From 01835845579e9f0a8da3574864747cd3ba10db6e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Mon, 23 May 2016 20:13:48 +0200 Subject: Simplify beam_utils When beam_utils was first written, it did not have the functions for testing whether a register was not used. Those were added later, in sort of a hacky way. Also, is_killed*() and is_not_used*() for Y registers would return the same answer. Fix that to make the API more consistent (an Y register can only be killed by a deallocate/1 instruction). We will need to change beam_trim to call beam_utils:is_not_used/3 instead of beam_utils:is_killed/3. --- lib/compiler/src/beam_trim.erl | 2 +- lib/compiler/src/beam_utils.erl | 278 +++++++++++++++------------------ lib/compiler/test/beam_utils_SUITE.erl | 6 + 3 files changed, 131 insertions(+), 155 deletions(-) (limited to 'lib') diff --git a/lib/compiler/src/beam_trim.erl b/lib/compiler/src/beam_trim.erl index a8dc6805bc..d40669083e 100644 --- a/lib/compiler/src/beam_trim.erl +++ b/lib/compiler/src/beam_trim.erl @@ -230,7 +230,7 @@ safe_labels([], Acc) -> gb_sets:from_list(Acc). frame_layout(Is, Kills, #st{safe=Safe,lbl=D}) -> N = frame_size(Is, Safe), - IsKilled = fun(R) -> beam_utils:is_killed(R, Is, D) end, + IsKilled = fun(R) -> beam_utils:is_not_used(R, Is, D) end, {N,frame_layout_1(Kills, 0, N, IsKilled, [])}. frame_layout_1([{kill,{y,Y}}=I|Ks], Y, N, IsKilled, Acc) -> diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl index a15ecf633e..c91256f6bc 100644 --- a/lib/compiler/src/beam_utils.erl +++ b/lib/compiler/src/beam_utils.erl @@ -31,8 +31,7 @@ -import(lists, [member/2,sort/1,reverse/1,splitwith/2]). -record(live, - {bl, %Block check fun. - lbl, %Label to code index. + {lbl, %Label to code index. res}). %Result cache for each label. @@ -45,12 +44,16 @@ %% i.e. it is OK to enter the instruction sequence with Register %% containing garbage. -is_killed_block(R, Is) -> - case check_killed_block(R, Is) of - killed -> true; - used -> false; - transparent -> false - end. +is_killed_block({x,X}, [{set,_,_,{alloc,Live,_}}|_]) -> + X >= Live; +is_killed_block(R, [{set,Ds,Ss,_Op}|Is]) -> + not member(R, Ss) andalso (member(R, Ds) orelse is_killed_block(R, Is)); +is_killed_block(R, [{'%live',_,Regs}|Is]) -> + case R of + {x,X} when (Regs bsr X) band 1 =:= 0 -> true; + _ -> is_killed_block(R, Is) + end; +is_killed_block(_, []) -> false. %% is_killed(Register, [Instruction], State) -> true|false %% Determine whether a register is killed by the instruction sequence. @@ -63,20 +66,20 @@ is_killed_block(R, Is) -> %% to determine the kill state across branches. is_killed(R, Is, D) -> - St = #live{bl=check_killed_block_fun(),lbl=D,res=gb_trees:empty()}, + St = #live{lbl=D,res=gb_trees:empty()}, case check_liveness(R, Is, St) of {killed,_} -> true; - {used,_} -> false + {_,_} -> false end. %% is_killed_at(Reg, Lbl, State) -> true|false %% Determine whether Reg is killed at label Lbl. is_killed_at(R, Lbl, D) when is_integer(Lbl) -> - St0 = #live{bl=check_killed_block_fun(),lbl=D,res=gb_trees:empty()}, + St0 = #live{lbl=D,res=gb_trees:empty()}, case check_liveness_at(R, Lbl, St0) of {killed,_} -> true; - {used,_} -> false + {_,_} -> false end. %% is_not_used(Register, [Instruction], State) -> true|false @@ -87,10 +90,10 @@ is_killed_at(R, Lbl, D) when is_integer(Lbl) -> %% across branches. is_not_used(R, Is, D) -> - St = #live{bl=fun check_used_block/3,lbl=D,res=gb_trees:empty()}, + St = #live{lbl=D,res=gb_trees:empty()}, case check_liveness(R, Is, St) of - {killed,_} -> true; - {used,_} -> false + {used,_} -> false; + {_,_} -> true end. %% is_not_used(Register, [Instruction], State) -> true|false @@ -101,10 +104,10 @@ is_not_used(R, Is, D) -> %% across branches. is_not_used_at(R, Lbl, D) -> - St = #live{bl=fun check_used_block/3,lbl=D,res=gb_trees:empty()}, + St = #live{lbl=D,res=gb_trees:empty()}, case check_liveness_at(R, Lbl, St) of - {killed,_} -> true; - {used,_} -> false + {used,_} -> false; + {_,_} -> true end. %% index_labels(FunctionIs) -> State @@ -245,15 +248,19 @@ join_even([S|Ss], [D|Ds]) -> [S,D|join_even(Ss, Ds)]. %% check_liveness(Reg, [Instruction], #live{}) -> -%% {killed | used, #live{}} +%% {killed | not_used | used, #live{}} %% Find out whether Reg is used or killed in instruction sequence. -%% 'killed' means that Reg is assigned a new value or killed by an -%% allocation instruction. 'used' means that Reg is used in some way. +%% +%% killed - Reg is assigned or killed by an allocation instruction. +%% not_used - the value of Reg is not used, but Reg must not be garbage +%% used - Reg is used -check_liveness(R, [{block,Blk}|Is], #live{bl=BlockCheck}=St0) -> - case BlockCheck(R, Blk, St0) of - {transparent,St} -> check_liveness(R, Is, St); - {Other,_}=Res when is_atom(Other) -> Res +check_liveness(R, [{block,Blk}|Is], St0) -> + case check_liveness_block(R, Blk, St0) of + {transparent,St1} -> + check_liveness(R, Is, St1); + {Other,_}=Res when is_atom(Other) -> + Res end; check_liveness(R, [{label,_}|Is], St) -> check_liveness(R, Is, St); @@ -263,8 +270,12 @@ check_liveness(R, [{test,_,{f,Fail},As}|Is], St0) -> {used,St0}; false -> case check_liveness_at(R, Fail, St0) of - {killed,St} -> check_liveness(R, Is, St); - {_,_}=Other -> Other + {killed,St1} -> + check_liveness(R, Is, St1); + {not_used,St1} -> + not_used(check_liveness(R, Is, St1)); + {used,_}=Used -> + Used end end; check_liveness(R, [{test,Op,Fail,Live,Ss,Dst}|Is], St) -> @@ -334,7 +345,7 @@ check_liveness(R, [{call,Live,_}|Is], St) -> case R of {x,X} when X < Live -> {used,St}; {x,_} -> {killed,St}; - {y,_} -> check_liveness(R, Is, St) + {y,_} -> not_used(check_liveness(R, Is, St)) end; check_liveness(R, [{call_ext,Live,_}=I|Is], St) -> case R of @@ -345,7 +356,7 @@ check_liveness(R, [{call_ext,Live,_}=I|Is], St) -> {y,_} -> case beam_jump:is_exit_instruction(I) of false -> - check_liveness(R, Is, St); + not_used(check_liveness(R, Is, St)); true -> %% We must make sure we don't check beyond this %% instruction or we will fall through into random @@ -357,43 +368,20 @@ check_liveness(R, [{call_fun,Live}|Is], St) -> case R of {x,X} when X =< Live -> {used,St}; {x,_} -> {killed,St}; - {y,_} -> check_liveness(R, Is, St) + {y,_} -> not_used(check_liveness(R, Is, St)) end; check_liveness(R, [{apply,Args}|Is], St) -> case R of {x,X} when X < Args+2 -> {used,St}; {x,_} -> {killed,St}; - {y,_} -> check_liveness(R, Is, St) - end; -check_liveness(R, [{bif,Op,{f,Fail},Ss,D}|Is], St0) -> - case check_liveness_fail(R, Op, Ss, Fail, St0) of - {killed,St} = Killed -> - case member(R, Ss) of - true -> {used,St}; - false when R =:= D -> Killed; - false -> check_liveness(R, Is, St) - end; - Other -> - Other - end; -check_liveness(R, [{gc_bif,Op,{f,Fail},Live,Ss,D}|Is], St0) -> - case R of - {x,X} when X >= Live -> - {killed,St0}; - {x,_} -> - {used,St0}; - _ -> - case check_liveness_fail(R, Op, Ss, Fail, St0) of - {killed,St}=Killed -> - case member(R, Ss) of - true -> {used,St}; - false when R =:= D -> Killed; - false -> check_liveness(R, Is, St) - end; - Other -> - Other - end - end; + {y,_} -> not_used(check_liveness(R, Is, St)) + end; +check_liveness(R, [{bif,Op,Fail,Ss,D}|Is], St) -> + Set = {set,[D],Ss,{bif,Op,Fail}}, + check_liveness(R, [{block,[Set]}|Is], St); +check_liveness(R, [{gc_bif,Op,{f,Fail},Live,Ss,D}|Is], St) -> + Set = {set,[D],Ss,{alloc,Live,{gc_bif,Op,Fail}}}, + check_liveness(R, [{block,[Set]}|Is], St); check_liveness(R, [{bs_put,{f,0},_,Ss}|Is], St) -> case member(R, Ss) of true -> {used,St}; @@ -419,7 +407,7 @@ check_liveness(R, [{make_fun2,_,_,_,NumFree}|Is], St) -> case R of {x,X} when X < NumFree -> {used,St}; {x,_} -> {killed,St}; - _ -> check_liveness(R, Is, St) + {y,_} -> not_used(check_liveness(R, Is, St)) end; check_liveness({x,_}=R, [{'catch',_,_}|Is], St) -> %% All x registers will be killed if an exception occurs. @@ -488,18 +476,9 @@ check_liveness(R, [{get_map_elements,{f,Fail},S,{list,L}}|Is], St0) -> Other end end; -check_liveness(R, [{put_map,{f,_},_,Src,_D,Live,{list,_}}|_], St0) -> - case R of - Src -> - {used,St0}; - {x,X} when X < Live -> - {used,St0}; - {x,_} -> - {killed,St0}; - {y,_} -> - %% Conservatively mark it as used. - {used,St0} - end; +check_liveness(R, [{put_map,F,Op,S,D,Live,{list,Puts}}|Is], St) -> + Set = {set,[D],[S|Puts],{alloc,Live,{put_map,Op,F}}}, + check_liveness(R, [{block,[Set]}||Is], St); check_liveness(R, [{test_heap,N,Live}|Is], St) -> I = {block,[{set,[],[],{alloc,Live,{nozero,nostack,N,[]}}}]}, check_liveness(R, [I|Is], St); @@ -512,16 +491,24 @@ check_liveness(R, [{get_list,S,D1,D2}|Is], St) -> check_liveness(_R, Is, St) when is_list(Is) -> %% Not implemented. Conservatively assume that the register is used. {used,St}. - -check_liveness_everywhere(R, [{f,Lbl}|T], St0) -> - case check_liveness_at(R, Lbl, St0) of - {killed,St} -> check_liveness_everywhere(R, T, St); - {_,_}=Other -> Other + +check_liveness_everywhere(R, Lbls, St0) -> + check_liveness_everywhere_1(R, Lbls, killed, St0). + +check_liveness_everywhere_1(R, [{f,Lbl}|T], Res0, St0) -> + {Res1,St} = check_liveness_at(R, Lbl, St0), + Res = case Res1 of + killed -> Res0; + _ -> Res1 + end, + case Res of + used -> {used,St}; + _ -> check_liveness_everywhere_1(R, T, Res, St) end; -check_liveness_everywhere(R, [_|T], St) -> - check_liveness_everywhere(R, T, St); -check_liveness_everywhere(_, [], St) -> - {killed,St}. +check_liveness_everywhere_1(R, [_|T], Res, St) -> + check_liveness_everywhere_1(R, T, Res, St); +check_liveness_everywhere_1(_, [], Res, St) -> + {Res,St}. check_liveness_at(R, Lbl, #live{lbl=Ll,res=ResMemorized}=St0) -> case gb_trees:lookup(Lbl, ResMemorized) of @@ -535,56 +522,20 @@ check_liveness_at(R, Lbl, #live{lbl=Ll,res=ResMemorized}=St0) -> {Res,St#live{res=gb_trees:insert(Lbl, Res, St#live.res)}} end. +not_used({killed,St}) -> {not_used,St}; +not_used({_,_}=Res) -> Res. + check_liveness_ret(R, R, St) -> {used,St}; check_liveness_ret(_, _, St) -> {killed,St}. -check_liveness_fail(_, _, _, 0, St) -> - {killed,St}; -check_liveness_fail(R, Op, Args, Fail, St) -> - Arity = length(Args), - case erl_internal:comp_op(Op, Arity) orelse - erl_internal:new_type_test(Op, Arity) of - true -> {killed,St}; - false -> check_liveness_at(R, Fail, St) - end. - -%% check_killed_block(Reg, [Instruction], State) -> killed | transparent | used -%% Finds out how Reg is used in the instruction sequence inside a block. -%% Returns one of: -%% killed - Reg is assigned a new value or killed by an allocation instruction -%% transparent - Reg is neither used nor killed -%% used - Reg is used or referenced by an allocation instruction. -%% -%% (Unknown instructions will cause an exception.) - -check_killed_block_fun() -> - fun(R, Is, St) -> {check_killed_block(R, Is),St} end. - -check_killed_block({x,X}, [{set,_,_,{alloc,Live,_}}|_]) -> - if - X >= Live -> killed; - true -> used - end; -check_killed_block(R, [{set,Ds,Ss,_Op}|Is]) -> - case member(R, Ss) of - true -> used; - false -> - case member(R, Ds) of - true -> killed; - false -> check_killed_block(R, Is) - end - end; -check_killed_block(R, [{'%live',_,Regs}|Is]) -> - case R of - {x,X} when (Regs bsr X) band 1 =:= 0 -> killed; - _ -> check_killed_block(R, Is) - end; -check_killed_block(_, []) -> transparent. - -%% check_used_block(Reg, [Instruction], State) -> killed | transparent | used +%% check_liveness_block(Reg, [Instruction], State) -> +%% {killed | not_used | used | transparent,State'} %% Finds out how Reg is used in the instruction sequence inside a block. %% Returns one of: -%% killed - Reg is assigned a new value or killed by an allocation instruction +%% killed - Reg is assigned a new value or killed by an +%% allocation instruction +%% not_used - The value is not used, but the register is referenced +%% e.g. by an allocation instruction %% transparent - Reg is neither used nor killed %% used - Reg is explicitly used by an instruction %% @@ -592,45 +543,64 @@ check_killed_block(_, []) -> transparent. %% %% (Unknown instructions will cause an exception.) -check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St) -> +check_liveness_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St0) -> if - X >= Live -> {killed,St}; - true -> check_used_block_1(R, Ss, Ds, Op, Is, St) + X >= Live -> + {killed,St0}; + true -> + case check_liveness_block_1(R, Ss, Ds, Op, Is, St0) of + {killed,St} -> {not_used,St}; + {transparent,St} -> {not_used,St}; + {_,_}=Res -> Res + end end; -check_used_block(R, [{set,Ds,Ss,Op}|Is], St) -> - check_used_block_1(R, Ss, Ds, Op, Is, St); -check_used_block(_, [], St) -> {transparent,St}. +check_liveness_block({y,_}=R, [{set,Ds,Ss,{alloc,_Live,Op}}|Is], St) -> + check_liveness_block_1(R, Ss, Ds, Op, Is, St); +check_liveness_block(R, [{set,Ds,Ss,Op}|Is], St) -> + check_liveness_block_1(R, Ss, Ds, Op, Is, St); +check_liveness_block(_, [], St) -> {transparent,St}. -check_used_block_1(R, Ss, Ds, Op, Is, St0) -> +check_liveness_block_1(R, Ss, Ds, Op, Is, St0) -> case member(R, Ss) of true -> {used,St0}; false -> - case is_reg_used_at(R, Op, St0) of - {true,St} -> - {used,St}; - {false,St} -> + case check_liveness_block_2(R, Op, Ss, St0) of + {killed,St} -> case member(R, Ds) of true -> {killed,St}; - false -> check_used_block(R, Is, St) - end + false -> check_liveness_block(R, Is, St) + end; + {not_used,St} -> + not_used(case member(R, Ds) of + true -> {killed,St}; + false -> check_liveness_block(R, Is, St) + end); + {used,St} -> + {used,St} end end. -is_reg_used_at(R, {gc_bif,_,{f,Lbl}}, St) -> - is_reg_used_at_1(R, Lbl, St); -is_reg_used_at(R, {bif,_,{f,Lbl}}, St) -> - is_reg_used_at_1(R, Lbl, St); -is_reg_used_at(_, _, St) -> - {false,St}. +check_liveness_block_2(R, {gc_bif,_Op,{f,Lbl}}, _Ss, St) -> + check_liveness_block_3(R, Lbl, St); +check_liveness_block_2(R, {bif,Op,{f,Lbl}}, Ss, St) -> + Arity = length(Ss), + case erl_internal:comp_op(Op, Arity) orelse + erl_internal:new_type_test(Op, Arity) of + true -> + {killed,St}; + false -> + check_liveness_block_3(R, Lbl, St) + end; +check_liveness_block_2(R, {put_map,_Op,{f,Lbl}}, _Ss, St) -> + check_liveness_block_3(R, Lbl, St); +check_liveness_block_2(_, _, _, St) -> + {killed,St}. -is_reg_used_at_1(_, 0, St) -> - {false,St}; -is_reg_used_at_1(R, Lbl, St0) -> - case check_liveness_at(R, Lbl, St0) of - {killed,St} -> {false,St}; - {used,St} -> {true,St} - end. +check_liveness_block_3(_, 0, St) -> + {killed,St}; +check_liveness_block_3(R, Lbl, St0) -> + check_liveness_at(R, Lbl, St0). index_labels_1([{label,Lbl}|Is0], Acc) -> Is = drop_labels(Is0), diff --git a/lib/compiler/test/beam_utils_SUITE.erl b/lib/compiler/test/beam_utils_SUITE.erl index f6d4a311bb..5e29f8d7b4 100644 --- a/lib/compiler/test/beam_utils_SUITE.erl +++ b/lib/compiler/test/beam_utils_SUITE.erl @@ -283,6 +283,9 @@ coverage(_Config) -> {'EXIT',{function_clause,_}} = (catch town(overall, {{abc},alcohol})), + self() ! junk_message, + {"url",#{true:="url"}} = appointment(#{"resolution" => "url"}), + ok. %% Cover check_liveness/3. @@ -352,6 +355,9 @@ yellow(Hill) -> Hill, id(42). +do(A, B) -> {A,B}. +appointment(#{"resolution" := Url}) -> + do(receive _ -> Url end, #{true => Url}). %% The identity function. id(I) -> I. -- cgit v1.2.3