anno=#k{us=Used,ns=lit_list_vars(Rs1),a=A},
- arg=A1,vars=Vs,body=B1,evars=Evs,handler=H1,ret=Rs1},
- Used,St5};
+uexpr(#k_try{anno=A,arg=A0,vars=Vs,body=B0,evars=Evs,handler=H0}=Try,
+ {break,Rs0}=Br, St0) ->
+ case is_in_guard(St0) of
+ true ->
+ {[#k_var{name=X}],#k_var{name=X}} = {Vs,B0}, %Assertion.
+ #k_atom{val=false} = H0, %Assertion.
+ {A1,Bu,St1} = uexpr(A0, Br, St0),
+ {Try#k_try{anno=#k{us=Bu,ns=lit_list_vars(Rs0),a=A},
+ arg=A1,ret=Rs0},Bu,St1};
+ false ->
+ {Avs,St1} = new_vars(length(Vs), St0),
+ {A1,Au,St2} = ubody(A0, {break,Avs}, St1),
+ {B1,Bu,St3} = ubody(B0, Br, St2),
+ {H1,Hu,St4} = ubody(H0, Br, St3),
+ {Rs1,St5} = ensure_return_vars(Rs0, St4),
+ Used = union([Au,subtract(Bu, lit_list_vars(Vs)),
+ subtract(Hu, lit_list_vars(Evs))]),
+ {#k_try{anno=#k{us=Used,ns=lit_list_vars(Rs1),a=A},
+ arg=A1,vars=Vs,body=B1,evars=Evs,handler=H1,ret=Rs1},
+ Used,St5}
+ end;
uexpr(#k_try{anno=A,arg=A0,vars=Vs,body=B0,evars=Evs,handler=H0},
return, St0) ->
{Avs,St1} = new_vars(length(Vs), St0), %Need dummy names here
@@ -1769,7 +1719,8 @@ umatch(#k_guard{anno=A,clauses=Gs0}, Br, St0) ->
{#k_guard{anno=#k{us=Gus,ns=[],a=A},clauses=Gs1},Gus,St1};
umatch(#k_guard_clause{anno=A,guard=G0,body=B0}, Br, St0) ->
%%ok = io:fwrite("~w: ~p~n", [?LINE,G0]),
- {G1,Gu,St1} = uguard(G0, St0#kern{guard_refc=St0#kern.guard_refc+1}),
+ {G1,Gu,St1} = uexpr(G0, {break,[]},
+ St0#kern{guard_refc=St0#kern.guard_refc+1}),
%%ok = io:fwrite("~w: ~p~n", [?LINE,G1]),
{B1,Bu,St2} = umatch(B0, Br, St1#kern{guard_refc=St1#kern.guard_refc-1}),
Used = union(Gu, Bu),