diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/compiler/src/sys_core_fold.erl | 37 | ||||
| -rw-r--r-- | lib/compiler/test/bs_match_SUITE.erl | 48 |
2 files changed, 73 insertions, 12 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl index f17b0bd130..fbd7452301 100644 --- a/lib/compiler/src/sys_core_fold.erl +++ b/lib/compiler/src/sys_core_fold.erl @@ -2672,16 +2672,19 @@ bsm_nonempty([#c_clause{pats=Ps}|Cs], Pos) -> bsm_nonempty([], _ ) -> false. %% bsm_ensure_no_partition(Cs, Pos) -> ok (exception if problem) -%% We must make sure that binary matching is not partitioned between +%% We must make sure that matching is not partitioned between %% variables like this: %% foo(<<...>>) -> ... -%% foo(Var) when ... -> ... -%% foo(<<...>>) -> +%% foo(<Variable>) when ... -> ... +%% foo(<Any non-variable pattern>) -> %% If there is such partition, we are not allowed to reuse the binary variable -%% for the match context. Also, arguments to the left of the argument that -%% is matched against a binary, are only allowed to be simple variables, not -%% used in guards. The reason is that we must know that the binary is only -%% matched in one place. +%% for the match context. +%% +%% Also, arguments to the left of the argument that is matched +%% against a binary, are only allowed to be simple variables, not +%% used in guards. The reason is that we must know that the binary is +%% only matched in one place (i.e. there must be only one bs_start_match2 +%% instruction emitted). bsm_ensure_no_partition(Cs, Pos) -> bsm_ensure_no_partition_1(Cs, Pos, before). @@ -2689,6 +2692,12 @@ bsm_ensure_no_partition(Cs, Pos) -> %% Loop through each clause. bsm_ensure_no_partition_1([#c_clause{pats=Ps,guard=G}|Cs], Pos, State0) -> State = bsm_ensure_no_partition_2(Ps, Pos, G, simple_vars, State0), + case State of + 'after' -> + bsm_ensure_no_partition_after(Cs, Pos); + _ -> + ok + end, bsm_ensure_no_partition_1(Cs, Pos, State); bsm_ensure_no_partition_1([], _, _) -> ok. @@ -2698,8 +2707,7 @@ bsm_ensure_no_partition_2([#c_binary{}=Where|_], 1, _, Vstate, State) -> before when Vstate =:= simple_vars -> within; before -> bsm_problem(Where, Vstate); within when Vstate =:= simple_vars -> within; - within -> bsm_problem(Where, Vstate); - 'after' -> bsm_problem(Where, bin_partition) + within -> bsm_problem(Where, Vstate) end; bsm_ensure_no_partition_2([#c_alias{}=Alias|_], 1, N, Vstate, State) -> %% Retrieve the real pattern that the alias refers to and check that. @@ -2748,6 +2756,15 @@ bsm_ensure_no_partition_2([#c_var{name=V}|Ps], N, G, Vstate, S) -> bsm_ensure_no_partition_2([_|Ps], N, G, _, S) -> bsm_ensure_no_partition_2(Ps, N-1, G, bin_argument_order, S). +bsm_ensure_no_partition_after([#c_clause{pats=Ps}|Cs], Pos) -> + case nth(Pos, Ps) of + #c_var{} -> + bsm_ensure_no_partition_after(Cs, Pos); + P -> + bsm_problem(P, bin_partition) + end; +bsm_ensure_no_partition_after([], _) -> ok. + bsm_could_match_binary(#c_alias{pat=P}) -> bsm_could_match_binary(P); bsm_could_match_binary(#c_cons{}) -> false; bsm_could_match_binary(#c_tuple{}) -> false; @@ -2872,7 +2889,7 @@ format_error(useless_building) -> format_error(bin_opt_alias) -> "INFO: the '=' operator will prevent delayed sub binary optimization"; format_error(bin_partition) -> - "INFO: non-consecutive clauses that match binaries " + "INFO: matching non-variables after a previous clause matching a variable " "will prevent delayed sub binary optimization"; format_error(bin_left_var_used_in_guard) -> "INFO: a variable to the left of the binary pattern is used in a guard; " diff --git a/lib/compiler/test/bs_match_SUITE.erl b/lib/compiler/test/bs_match_SUITE.erl index d63d2235d7..e8a92c509e 100644 --- a/lib/compiler/test/bs_match_SUITE.erl +++ b/lib/compiler/test/bs_match_SUITE.erl @@ -33,7 +33,8 @@ matching_meets_construction/1,simon/1,matching_and_andalso/1, otp_7188/1,otp_7233/1,otp_7240/1,otp_7498/1, match_string/1,zero_width/1,bad_size/1,haystack/1, - cover_beam_bool/1,matched_out_size/1,follow_fail_branch/1]). + cover_beam_bool/1,matched_out_size/1,follow_fail_branch/1, + no_partition/1]). -export([coverage_id/1,coverage_external_ignore/2]). @@ -57,7 +58,8 @@ groups() -> matching_meets_construction,simon, matching_and_andalso,otp_7188,otp_7233,otp_7240, otp_7498,match_string,zero_width,bad_size,haystack, - cover_beam_bool,matched_out_size,follow_fail_branch]}]. + cover_beam_bool,matched_out_size,follow_fail_branch, + no_partition]}]. init_per_suite(Config) -> @@ -1133,6 +1135,48 @@ ffb_2(<<_,T/bitstring>>, List, A) -> [_|_] -> bit_size(T) end. +no_partition(_) -> + one = no_partition_1(<<"string">>, a1), + {two,<<"string">>} = no_partition_1(<<"string">>, a2), + {two,<<>>} = no_partition_1(<<>>, a2), + {two,a} = no_partition_1(a, a2), + three = no_partition_1(undefined, a3), + {four,a,[]} = no_partition_1([a], a4), + {five,a,b} = no_partition_1({a,b}, a5), + + one = no_partition_2(<<"string">>, a1), + two = no_partition_2(<<"string">>, a2), + two = no_partition_2(<<>>, a2), + two = no_partition_2(a, a2), + three = no_partition_2(undefined, a3), + four = no_partition_2(42, a4), + five = no_partition_2([], a5), + six = no_partition_2(42.0, a6), + ok. + +no_partition_1(<<"string">>, a1) -> + one; +no_partition_1(V, a2) -> + {two,V}; +no_partition_1(undefined, a3) -> + three; +no_partition_1([H|T], a4) -> + {four,H,T}; +no_partition_1({A,B}, a5) -> + {five,A,B}. + +no_partition_2(<<"string">>, a1) -> + one; +no_partition_2(_, a2) -> + two; +no_partition_2(undefined, a3) -> + three; +no_partition_2(42, a4) -> + four; +no_partition_2([], a5) -> + five; +no_partition_2(42.0, a6) -> + six. check(F, R) -> R = F(). |