diff options
Diffstat (limited to 'lib/compiler/src/beam_kernel_to_ssa.erl')
| -rw-r--r-- | lib/compiler/src/beam_kernel_to_ssa.erl | 171 |
1 files changed, 96 insertions, 75 deletions
diff --git a/lib/compiler/src/beam_kernel_to_ssa.erl b/lib/compiler/src/beam_kernel_to_ssa.erl index df95749fb3..2406a634e6 100644 --- a/lib/compiler/src/beam_kernel_to_ssa.erl +++ b/lib/compiler/src/beam_kernel_to_ssa.erl @@ -34,7 +34,7 @@ -type label() :: beam_ssa:label(). %% Main codegen structure. --record(cg, {lcount=1 :: label(), %Label counter +-record(cg, {lcount=1 :: label(), %Label counter bfail=1 :: label(), catch_label=none :: 'none' | label(), vars=#{} :: map(), %Defined variables. @@ -83,6 +83,7 @@ function(#k_fdef{anno=Anno0,func=Name,arity=Arity, cg_fun(Ke, St0) -> {UltimateFail,FailIs,St1} = make_failure(badarg, St0), + ?EXCEPTION_BLOCK = UltimateFail, %Assertion. St2 = St1#cg{bfail=UltimateFail,ultimate_failure=UltimateFail}, {B,St} = cg(Ke, St2), Asm = [{label,0}|B++FailIs], @@ -279,7 +280,7 @@ select_binary(#k_val_clause{val=#k_binary{segs=#k_var{name=Ctx0}},body=B}, #k_var{}=Src, Tf, Vf, St0) -> {Ctx,St1} = new_ssa_var(Ctx0, St0), {Bis0,St2} = match_cg(B, Vf, St1), - {TestIs,St} = make_cond_branch(succeeded, [Ctx], Tf, St2), + {TestIs,St} = make_succeeded(Ctx, {guard, Tf}, St2), Bis1 = [#b_set{op=bs_start_match,dst=Ctx, args=[ssa_arg(Src, St)]}] ++ TestIs ++ Bis0, Bis = finish_bs_matching(Bis1), @@ -311,6 +312,35 @@ make_cond_branch(Cond, Args, Fail, St0) -> make_uncond_branch(Fail) -> #b_br{bool=#b_literal{val=true},succ=Fail,fail=Fail}. +%% +%% The 'succeeded' instruction needs special treatment in catch blocks to +%% prevent the checked operation from being optimized away if a later pass +%% determines that it always fails. +%% + +make_succeeded(Var, {in_catch, CatchLbl}, St0) -> + {Bool, St1} = new_ssa_var('@ssa_bool', St0), + {Succ, St2} = new_label(St1), + {Fail, St} = new_label(St2), + + Check = [#b_set{op=succeeded,dst=Bool,args=[Var]}, + #b_br{bool=Bool,succ=Succ,fail=Fail}], + + %% Add a dummy block that references the checked variable, ensuring it + %% stays alive and that it won't be merged with the landing pad. + Trampoline = [{label,Fail}, + #b_set{op=exception_trampoline,args=[Var]}, + make_uncond_branch(CatchLbl)], + + {Check ++ Trampoline ++ [{label,Succ}], St}; +make_succeeded(Var, {no_catch, Fail}, St) -> + %% Ultimate failure raises an exception, so we must treat it as if it were + %% in a catch to keep it from being optimized out. + #cg{ultimate_failure=Fail} = St, %Assertion + make_succeeded(Var, {in_catch, Fail}, St); +make_succeeded(Var, {guard, Fail}, St) -> + make_cond_branch(succeeded, [Var], Fail, St). + %% Instructions for selection of binary segments. select_bin_segs(Scs, Ivar, Tf, St) -> @@ -394,7 +424,7 @@ select_extract_int(#k_var{name=Tl}, Val, #k_int{val=Sz}, U, Fs, Vf, <<Val:Bits/little>> end, Bits = bit_size(Bin), %Assertion. - {TestIs,St} = make_cond_branch(succeeded, [Dst], Vf, St1), + {TestIs,St} = make_succeeded(Dst, {guard, Vf}, St1), Set = #b_set{op=bs_match,dst=Dst, args=[#b_literal{val=string},Ctx,#b_literal{val=Bin}]}, {[Set|TestIs],St}. @@ -412,7 +442,7 @@ build_bs_instr(Anno, Type, Fail, Ctx, Size, Unit0, Flags0, Dst, St0) -> #b_set{anno=Anno,op=bs_match,dst=Dst, args=[TypeArg,Ctx,Flags]} end, - {Is,St} = make_cond_branch(succeeded, [Dst], Fail, St0), + {Is,St} = make_succeeded(Dst, {guard, Fail}, St0), {[Get|Is],St}. select_val(#k_val_clause{val=#k_tuple{es=Es},body=B}, V, Vf, St0) -> @@ -475,7 +505,7 @@ select_extract_map([P|Ps], Src, Fail, St0) -> Key = ssa_arg(Key0, St0), {Dst,St1} = new_ssa_var(Dst0, St0), Set = #b_set{op=get_map_element,dst=Dst,args=[MapSrc,Key]}, - {TestIs,St2} = make_cond_branch(succeeded, [Dst], Fail, St1), + {TestIs,St2} = make_succeeded(Dst, {guard, Fail}, St1), {Is,St} = select_extract_map(Ps, Src, Fail, St2), {[Set|TestIs]++Is,St}; select_extract_map([], _, _, St) -> @@ -596,7 +626,7 @@ match_fmf(F, LastFail, St0, [H|T]) -> {Rs,St3} = match_fmf(F, LastFail, St2, T), {R ++ [{label,Fail}] ++ Rs,St3}. -%% fail_label(State) -> {Where,FailureLabel}. +%% fail_context(State) -> {Where,FailureLabel}. %% Where = guard | no_catch | in_catch %% Return an indication of which part of a function code is %% being generated for and the appropriate failure label to @@ -609,7 +639,7 @@ match_fmf(F, LastFail, St0, [H|T]) -> %% a try/catch or catch. %% in_catch - In the scope of a try/catch or catch. -fail_label(#cg{catch_label=Catch,bfail=Fail,ultimate_failure=Ult}) -> +fail_context(#cg{catch_label=Catch,bfail=Fail,ultimate_failure=Ult}) -> if Fail =/= Ult -> {guard,Fail}; @@ -619,14 +649,6 @@ fail_label(#cg{catch_label=Catch,bfail=Fail,ultimate_failure=Ult}) -> {in_catch,Catch} end. -%% bif_fail_label(State) -> FailureLabel. -%% Return the appropriate failure label for a guard BIF call or -%% primop that fails. - -bif_fail_label(St) -> - {_,Fail} = fail_label(St), - Fail. - %% call_cg(Func, [Arg], [Ret], Le, State) -> %% {[Ainstr],State}. %% enter_cg(Func, [Arg], Le, St) -> {[Ainstr],St}. @@ -635,7 +657,7 @@ bif_fail_label(St) -> call_cg(Func, As, [], Le, St) -> call_cg(Func, As, [#k_var{name='@ssa_ignored'}], Le, St); call_cg(Func0, As, [#k_var{name=R}|MoreRs]=Rs, Le, St0) -> - case fail_label(St0) of + case fail_context(St0) of {guard,Fail} -> %% Inside a guard. The only allowed function call is to %% erlang:error/1,2. We will generate a branch to the @@ -645,7 +667,7 @@ call_cg(Func0, As, [#k_var{name=R}|MoreRs]=Rs, Le, St0) -> [#k_var{name=DestVar}] = Rs, St = set_ssa_var(DestVar, #b_literal{val=unused}, St0), {[make_uncond_branch(Fail),#cg_unreachable{}],St}; - {Catch,Fail} -> + FailCtx -> %% Ordinary function call in a function body. Args = ssa_args(As, St0), {Ret,St1} = new_ssa_var(R, St0), @@ -657,13 +679,9 @@ call_cg(Func0, As, [#k_var{name=R}|MoreRs]=Rs, Le, St0) -> St2 = foldl(fun(#k_var{name=Dummy}, S) -> set_ssa_var(Dummy, #b_literal{val=unused}, S) end, St1, MoreRs), - case Catch of - no_catch -> - {[Call],St2}; - in_catch -> - {TestIs,St} = make_cond_branch(succeeded, [Ret], Fail, St2), - {[Call|TestIs],St} - end + + {TestIs,St} = make_succeeded(Ret, FailCtx, St2), + {[Call|TestIs],St} end. enter_cg(Func0, As0, Le, St0) -> @@ -748,8 +766,8 @@ bif_cg(Bif, As0, [#k_var{name=Dst0}], Le, St0) -> I = #b_set{anno=line_anno(Le),op={bif,Bif},dst=Dst,args=As}, case erl_bifs:is_safe(erlang, Bif, length(As)) of false -> - Fail = bif_fail_label(St1), - {Is,St} = make_cond_branch(succeeded, [Dst], Fail, St1), + FailCtx = fail_context(St1), + {Is,St} = make_succeeded(Dst, FailCtx, St1), {[I|Is],St}; true-> {[I],St1} @@ -797,7 +815,7 @@ cg_recv_mesg(#k_var{name=R}, Rm, Tl, Le, St0) -> {Dst,St1} = new_ssa_var(R, St0), {Mis,St2} = match_cg(Rm, none, St1), RecvLbl = St1#cg.recv, - {TestIs,St} = make_cond_branch(succeeded, [Dst], Tl, St2), + {TestIs,St} = make_succeeded(Dst, {guard, Tl}, St2), Is = [#b_br{anno=line_anno(Le),bool=#b_literal{val=true}, succ=RecvLbl,fail=RecvLbl}, {label,RecvLbl}, @@ -813,7 +831,7 @@ cg_recv_wait(Te, Es, St0) -> {Tis,St1} = cg(Es, St0), Args = [ssa_arg(Te, St1)], {WaitDst,St2} = new_ssa_var('@ssa_wait', St1), - {WaitIs,St} = make_cond_branch(succeeded, [WaitDst], St1#cg.recv, St2), + {WaitIs,St} = make_succeeded(WaitDst, {guard, St1#cg.recv}, St2), %% Infinite timeout will be optimized later. Is = [#b_set{op=wait_timeout,dst=WaitDst,args=Args}] ++ WaitIs ++ [#b_set{op=timeout}] ++ Tis, @@ -924,9 +942,9 @@ put_cg([#k_var{name=R}], #k_tuple{es=Es}, _Le, St0) -> PutTuple = #b_set{op=put_tuple,dst=Ret,args=Args}, {[PutTuple],St}; put_cg([#k_var{name=R}], #k_binary{segs=Segs}, Le, St0) -> - Fail = bif_fail_label(St0), + FailCtx = fail_context(St0), {Dst,St1} = new_ssa_var(R, St0), - cg_binary(Dst, Segs, Fail, Le, St1); + cg_binary(Dst, Segs, FailCtx, Le, St1); put_cg([#k_var{name=R}], #k_map{op=Op,var=Map, es=[#k_map_pair{key=#k_var{}=K,val=V}]}, Le, St0) -> @@ -955,14 +973,14 @@ put_cg([#k_var{name=R}], Con0, _Le, St0) -> {[],St}. put_cg_map(LineAnno, Op, SrcMap, Dst, List, St0) -> - Fail = bif_fail_label(St0), Args = [#b_literal{val=Op},SrcMap|List], PutMap = #b_set{anno=LineAnno,op=put_map,dst=Dst,args=Args}, if Op =:= assoc -> {[PutMap],St0}; true -> - {Is,St} = make_cond_branch(succeeded, [Dst], Fail, St0), + FailCtx = fail_context(St0), + {Is,St} = make_succeeded(Dst, FailCtx, St0), {[PutMap|Is],St} end. @@ -970,8 +988,8 @@ put_cg_map(LineAnno, Op, SrcMap, Dst, List, St0) -> %%% Code generation for constructing binaries. %%% -cg_binary(Dst, Segs0, Fail, Le, St0) -> - {PutCode0,SzCalc0,St1} = cg_bin_put(Segs0, Fail, St0), +cg_binary(Dst, Segs0, FailCtx, Le, St0) -> + {PutCode0,SzCalc0,St1} = cg_bin_put(Segs0, FailCtx, St0), LineAnno = line_anno(Le), Anno = Le#k.a, case PutCode0 of @@ -980,8 +998,8 @@ cg_binary(Dst, Segs0, Fail, Le, St0) -> {label,_}|_] -> #k_bin_seg{unit=Unit0,next=Segs} = Segs0, Unit = #b_literal{val=Unit0}, - {PutCode,SzCalc1,St2} = cg_bin_put(Segs, Fail, St1), - {_,SzVar,SzCode0,St3} = cg_size_calc(1, SzCalc1, Fail, St2), + {PutCode,SzCalc1,St2} = cg_bin_put(Segs, FailCtx, St1), + {_,SzVar,SzCode0,St3} = cg_size_calc(1, SzCalc1, FailCtx, St2), SzCode = cg_bin_anno(SzCode0, LineAnno), Args = case member(single_use, Anno) of true -> @@ -990,14 +1008,14 @@ cg_binary(Dst, Segs0, Fail, Le, St0) -> [#b_literal{val=append},Src,SzVar,Unit] end, BsInit = #b_set{anno=LineAnno,op=bs_init,dst=Dst,args=Args}, - {TestIs,St} = make_cond_branch(succeeded, [Dst], Fail, St3), + {TestIs,St} = make_succeeded(Dst, FailCtx, St3), {SzCode ++ [BsInit] ++ TestIs ++ PutCode,St}; [#b_set{op=bs_put}|_] -> - {Unit,SzVar,SzCode0,St2} = cg_size_calc(8, SzCalc0, Fail, St1), + {Unit,SzVar,SzCode0,St2} = cg_size_calc(8, SzCalc0, FailCtx, St1), SzCode = cg_bin_anno(SzCode0, LineAnno), Args = [#b_literal{val=new},SzVar,Unit], BsInit = #b_set{anno=LineAnno,op=bs_init,dst=Dst,args=Args}, - {TestIs,St} = make_cond_branch(succeeded, [Dst], Fail, St2), + {TestIs,St} = make_succeeded(Dst, FailCtx, St2), {SzCode ++ [BsInit] ++ TestIs ++ PutCode0,St} end. @@ -1005,18 +1023,18 @@ cg_bin_anno([Set|Sets], Anno) -> [Set#b_set{anno=Anno}|Sets]; cg_bin_anno([], _) -> []. -%% cg_size_calc(PreferredUnit, SzCalc, Fail, St0) -> +%% cg_size_calc(PreferredUnit, SzCalc, FailCtx, St0) -> %% {ActualUnit,SizeVariable,SizeCode,St}. %% Generate size calculation code. -cg_size_calc(Unit, error, _Fail, St) -> +cg_size_calc(Unit, error, _FailCtx, St) -> {#b_literal{val=Unit},#b_literal{val=badarg},[],St}; -cg_size_calc(8, [{1,_}|_]=SzCalc, Fail, St) -> - cg_size_calc(1, SzCalc, Fail, St); -cg_size_calc(8, SzCalc, Fail, St0) -> - {Var,Pre,St} = cg_size_calc_1(SzCalc, Fail, St0), +cg_size_calc(8, [{1,_}|_]=SzCalc, FailCtx, St) -> + cg_size_calc(1, SzCalc, FailCtx, St); +cg_size_calc(8, SzCalc, FailCtx, St0) -> + {Var,Pre,St} = cg_size_calc_1(SzCalc, FailCtx, St0), {#b_literal{val=8},Var,Pre,St}; -cg_size_calc(1, SzCalc0, Fail, St0) -> +cg_size_calc(1, SzCalc0, FailCtx, St0) -> SzCalc = map(fun({8,#b_literal{val=Size}}) -> {1,#b_literal{val=8*Size}}; ({8,{{bif,byte_size},Src}}) -> @@ -1026,54 +1044,54 @@ cg_size_calc(1, SzCalc0, Fail, St0) -> ({_,_}=Pair) -> Pair end, SzCalc0), - {Var,Pre,St} = cg_size_calc_1(SzCalc, Fail, St0), + {Var,Pre,St} = cg_size_calc_1(SzCalc, FailCtx, St0), {#b_literal{val=1},Var,Pre,St}. -cg_size_calc_1(SzCalc, Fail, St0) -> - cg_size_calc_2(SzCalc, #b_literal{val=0}, Fail, St0). +cg_size_calc_1(SzCalc, FailCtx, St0) -> + cg_size_calc_2(SzCalc, #b_literal{val=0}, FailCtx, St0). -cg_size_calc_2([{_,{'*',Unit,{_,_}=Bif}}|T], Sum0, Fail, St0) -> - {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, Fail, St0), - {BifDst,Pre1,St2} = cg_size_bif(Bif, Fail, St1), - {Sum,Pre2,St} = cg_size_add(Sum1, BifDst, Unit, Fail, St2), +cg_size_calc_2([{_,{'*',Unit,{_,_}=Bif}}|T], Sum0, FailCtx, St0) -> + {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, FailCtx, St0), + {BifDst,Pre1,St2} = cg_size_bif(Bif, FailCtx, St1), + {Sum,Pre2,St} = cg_size_add(Sum1, BifDst, Unit, FailCtx, St2), {Sum,Pre0++Pre1++Pre2,St}; -cg_size_calc_2([{_,#b_literal{}=Sz}|T], Sum0, Fail, St0) -> - {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, Fail, St0), - {Sum,Pre,St} = cg_size_add(Sum1, Sz, #b_literal{val=1}, Fail, St1), +cg_size_calc_2([{_,#b_literal{}=Sz}|T], Sum0, FailCtx, St0) -> + {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, FailCtx, St0), + {Sum,Pre,St} = cg_size_add(Sum1, Sz, #b_literal{val=1}, FailCtx, St1), {Sum,Pre0++Pre,St}; -cg_size_calc_2([{_,#b_var{}=Sz}|T], Sum0, Fail, St0) -> - {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, Fail, St0), - {Sum,Pre,St} = cg_size_add(Sum1, Sz, #b_literal{val=1}, Fail, St1), +cg_size_calc_2([{_,#b_var{}=Sz}|T], Sum0, FailCtx, St0) -> + {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, FailCtx, St0), + {Sum,Pre,St} = cg_size_add(Sum1, Sz, #b_literal{val=1}, FailCtx, St1), {Sum,Pre0++Pre,St}; -cg_size_calc_2([{_,{_,_}=Bif}|T], Sum0, Fail, St0) -> - {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, Fail, St0), - {BifDst,Pre1,St2} = cg_size_bif(Bif, Fail, St1), - {Sum,Pre2,St} = cg_size_add(Sum1, BifDst, #b_literal{val=1}, Fail, St2), +cg_size_calc_2([{_,{_,_}=Bif}|T], Sum0, FailCtx, St0) -> + {Sum1,Pre0,St1} = cg_size_calc_2(T, Sum0, FailCtx, St0), + {BifDst,Pre1,St2} = cg_size_bif(Bif, FailCtx, St1), + {Sum,Pre2,St} = cg_size_add(Sum1, BifDst, #b_literal{val=1}, FailCtx, St2), {Sum,Pre0++Pre1++Pre2,St}; -cg_size_calc_2([], Sum, _Fail, St) -> +cg_size_calc_2([], Sum, _FailCtx, St) -> {Sum,[],St}. -cg_size_bif(#b_var{}=Var, _Fail, St) -> +cg_size_bif(#b_var{}=Var, _FailCtx, St) -> {Var,[],St}; -cg_size_bif({Name,Src}, Fail, St0) -> +cg_size_bif({Name,Src}, FailCtx, St0) -> {Dst,St1} = new_ssa_var('@ssa_bif', St0), Bif = #b_set{op=Name,dst=Dst,args=[Src]}, - {TestIs,St} = make_cond_branch(succeeded, [Dst], Fail, St1), + {TestIs,St} = make_succeeded(Dst, FailCtx, St1), {Dst,[Bif|TestIs],St}. -cg_size_add(#b_literal{val=0}, Val, #b_literal{val=1}, _Fail, St) -> +cg_size_add(#b_literal{val=0}, Val, #b_literal{val=1}, _FailCtx, St) -> {Val,[],St}; -cg_size_add(A, B, Unit, Fail, St0) -> +cg_size_add(A, B, Unit, FailCtx, St0) -> {Dst,St1} = new_ssa_var('@ssa_sum', St0), - {TestIs,St} = make_cond_branch(succeeded, [Dst], Fail, St1), + {TestIs,St} = make_succeeded(Dst, FailCtx, St1), BsAdd = #b_set{op=bs_add,dst=Dst,args=[A,B,Unit]}, {Dst,[BsAdd|TestIs],St}. -cg_bin_put(Seg, Fail, St) -> - cg_bin_put_1(Seg, Fail, [], [], St). +cg_bin_put(Seg, FailCtx, St) -> + cg_bin_put_1(Seg, FailCtx, [], [], St). cg_bin_put_1(#k_bin_seg{size=Size0,unit=U,type=T,flags=Fs,seg=Src0,next=Next}, - Fail, Acc, SzCalcAcc, St0) -> + FailCtx, Acc, SzCalcAcc, St0) -> [Src,Size] = ssa_args([Src0,Size0], St0), NeedSize = bs_need_size(T), TypeArg = #b_literal{val=T}, @@ -1083,9 +1101,12 @@ cg_bin_put_1(#k_bin_seg{size=Size0,unit=U,type=T,flags=Fs,seg=Src0,next=Next}, true -> [TypeArg,Flags,Src,Size,Unit]; false -> [TypeArg,Flags,Src] end, - {Is,St} = make_cond_branch(bs_put, Args, Fail, St0), + %% bs_put has its own 'succeeded' logic, and should always jump directly to + %% the fail label regardless of whether it's in a catch or not. + {_, FailLbl} = FailCtx, + {Is,St} = make_cond_branch(bs_put, Args, FailLbl, St0), SzCalc = bin_size_calc(T, Src, Size, U), - cg_bin_put_1(Next, Fail, reverse(Is, Acc), [SzCalc|SzCalcAcc], St); + cg_bin_put_1(Next, FailCtx, reverse(Is, Acc), [SzCalc|SzCalcAcc], St); cg_bin_put_1(#k_bin_end{}, _, Acc, SzCalcAcc, St) -> SzCalc = fold_size_calc(SzCalcAcc, 0, []), {reverse(Acc),SzCalc,St}. |