diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/compiler/src/beam_ssa_pre_codegen.erl | 141 | ||||
| -rw-r--r-- | lib/compiler/test/bs_match_SUITE.erl | 35 |
2 files changed, 108 insertions, 68 deletions
diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl index bad43a9c4e..bf99e8fc26 100644 --- a/lib/compiler/src/beam_ssa_pre_codegen.erl +++ b/lib/compiler/src/beam_ssa_pre_codegen.erl @@ -342,21 +342,22 @@ make_save_point_dict_1([], Ctx, I, Acc) -> [{Ctx,I}|Acc]. bs_restores([{L,#b_blk{is=Is,last=Last}}|Bs], CtxChain, D0, Rs0) -> - FPos = case D0 of - #{L:=Pos0} -> Pos0; - #{} -> #{} - end, - {SPos,Rs} = bs_restores_is(Is, CtxChain, FPos, Rs0), - D = bs_update_successors(Last, SPos, FPos, D0), + InPos = maps:get(L, D0, #{}), + {SuccPos, FailPos, Rs} = bs_restores_is(Is, CtxChain, InPos, InPos, Rs0), + + D = bs_update_successors(Last, SuccPos, FailPos, D0), bs_restores(Bs, CtxChain, D, Rs); bs_restores([], _, _, Rs) -> Rs. bs_update_successors(#b_br{succ=Succ,fail=Fail}, SPos, FPos, D) -> join_positions([{Succ,SPos},{Fail,FPos}], D); -bs_update_successors(#b_switch{fail=Fail,list=List}, SPos, _FPos, D) -> +bs_update_successors(#b_switch{fail=Fail,list=List}, SPos, FPos, D) -> + SPos = FPos, %Assertion. Update = [{L,SPos} || {_,L} <- List] ++ [{Fail,SPos}], join_positions(Update, D); -bs_update_successors(#b_ret{}, _, _, D) -> D. +bs_update_successors(#b_ret{}, SPos, FPos, D) -> + SPos = FPos, %Assertion. + D. join_positions([{L,MapPos0}|T], D) -> case D of @@ -382,75 +383,91 @@ join_positions_1(MapPos0, MapPos1) -> end, MapPos1), maps:merge(MapPos0, MapPos2). +%% +%% Updates the restore and position maps according to the given instructions. +%% +%% Note that positions may be updated even when a match fails; if a match +%% requires a restore, the position at the fail block will be the position +%% we've *restored to* and not the one we entered the current block with. +%% + bs_restores_is([#b_set{op=bs_start_match,dst=Start}|Is], - CtxChain, PosMap0, Rs) -> - PosMap = PosMap0#{Start=>Start}, - bs_restores_is(Is, CtxChain, PosMap, Rs); + CtxChain, SPos0, FPos, Rs) -> + %% We only allow one match per block. + SPos0 = FPos, %Assertion. + SPos = SPos0#{Start=>Start}, + bs_restores_is(Is, CtxChain, SPos, FPos, Rs); bs_restores_is([#b_set{op=bs_match,dst=NewPos,args=Args}=I|Is], - CtxChain, PosMap0, Rs0) -> + CtxChain, SPos0, FPos0, Rs0) -> + SPos0 = FPos0, %Assertion. Start = bs_subst_ctx(NewPos, CtxChain), [_,FromPos|_] = Args, - case PosMap0 of + case SPos0 of #{Start:=FromPos} -> %% Same position, no restore needed. - PosMap = case bs_match_type(I) of + SPos = case bs_match_type(I) of plain -> %% Update position to new position. - PosMap0#{Start:=NewPos}; + SPos0#{Start:=NewPos}; _ -> %% Position will not change (test_unit %% instruction or no instruction at %% all). - PosMap0#{Start:=FromPos} + SPos0#{Start:=FromPos} end, - bs_restores_is(Is, CtxChain, PosMap, Rs0); + bs_restores_is(Is, CtxChain, SPos, FPos0, Rs0); #{Start:=_} -> %% Different positions, might need a restore instruction. case bs_match_type(I) of none -> - %% The tail test will be optimized away. - %% No need to do a restore. - PosMap = PosMap0#{Start:=FromPos}, - bs_restores_is(Is, CtxChain, PosMap, Rs0); + %% This is a tail test that will be optimized away. + %% There's no need to do a restore, and all + %% positions are unchanged. + bs_restores_is(Is, CtxChain, SPos0, FPos0, Rs0); test_unit -> %% This match instruction will be replaced by %% a test_unit instruction. We will need a %% restore. The new position will be the position %% restored to (NOT NewPos). - PosMap = PosMap0#{Start:=FromPos}, + SPos = SPos0#{Start:=FromPos}, + FPos = FPos0#{Start:=FromPos}, Rs = Rs0#{NewPos=>{Start,FromPos}}, - bs_restores_is(Is, CtxChain, PosMap, Rs); + bs_restores_is(Is, CtxChain, SPos, FPos, Rs); plain -> %% Match or skip. Position will be changed. - PosMap = PosMap0#{Start:=NewPos}, + SPos = SPos0#{Start:=NewPos}, + FPos = FPos0#{Start:=FromPos}, Rs = Rs0#{NewPos=>{Start,FromPos}}, - bs_restores_is(Is, CtxChain, PosMap, Rs) + bs_restores_is(Is, CtxChain, SPos, FPos, Rs) end end; bs_restores_is([#b_set{op=bs_extract,args=[FromPos|_]}|Is], - CtxChain, PosMap, Rs) -> + CtxChain, SPos, FPos, Rs) -> Start = bs_subst_ctx(FromPos, CtxChain), - #{Start:=FromPos} = PosMap, %Assertion. - bs_restores_is(Is, CtxChain, PosMap, Rs); + #{Start:=FromPos} = SPos, %Assertion. + #{Start:=FromPos} = FPos, %Assertion. + bs_restores_is(Is, CtxChain, SPos, FPos, Rs); bs_restores_is([#b_set{op=call,dst=Dst,args=Args}|Is], - CtxChain, PosMap0, Rs0) -> - {Rs,PosMap1} = bs_restore_args(Args, PosMap0, CtxChain, Dst, Rs0), - PosMap = bs_invalidate_pos(Args, PosMap1, CtxChain), - bs_restores_is(Is, CtxChain, PosMap, Rs); -bs_restores_is([#b_set{op=landingpad}|Is], CtxChain, PosMap0, Rs) -> + CtxChain, SPos0, FPos0, Rs0) -> + {Rs, SPos1, FPos1} = bs_restore_args(Args, SPos0, FPos0, CtxChain, Dst, Rs0), + {SPos, FPos} = bs_invalidate_pos(Args, SPos1, FPos1, CtxChain), + bs_restores_is(Is, CtxChain, SPos, FPos, Rs); +bs_restores_is([#b_set{op=landingpad}|Is], CtxChain, SPos0, FPos0, Rs) -> %% We can land here from any point, so all positions are invalid. - PosMap = maps:map(fun(_Start,_Pos) -> unknown end, PosMap0), - bs_restores_is(Is, CtxChain, PosMap, Rs); + Invalidate = fun(_Start,_Pos) -> unknown end, + SPos = maps:map(Invalidate, SPos0), + FPos = maps:map(Invalidate, FPos0), + bs_restores_is(Is, CtxChain, SPos, FPos, Rs); bs_restores_is([#b_set{op=Op,dst=Dst,args=Args}|Is], - CtxChain, PosMap0, Rs0) + CtxChain, SPos0, FPos0, Rs0) when Op =:= bs_test_tail; Op =:= bs_get_tail -> - {Rs,PosMap} = bs_restore_args(Args, PosMap0, CtxChain, Dst, Rs0), - bs_restores_is(Is, CtxChain, PosMap, Rs); -bs_restores_is([_|Is], CtxChain, PosMap, Rs) -> - bs_restores_is(Is, CtxChain, PosMap, Rs); -bs_restores_is([], _CtxChain, PosMap, Rs) -> - {PosMap,Rs}. + {Rs, SPos, FPos} = bs_restore_args(Args, SPos0, FPos0, CtxChain, Dst, Rs0), + bs_restores_is(Is, CtxChain, SPos, FPos, Rs); +bs_restores_is([_|Is], CtxChain, SPos, FPos, Rs) -> + bs_restores_is(Is, CtxChain, SPos, FPos, Rs); +bs_restores_is([], _CtxChain, SPos, FPos, Rs) -> + {SPos, FPos, Rs}. bs_match_type(#b_set{args=[#b_literal{val=skip},_Ctx, #b_literal{val=binary},_Flags, @@ -464,40 +481,42 @@ bs_match_type(_) -> %% Call instructions leave the match position in an undefined state, %% requiring us to invalidate each affected argument. -bs_invalidate_pos([#b_var{}=Arg|Args], PosMap0, CtxChain) -> +bs_invalidate_pos([#b_var{}=Arg|Args], SPos0, FPos0, CtxChain) -> Start = bs_subst_ctx(Arg, CtxChain), - case PosMap0 of + case SPos0 of #{Start:=_} -> - PosMap = PosMap0#{Start:=unknown}, - bs_invalidate_pos(Args, PosMap, CtxChain); + SPos = SPos0#{Start:=unknown}, + FPos = FPos0#{Start:=unknown}, + bs_invalidate_pos(Args, SPos, FPos, CtxChain); #{} -> %% Not a match context. - bs_invalidate_pos(Args, PosMap0, CtxChain) + bs_invalidate_pos(Args, SPos0, FPos0, CtxChain) end; -bs_invalidate_pos([_|Args], PosMap, CtxChain) -> - bs_invalidate_pos(Args, PosMap, CtxChain); -bs_invalidate_pos([], PosMap, _CtxChain) -> - PosMap. +bs_invalidate_pos([_|Args], SPos, FPos, CtxChain) -> + bs_invalidate_pos(Args, SPos, FPos, CtxChain); +bs_invalidate_pos([], SPos, FPos, _CtxChain) -> + {SPos, FPos}. -bs_restore_args([#b_var{}=Arg|Args], PosMap0, CtxChain, Dst, Rs0) -> +bs_restore_args([#b_var{}=Arg|Args], SPos0, FPos0, CtxChain, Dst, Rs0) -> Start = bs_subst_ctx(Arg, CtxChain), - case PosMap0 of + case SPos0 of #{Start:=Arg} -> %% Same position, no restore needed. - bs_restore_args(Args, PosMap0, CtxChain, Dst, Rs0); + bs_restore_args(Args, SPos0, FPos0, CtxChain, Dst, Rs0); #{Start:=_} -> %% Different positions, need a restore instruction. - PosMap = PosMap0#{Start:=Arg}, + SPos = SPos0#{Start:=Arg}, + FPos = FPos0#{Start:=Arg}, Rs = Rs0#{Dst=>{Start,Arg}}, - bs_restore_args(Args, PosMap, CtxChain, Dst, Rs); + bs_restore_args(Args, SPos, FPos, CtxChain, Dst, Rs); #{} -> %% Not a match context. - bs_restore_args(Args, PosMap0, CtxChain, Dst, Rs0) + bs_restore_args(Args, SPos0, FPos0, CtxChain, Dst, Rs0) end; -bs_restore_args([_|Args], PosMap, CtxChain, Dst, Rs) -> - bs_restore_args(Args, PosMap, CtxChain, Dst, Rs); -bs_restore_args([], PosMap, _CtxChain, _Dst, Rs) -> - {Rs,PosMap}. +bs_restore_args([_|Args], SPos, FPos, CtxChain, Dst, Rs) -> + bs_restore_args(Args, SPos, FPos, CtxChain, Dst, Rs); +bs_restore_args([], SPos, FPos, _CtxChain, _Dst, Rs) -> + {Rs,SPos,FPos}. %% Insert all bs_save and bs_restore instructions. diff --git a/lib/compiler/test/bs_match_SUITE.erl b/lib/compiler/test/bs_match_SUITE.erl index 41e4918b1e..d97f49c56e 100644 --- a/lib/compiler/test/bs_match_SUITE.erl +++ b/lib/compiler/test/bs_match_SUITE.erl @@ -1891,15 +1891,37 @@ expression_before_match_1(R) -> %% Make sure that context positions are updated on calls. restore_on_call(Config) when is_list(Config) -> - ok = restore_on_call_1(<<0, 1, 2>>). + ok = restore_on_call_plain(<<0, 1, 2>>), + <<"x">> = restore_on_call_match(<<0, "x">>), + ok. -restore_on_call_1(<<0, Rest/binary>>) -> - <<2>> = restore_on_call_2(Rest), - <<2>> = restore_on_call_2(Rest), %% {badmatch, <<>>} on missing restore. +restore_on_call_plain(<<0, Rest/binary>>) -> + <<2>> = restore_on_call_plain_1(Rest), + %% {badmatch, <<>>} on missing restore. + <<2>> = restore_on_call_plain_1(Rest), ok. -restore_on_call_2(<<1, Rest/binary>>) -> Rest; -restore_on_call_2(Other) -> Other. +restore_on_call_plain_1(<<1, Rest/binary>>) -> Rest; +restore_on_call_plain_1(Other) -> Other. + +%% Calls a function that moves the match context passed to it, and then matches +%% on its result to confuse the reposition algorithm's success/fail logic. +restore_on_call_match(<<0, Bin/binary>>) -> + case skip_until_zero(Bin) of + {skipped, Rest} -> + Rest; + not_found -> + %% The match context did not get repositioned before the + %% bs_get_tail instruction here. + Bin + end. + +skip_until_zero(<<0,Rest/binary>>) -> + {skipped, Rest}; +skip_until_zero(<<_C,Rest/binary>>) -> + skip_until_zero(Rest); +skip_until_zero(_) -> + not_found. %% 'catch' must invalidate positions. restore_after_catch(Config) when is_list(Config) -> @@ -1983,5 +2005,4 @@ do_matching_meets_apply(_Bin, {Handler, State}) -> %% Another case of the above. Handler:abs(State). - id(I) -> I. |