From cda0f23b62cac146d6afd1467ef96c5d4ad84011 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Fri, 30 Dec 2011 16:54:51 +0100 Subject: 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. --- lib/compiler/src/v3_kernel.erl | 117 ++++++++++++----------------------------- 1 file changed, 34 insertions(+), 83 deletions(-) (limited to 'lib/compiler/src/v3_kernel.erl') 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), -- cgit v1.2.3