diff options
Diffstat (limited to 'lib/compiler')
| -rw-r--r-- | lib/compiler/src/beam_kernel_to_ssa.erl | 167 | ||||
| -rw-r--r-- | lib/compiler/src/beam_ssa.erl | 2 | ||||
| -rw-r--r-- | lib/compiler/src/beam_ssa_codegen.erl | 6 | ||||
| -rw-r--r-- | lib/compiler/src/beam_ssa_opt.erl | 112 | ||||
| -rw-r--r-- | lib/compiler/src/beam_ssa_pre_codegen.erl | 39 |
5 files changed, 208 insertions, 118 deletions
diff --git a/lib/compiler/src/beam_kernel_to_ssa.erl b/lib/compiler/src/beam_kernel_to_ssa.erl index df95749fb3..b2d824b648 100644 --- a/lib/compiler/src/beam_kernel_to_ssa.erl +++ b/lib/compiler/src/beam_kernel_to_ssa.erl @@ -279,7 +279,7 @@ 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 +311,35 @@ 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 +423,7 @@ 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 +441,7 @@ 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 +504,7 @@ 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 +625,7 @@ 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 +638,7 @@ 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 +648,6 @@ 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 +656,7 @@ 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 +666,7 @@ 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), @@ -657,11 +678,12 @@ 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 -> + + case FailCtx of + {no_catch, _} -> {[Call],St2}; - in_catch -> - {TestIs,St} = make_cond_branch(succeeded, [Ret], Fail, St2), + {in_catch, _} -> + {TestIs,St} = make_succeeded(Ret, FailCtx, St2), {[Call|TestIs],St} end end. @@ -748,8 +770,8 @@ 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 +819,7 @@ 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 +835,7 @@ 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 +946,9 @@ 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 +977,14 @@ 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 +992,8 @@ 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 +1002,8 @@ 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 +1012,14 @@ 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 +1027,18 @@ 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 +1048,54 @@ 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 +1105,12 @@ 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}. diff --git a/lib/compiler/src/beam_ssa.erl b/lib/compiler/src/beam_ssa.erl index 7a766623b0..f46cca1431 100644 --- a/lib/compiler/src/beam_ssa.erl +++ b/lib/compiler/src/beam_ssa.erl @@ -101,7 +101,7 @@ 'bs_match' | 'bs_put' | 'bs_start_match' | 'bs_test_tail' | 'bs_utf16_size' | 'bs_utf8_size' | 'build_stacktrace' | 'call' | 'catch_end' | - 'extract' | + 'extract' | 'exception_trampoline' | 'get_hd' | 'get_map_element' | 'get_tl' | 'get_tuple_element' | 'has_map_field' | 'is_nonempty_list' | 'is_tagged_tuple' | diff --git a/lib/compiler/src/beam_ssa_codegen.erl b/lib/compiler/src/beam_ssa_codegen.erl index 7248aca5f3..7102f524d0 100644 --- a/lib/compiler/src/beam_ssa_codegen.erl +++ b/lib/compiler/src/beam_ssa_codegen.erl @@ -965,6 +965,12 @@ cg_block(Is0, Last, Next, St0) -> case Last of #cg_br{succ=Next,fail=Next} -> cg_block(Is0, none, St0); + #cg_br{succ=Same,fail=Same} when Same =:= ?BADARG_BLOCK -> + %% An expression in this block *always* throws an exception, so we + %% terminate it with an 'if_end' to make sure the validator knows + %% that the following instructions won't actually be reached. + {Is,St} = cg_block(Is0, none, St0), + {Is++[if_end],St}; #cg_br{succ=Same,fail=Same} -> {Fail,St1} = use_block_label(Same, St0), {Is,St} = cg_block(Is0, none, St1), diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl index 986be14e8a..f77eeecc94 100644 --- a/lib/compiler/src/beam_ssa_opt.erl +++ b/lib/compiler/src/beam_ssa_opt.erl @@ -901,6 +901,7 @@ cse_suitable(#b_set{}) -> false. -record(fs, {s=undefined :: 'undefined' | 'cleared', regs=#{} :: #{beam_ssa:b_var():=beam_ssa:b_var()}, + vars=cerl_sets:new() :: cerl_sets:set(), fail=none :: 'none' | beam_ssa:label(), non_guards :: gb_sets:set(beam_ssa:label()), bs :: beam_ssa:block_map() @@ -913,22 +914,39 @@ ssa_opt_float({#st{ssa=Linear0,cnt=Count0}=St, FuncDb}) -> {Linear,Count} = float_opt(Linear0, Count0, Fs), {St#st{ssa=Linear,cnt=Count}, FuncDb}. -float_blk_is_in_guard(#b_blk{last=#b_br{fail=F}}, #fs{non_guards=NonGuards}) -> - not gb_sets:is_member(F, NonGuards); -float_blk_is_in_guard(#b_blk{}, #fs{}) -> +%% The fconv instruction doesn't support jumping to a fail label, so we have to +%% skip this optimization if the fail block is a guard. +%% +%% We also skip the optimization in blocks that always fail, as it's both +%% difficult and pointless to rewrite them to use float ops. +float_can_optimize_blk(#b_blk{last=#b_br{bool=#b_var{},fail=F}}, + #fs{non_guards=NonGuards}) -> + gb_sets:is_member(F, NonGuards); +float_can_optimize_blk(#b_blk{}, #fs{}) -> false. +float_opt([{L,#b_blk{is=[#b_set{op=exception_trampoline,args=[Var]}]}=Blk0} | + Bs0], Count0, Fs) -> + %% If we've replaced a BIF with float operations, we'll have a lot of extra + %% blocks that jump to the same failure block, which may have a trampoline + %% that refers to the original operation. + %% + %% Since the point of the trampoline is to keep the BIF from being removed + %% by liveness optimization, we can discard it as the liveness pass leaves + %% floats alone. + Blk = case cerl_sets:is_element(Var, Fs#fs.vars) of + true -> Blk0#b_blk{is=[]}; + false -> Blk0 + end, + {Bs, Count} = float_opt(Bs0, Count0, Fs), + {[{L,Blk}|Bs],Count}; float_opt([{L,Blk}|Bs0], Count0, Fs) -> - case float_blk_is_in_guard(Blk, Fs) of + case float_can_optimize_blk(Blk, Fs) of true -> - %% This block is inside a guard. Don't do - %% any floating point optimizations. - {Bs,Count} = float_opt(Bs0, Count0, Fs), - {[{L,Blk}|Bs],Count}; + float_opt_1(L, Blk, Bs0, Count0, Fs); false -> - %% This block is not inside a guard. - %% We can do the optimization. - float_opt_1(L, Blk, Bs0, Count0, Fs) + {Bs,Count} = float_opt(Bs0, Count0, Fs), + {[{L,Blk}|Bs],Count} end; float_opt([], Count, _Fs) -> {[],Count}. @@ -1007,12 +1025,12 @@ float_maybe_flush(Blk0, #fs{s=cleared,fail=Fail,bs=Blocks}=Fs0, Count0) -> #b_blk{last=#b_br{bool=#b_var{},succ=Succ}=Br} = Blk0, %% If the success block starts with a floating point operation, we can - %% defer flushing to that block as long as it isn't a guard. + %% defer flushing to that block as long as it's suitable for optimization. #b_blk{is=Is} = SuccBlk = map_get(Succ, Blocks), - SuccIsGuard = float_blk_is_in_guard(SuccBlk, Fs0), + CanOptimizeSucc = float_can_optimize_blk(SuccBlk, Fs0), case Is of - [#b_set{anno=#{float_op:=_}}|_] when not SuccIsGuard -> + [#b_set{anno=#{float_op:=_}}|_] when CanOptimizeSucc -> %% No flush needed. {[],Blk0,Fs0,Count0}; _ -> @@ -1068,21 +1086,22 @@ float_opt_is([], Fs, _Count, _Acc) -> none. float_make_op(#b_set{op={bif,Op},dst=Dst,args=As0}=I0, - Ts, #fs{s=S,regs=Rs0}=Fs, Count0) -> + Ts, #fs{s=S,regs=Rs0,vars=Vs0}=Fs, Count0) -> {As1,Rs1,Count1} = float_load(As0, Ts, Rs0, Count0, []), {As,Is0} = unzip(As1), {Fr,Count2} = new_reg('@fr', Count1), FrDst = #b_var{name=Fr}, I = I0#b_set{op={float,Op},dst=FrDst,args=As}, + Vs = cerl_sets:add_element(Dst, Vs0), Rs = Rs1#{Dst=>FrDst}, Is = append(Is0) ++ [I], case S of undefined -> {Ignore,Count} = new_reg('@ssa_ignore', Count2), C = #b_set{op={float,clearerror},dst=#b_var{name=Ignore}}, - {[C|Is],Fs#fs{s=cleared,regs=Rs},Count}; + {[C|Is],Fs#fs{s=cleared,regs=Rs,vars=Vs},Count}; cleared -> - {Is,Fs#fs{regs=Rs},Count2} + {Is,Fs#fs{regs=Rs,vars=Vs},Count2} end. float_load([A|As], [T|Ts], Rs0, Count0, Acc) -> @@ -1211,34 +1230,31 @@ live_opt_is([#b_set{op=phi,dst=Dst}=I|Is], Live, Acc) -> false -> live_opt_is(Is, Live, Acc) end; -live_opt_is([#b_set{op=succeeded,dst=SuccDst=SuccDstVar, - args=[Dst]}=SuccI, - #b_set{dst=Dst}=I|Is], Live0, Acc) -> - case gb_sets:is_member(Dst, Live0) of - true -> - Live1 = gb_sets:add(Dst, Live0), - Live = gb_sets:delete_any(SuccDst, Live1), - live_opt_is([I|Is], Live, [SuccI|Acc]); - false -> - case live_opt_unused(I) of - {replace,NewI0} -> - NewI = NewI0#b_set{dst=SuccDstVar}, - live_opt_is([NewI|Is], Live0, Acc); - keep -> - case gb_sets:is_member(SuccDst, Live0) of - true -> - Live1 = gb_sets:add(Dst, Live0), - Live = gb_sets:delete(SuccDst, Live1), - live_opt_is([I|Is], Live, [SuccI|Acc]); - false -> - live_opt_is([I|Is], Live0, Acc) - end - end +live_opt_is([#b_set{op=succeeded,dst=SuccDst,args=[MapDst]}=SuccI, + #b_set{op=get_map_element,dst=MapDst}=MapI | Is], + Live0, Acc) -> + case {gb_sets:is_member(SuccDst, Live0), + gb_sets:is_member(MapDst, Live0)} of + {true, true} -> + Live = gb_sets:delete(SuccDst, Live0), + live_opt_is([MapI | Is], Live, [SuccI | Acc]); + {true, false} -> + %% 'get_map_element' is unused; replace 'succeeded' with + %% 'has_map_field' + NewI = MapI#b_set{op=has_map_field,dst=SuccDst}, + live_opt_is([NewI | Is], Live0, Acc); + {false, true} -> + %% 'succeeded' is unused (we know it will succeed); discard it and + %% keep 'get_map_element' + live_opt_is([MapI | Is], Live0, Acc); + {false, false} -> + live_opt_is(Is, Live0, Acc) end; live_opt_is([#b_set{dst=Dst}=I|Is], Live0, Acc) -> case gb_sets:is_member(Dst, Live0) of true -> - Live1 = gb_sets:union(Live0, gb_sets:from_ordset(beam_ssa:used(I))), + LiveUsed = gb_sets:from_ordset(beam_ssa:used(I)), + Live1 = gb_sets:union(Live0, LiveUsed), Live = gb_sets:delete(Dst, Live1), live_opt_is(Is, Live, [I|Acc]); false -> @@ -1246,17 +1262,14 @@ live_opt_is([#b_set{dst=Dst}=I|Is], Live0, Acc) -> true -> live_opt_is(Is, Live0, Acc); false -> - Live = gb_sets:union(Live0, gb_sets:from_ordset(beam_ssa:used(I))), + LiveUsed = gb_sets:from_ordset(beam_ssa:used(I)), + Live = gb_sets:union(Live0, LiveUsed), live_opt_is(Is, Live, [I|Acc]) end end; live_opt_is([], Live, Acc) -> {Acc,Live}. -live_opt_unused(#b_set{op=get_map_element}=Set) -> - {replace,Set#b_set{op=has_map_field}}; -live_opt_unused(_) -> keep. - %%% %%% Optimize binary matching. %%% @@ -1942,6 +1955,10 @@ verify_merge_is(_) -> is_merge_allowed(_, #b_blk{}, #b_blk{is=[#b_set{op=peek_message}|_]}) -> false; +is_merge_allowed(_, #b_blk{}, #b_blk{is=[#b_set{op=exception_trampoline}|_]}) -> + false; +is_merge_allowed(_, #b_blk{is=[#b_set{op=exception_trampoline}|_]}, #b_blk{}) -> + false; is_merge_allowed(L, #b_blk{last=#b_br{}}=Blk, #b_blk{}) -> %% The predecessor block must have exactly one successor (L) for %% the merge to be safe. @@ -2040,6 +2057,7 @@ unsuitable_1([{L,#b_blk{is=[#b_set{op=Op}|_]}}|Bs]) -> Unsuitable = case Op of bs_extract -> true; bs_put -> true; + exception_trampoline -> true; {float,_} -> true; landingpad -> true; peek_message -> true; @@ -2248,6 +2266,8 @@ non_guards(Linear) -> non_guards_1([{L,#b_blk{is=Is}}|Bs]) -> case Is of + [#b_set{op=exception_trampoline}|_] -> + [L | non_guards_1(Bs)]; [#b_set{op=landingpad}|_] -> [L | non_guards_1(Bs)]; _ -> diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl index a5fcb91cc0..ee55d55861 100644 --- a/lib/compiler/src/beam_ssa_pre_codegen.erl +++ b/lib/compiler/src/beam_ssa_pre_codegen.erl @@ -120,6 +120,7 @@ passes(Opts) -> %% Preliminaries. ?PASS(fix_bs), + ?PASS(exception_trampolines), ?PASS(sanitize), ?PASS(match_fail_instructions), case FixTuples of @@ -693,6 +694,44 @@ legacy_bs_is([I|Is], Last, IsYreg, Count, Copies, Acc) -> legacy_bs_is([], _Last, _IsYreg, Count, Copies, Acc) -> {reverse(Acc),Count,Copies}. +%% exception_trampolines(St0) -> St. +%% +%% Removes the "exception trampolines" that were added to prevent exceptions +%% from being optimized away. + +exception_trampolines(#st{ssa=Blocks0}=St) -> + RPO = reverse(beam_ssa:rpo(Blocks0)), + Blocks = et_1(RPO, #{}, Blocks0), + St#st{ssa=Blocks}. + +et_1([L | Ls], Trampolines, Blocks) -> + #{ L := #b_blk{is=Is,last=Last0}=Block0 } = Blocks, + case {Is, Last0} of + {[#b_set{op=exception_trampoline}], #b_br{succ=Succ}} -> + et_1(Ls, Trampolines#{ L => Succ }, maps:remove(L, Blocks)); + {_, #b_br{succ=Same,fail=Same}} when Same =:= ?BADARG_BLOCK -> + %% The "badarg block" is just a marker saying that we should raise + %% an exception (= {f,0}) instead of jumping to a particular fail + %% block. Since it's not a reachable block we can't allow + %% unconditional jumps to it except through a trampoline. + error({illegal_jump_to_badarg_block, L}); + {_, #b_br{succ=Succ0,fail=Fail0}} -> + Succ = maps:get(Succ0, Trampolines, Succ0), + Fail = maps:get(Fail0, Trampolines, Fail0), + if + Succ =/= Succ0; Fail =/= Fail0 -> + Last = Last0#b_br{succ=Succ,fail=Fail}, + Block = Block0#b_blk{last=Last}, + et_1(Ls, Trampolines, Blocks#{ L := Block }); + Succ =:= Succ0, Fail =:= Fail0 -> + et_1(Ls, Trampolines, Blocks) + end; + {_, _} -> + et_1(Ls, Trampolines, Blocks) + end; +et_1([], _Trampolines, Blocks) -> + Blocks. + %% sanitize(St0) -> St. %% Remove constructs that can cause problems later: %% |