diff options
Diffstat (limited to 'lib/compiler/src/v3_codegen.erl')
| -rw-r--r-- | lib/compiler/src/v3_codegen.erl | 204 |
1 files changed, 147 insertions, 57 deletions
diff --git a/lib/compiler/src/v3_codegen.erl b/lib/compiler/src/v3_codegen.erl index b222b25d7c..8189420c1c 100644 --- a/lib/compiler/src/v3_codegen.erl +++ b/lib/compiler/src/v3_codegen.erl @@ -77,10 +77,15 @@ functions(Forms, AtomMod) -> function(#k_fdef{anno=#k{a=Anno},func=Name,arity=Arity, vars=As,body=Kb}, AtomMod, St0) -> try - %% Annotate kernel records with variable usage. #k_match{} = Kb, %Assertion. + + %% Try to suppress the stack frame unless it is + %% really needed. + Body0 = avoid_stack_frame(Kb), + + %% Annotate kernel records with variable usage. Vdb0 = init_vars(As), - {Body,_,Vdb} = body(Kb, 1, Vdb0), + {Body,_,Vdb} = body(Body0, 1, Vdb0), %% Generate the BEAM assembly code. {Asm,EntryLabel,St} = cg_fun(Body, As, Vdb, AtomMod, @@ -88,12 +93,117 @@ function(#k_fdef{anno=#k{a=Anno},func=Name,arity=Arity, Func = {function,Name,Arity,EntryLabel,Asm}, {Func,St} catch - Class:Error -> - Stack = erlang:get_stacktrace(), + Class:Error:Stack -> io:fwrite("Function: ~w/~w\n", [Name,Arity]), erlang:raise(Class, Error, Stack) end. + +%% avoid_stack_frame(Kernel) -> Kernel' +%% If possible, avoid setting up a stack frame. Functions +%% that only do matching, calls to guard BIFs, and tail-recursive +%% calls don't need a stack frame. + +avoid_stack_frame(#k_match{body=Body}=M) -> + try + M#k_match{body=avoid_stack_frame_1(Body)} + catch + impossible -> + M + end. + +avoid_stack_frame_1(#k_alt{first=First0,then=Then0}=Alt) -> + First = avoid_stack_frame_1(First0), + Then = avoid_stack_frame_1(Then0), + Alt#k_alt{first=First,then=Then}; +avoid_stack_frame_1(#k_bif{op=Op}=Bif) -> + case Op of + #k_internal{} -> + %% Most internal BIFs clobber the X registers. + throw(impossible); + _ -> + Bif + end; +avoid_stack_frame_1(#k_break{anno=Anno,args=Args}) -> + #k_guard_break{anno=Anno,args=Args}; +avoid_stack_frame_1(#k_guard_break{}=Break) -> + Break; +avoid_stack_frame_1(#k_enter{}=Enter) -> + %% Tail-recursive calls don't need a stack frame. + Enter; +avoid_stack_frame_1(#k_guard{clauses=Cs0}=Guard) -> + Cs = avoid_stack_frame_list(Cs0), + Guard#k_guard{clauses=Cs}; +avoid_stack_frame_1(#k_guard_clause{guard=G0,body=B0}=C) -> + G = avoid_stack_frame_1(G0), + B = avoid_stack_frame_1(B0), + C#k_guard_clause{guard=G,body=B}; +avoid_stack_frame_1(#k_match{anno=A,vars=Vs,body=B0,ret=Ret}) -> + %% Use #k_guard_match{} instead to avoid saving the X registers + %% to the stack before matching. + B = avoid_stack_frame_1(B0), + #k_guard_match{anno=A,vars=Vs,body=B,ret=Ret}; +avoid_stack_frame_1(#k_guard_match{body=B0}=M) -> + B = avoid_stack_frame_1(B0), + M#k_guard_match{body=B}; +avoid_stack_frame_1(#k_protected{arg=Arg0}=Prot) -> + Arg = avoid_stack_frame_1(Arg0), + Prot#k_protected{arg=Arg}; +avoid_stack_frame_1(#k_put{}=Put) -> + Put; +avoid_stack_frame_1(#k_return{}=Ret) -> + Ret; +avoid_stack_frame_1(#k_select{var=#k_var{anno=Vanno},types=Types0}=Select) -> + case member(reuse_for_context, Vanno) of + false -> + Types = avoid_stack_frame_list(Types0), + Select#k_select{types=Types}; + true -> + %% Including binary patterns that overwrite the register containing + %% the binary with the match context may not be safe. For example, + %% bs_match_SUITE:bin_tail_e/1 with inlining will be rejected by + %% beam_validator. + %% + %% Essentially the following code is produced: + %% + %% bs_match {x,0} => {x,0} + %% ... + %% bs_match {x,0} => {x,1} %% ILLEGAL + %% + %% A bs_match instruction will only accept a match context as the + %% source operand if the source and destination registers are the + %% the same (as in the first bs_match instruction above). + %% The second bs_match instruction is therefore illegal. + %% + %% This situation is avoided if there is a stack frame: + %% + %% move {x,0} => {y,0} + %% bs_match {x,0} => {x,0} + %% ... + %% bs_match {y,0} => {x,1} %% LEGAL + %% + throw(impossible) + end; +avoid_stack_frame_1(#k_seq{arg=A0,body=B0}=Seq) -> + A = avoid_stack_frame_1(A0), + B = avoid_stack_frame_1(B0), + Seq#k_seq{arg=A,body=B}; +avoid_stack_frame_1(#k_test{}=Test) -> + Test; +avoid_stack_frame_1(#k_type_clause{values=Values0}=TC) -> + Values = avoid_stack_frame_list(Values0), + TC#k_type_clause{values=Values}; +avoid_stack_frame_1(#k_val_clause{body=B0}=VC) -> + B = avoid_stack_frame_1(B0), + VC#k_val_clause{body=B}; +avoid_stack_frame_1(_Body) -> + throw(impossible). + +avoid_stack_frame_list([H|T]) -> + [avoid_stack_frame_1(H)|avoid_stack_frame_list(T)]; +avoid_stack_frame_list([]) -> []. + + %% This pass creates beam format annotated with variable lifetime %% information. Each thing is given an index and for each variable we %% store the first and last index for its occurrence. The variable @@ -219,10 +329,8 @@ expr(#k_put{anno=A}=Put, I, _Vdb) -> Put#k_put{anno=#l{i=I,a=A#k.a}}; expr(#k_break{anno=A}=Break, I, _Vdb) -> Break#k_break{anno=#l{i=I,a=A#k.a}}; -expr(#k_guard_break{anno=A}=Break, I, Vdb) -> - Locked = [V || {V,_,_} <- Vdb], - L = #l{i=I,a=A#k.a}, - Break#k_guard_break{anno=L,locked=Locked}; +expr(#k_guard_break{anno=A}=Break, I, _Vdb) -> + Break#k_guard_break{anno=#l{i=I,a=A#k.a}}; expr(#k_return{anno=A}=Ret, I, _Vdb) -> Ret#k_return{anno=#l{i=I,a=A#k.a}}. @@ -246,14 +354,9 @@ match(#k_alt{anno=A,first=Kf,then=Kt}, Ls, I, Vdb0) -> F = match(Kf, Ls, I+1, Vdb1), T = match(Kt, Ls, I+1, Vdb1), #k_alt{anno=[],first=F,then=T}; -match(#k_select{anno=A,var=V,types=Kts}=Select, Ls0, I, Vdb0) -> - Vanno = get_kanno(V), - Ls1 = case member(no_usage, Vanno) of - false -> add_element(V#k_var.name, Ls0); - true -> Ls0 - end, - Vdb1 = use_vars(union(A#k.us, Ls1), I, Vdb0), - Ts = [type_clause(Tc, Ls1, I+1, Vdb1) || Tc <- Kts], +match(#k_select{anno=A,types=Kts}=Select, Ls, I, Vdb0) -> + Vdb1 = use_vars(union(A#k.us, Ls), I, Vdb0), + Ts = [type_clause(Tc, Ls, I+1, Vdb1) || Tc <- Kts], Select#k_select{anno=[],types=Ts}; match(#k_guard{anno=A,clauses=Kcs}, Ls, I, Vdb0) -> Vdb1 = use_vars(union(A#k.us, Ls), I, Vdb0), @@ -388,8 +491,8 @@ cg(#k_return{anno=Le,args=Rs}, Vdb, Bef, St) -> return_cg(Rs, Le, Vdb, Bef, St); cg(#k_break{anno=Le,args=Bs}, Vdb, Bef, St) -> break_cg(Bs, Le, Vdb, Bef, St); -cg(#k_guard_break{anno=Le,args=Bs,locked=N}, Vdb, Bef, St) -> - guard_break_cg(Bs, N, Le, Vdb, Bef, St); +cg(#k_guard_break{anno=Le,args=Bs}, Vdb, Bef, St) -> + guard_break_cg(Bs, Le, Vdb, Bef, St); cg(#cg_need_heap{h=H}, _Vdb, Bef, St) -> {[{test_heap,H,max_reg(Bef#sr.reg)}],Bef,St}. @@ -487,7 +590,10 @@ match_cg(M, Rs, Le, Vdb, Bef, St0) -> guard_match_cg(M, Rs, Le, Vdb, Bef, St0) -> I = Le#l.i, {B,St1} = new_label(St0), - #cg{bfail=Fail} = St1, + Fail = case St0 of + #cg{bfail=0,ultimate_failure=Fail0} -> Fail0; + #cg{bfail=Fail0} -> Fail0 + end, {Mis,Aft,St2} = match_cg(M, Fail, Bef, St1#cg{break=B}), %% Update the register descriptors for the return registers. Reg = guard_match_regs(Aft#sr.reg, Rs), @@ -593,9 +699,6 @@ bsm_rename_ctx(#k_protected{arg=Ts0}=Prot, Old, New, _InProt) -> InProt = true, Ts = bsm_rename_ctx_list(Ts0, Old, New, InProt), bsm_forget_var(Prot#k_protected{arg=Ts}, Old); -bsm_rename_ctx(#k_match{body=Ms0}=Match, Old, New, InProt) -> - Ms = bsm_rename_ctx(Ms0, Old, New, InProt), - Match#k_match{body=Ms}; bsm_rename_ctx(#k_guard_match{body=Ms0}=Match, Old, New, InProt) -> Ms = bsm_rename_ctx(Ms0, Old, New, InProt), Match#k_guard_match{body=Ms}; @@ -612,9 +715,8 @@ bsm_rename_ctx(#cg_block{es=Es0}=Block, Old, New, true) -> %% inside the block. Es = bsm_rename_ctx_list(Es0, Old, New, true), bsm_forget_var(Block#cg_block{es=Es}, Old); -bsm_rename_ctx(#k_guard_break{locked=Locked0}=Break, Old, _New, _InProt) -> - Locked = Locked0 -- [Old], - bsm_forget_var(Break#k_guard_break{locked=Locked}, Old). +bsm_rename_ctx(#k_guard_break{}=Break, Old, _New, _InProt) -> + bsm_forget_var(Break, Old). bsm_rename_ctx_list([C|Cs], Old, New, InProt) -> [bsm_rename_ctx(C, Old, New, InProt)| @@ -1378,8 +1480,6 @@ guard_clause_cg(#k_guard_clause{anno=#l{vdb=Vdb},guard=G,body=B}, Fail, Bef, St0 guard_cg(#k_protected{arg=Ts,ret=Rs,anno=#l{i=I,vdb=Pdb}}, Fail, _Vdb, Bef, St) -> protected_cg(Ts, Rs, Fail, I, Pdb, Bef, St); -guard_cg(#cg_block{es=Ts,anno=#l{i=I,vdb=Bdb}}, Fail, _Vdb, Bef, St) -> - guard_cg_list(Ts, Fail, I, Bdb, Bef, St); guard_cg(#k_test{anno=#l{i=I},op=Test0,args=As,inverted=Inverted}, Fail, Vdb, Bef, St0) -> #k_remote{mod=#k_atom{val=erlang},name=#k_atom{val=Test}} = Test0, @@ -1397,6 +1497,18 @@ guard_cg(G, _Fail, Vdb, Bef, St) -> %%ok = io:fwrite("cg ~w: ~p~n", [?LINE,{Aft}]), {Gis,Aft,St1}. +%% guard_cg_list([Kexpr], Fail, I, Vdb, StackReg, St) -> +%% {[Ainstr],StackReg,St}. + +guard_cg_list(Kes, Fail, I, Vdb, Bef, St0) -> + {Keis,{Aft,St1}} = + flatmapfoldl(fun (Ke, {Inta,Sta}) -> + {Keis,Intb,Stb} = + guard_cg(Ke, Fail, Vdb, Inta, Sta), + {Keis,{Intb,Stb}} + end, {Bef,St0}, need_heap(Kes, I)), + {Keis,Aft,St1}. + %% protected_cg([Kexpr], [Ret], Fail, I, Vdb, Bef, St) -> {[Ainstr],Aft,St}. %% Do a protected. Protecteds without return values are just done %% for effect, the return value is not checked, success passes on to @@ -1453,18 +1565,6 @@ test_cg(Test, As, Fail, I, Vdb, Bef, St) -> Aft = clear_dead(Bef, I, Vdb), {[beam_utils:bif_to_test(Test, Args, {f,Fail})],Aft,St}. -%% guard_cg_list([Kexpr], Fail, I, Vdb, StackReg, St) -> -%% {[Ainstr],StackReg,St}. - -guard_cg_list(Kes, Fail, I, Vdb, Bef, St0) -> - {Keis,{Aft,St1}} = - flatmapfoldl(fun (Ke, {Inta,Sta}) -> - {Keis,Intb,Stb} = - guard_cg(Ke, Fail, Vdb, Inta, Sta), - {Keis,{Intb,Stb}} - end, {Bef,St0}, need_heap(Kes, I)), - {Keis,Aft,St1}. - %% match_fmf(Fun, LastFail, State, [Clause]) -> {Is,Aft,State}. %% This is a special flatmapfoldl for match code gen where we %% generate a "failure" label for each clause. The last clause uses @@ -1685,6 +1785,11 @@ internal_cg(bs_init_writable=I, As, Rs, Le, Vdb, Bef, St) -> {Sis,Int} = cg_setup_call(As, Bef, Le#l.i, Vdb), Reg = load_vars(Rs, clear_regs(Int#sr.reg)), {Sis++[I],clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb),St}; +internal_cg(build_stacktrace=I, As, Rs, Le, Vdb, Bef, St) -> + %% This behaves like a function call. + {Sis,Int} = cg_setup_call(As, Bef, Le#l.i, Vdb), + Reg = load_vars(Rs, clear_regs(Int#sr.reg)), + {Sis++[I],clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb),St}; internal_cg(raise, As, Rs, Le, Vdb, Bef, St) -> %% raise can be treated like a guard BIF. bif_cg(raise, As, Rs, Le, Vdb, Bef, St). @@ -2226,13 +2331,12 @@ break_cg(Bs, Le, Vdb, Bef, St) -> {Ms ++ [{jump,{f,St#cg.break}}], Int#sr{reg=clear_regs(Int#sr.reg)},St}. -guard_break_cg(Bs, Locked, #l{i=I}, Vdb, #sr{reg=Reg0}=Bef, St) -> - RegLocked = get_locked_regs(Reg0, Locked), - #sr{reg=Reg1} = Int = clear_dead(Bef#sr{reg=RegLocked}, I, Vdb), +guard_break_cg(Bs, #l{i=I}, Vdb, #sr{reg=Reg0}=Bef, St) -> + #sr{reg=Reg1} = Int = clear_dead(Bef, I, Vdb), Reg2 = trim_free(Reg1), NumLocked = length(Reg2), Moves0 = gen_moves(Bs, Bef, NumLocked, []), - Moves = order_moves(Moves0, find_scratch_reg(RegLocked)), + Moves = order_moves(Moves0, find_scratch_reg(Reg0)), {BreakVars,_} = mapfoldl(fun(_, RegNum) -> {{RegNum,gbreakvar},RegNum+1} end, length(Reg2), Bs), @@ -2240,20 +2344,6 @@ guard_break_cg(Bs, Locked, #l{i=I}, Vdb, #sr{reg=Reg0}=Bef, St) -> Aft = Int#sr{reg=Reg}, {Moves ++ [{jump,{f,St#cg.break}}],Aft,St}. -get_locked_regs([R|Rs0], Preserve) -> - case {get_locked_regs(Rs0, Preserve),R} of - {[],{_,V}} -> - case lists:member(V, Preserve) of - true -> [R]; - false -> [] - end; - {[],_} -> - []; - {Rs,_} -> - [R|Rs] - end; -get_locked_regs([], _) -> []. - %% cg_reg_arg(Arg0, Info) -> Arg %% cg_reg_args([Arg0], Info) -> [Arg] %% Convert argument[s] into registers. Literal values are returned unchanged. |