%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1999-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%% Purpose : Code generator for Beam.
-module(v3_codegen).
%% The main interface.
-export([module/2]).
-import(lists, [member/2,keymember/3,keysort/2,keydelete/3,
append/1,flatmap/2,filter/2,foldl/3,foldr/3,mapfoldl/3,
sort/1,reverse/1,reverse/2,map/2]).
-import(ordsets, [add_element/2,intersection/2,union/2]).
-include("v3_kernel.hrl").
%% These are not defined in v3_kernel.hrl.
get_kanno(Kthing) -> element(2, Kthing).
set_kanno(Kthing, Anno) -> setelement(2, Kthing, Anno).
%% Main codegen structure.
-record(cg, {lcount=1, %Label counter
bfail, %Fail label for BIFs
break, %Break label
recv, %Receive label
is_top_block, %Boolean: top block or not
functable=#{}, %Map of local functions: {Name,Arity}=>Label
in_catch=false, %Inside a catch or not.
need_frame, %Need a stack frame.
ultimate_failure, %Label for ultimate match failure.
ctx %Match context.
}).
%% Stack/register state record.
-record(sr, {reg=[], %Register table
stk=[], %Stack table
res=[]}). %Registers to reserve
%% Internal records.
-record(cg_need_heap, {anno=[] :: term(),
h=0 :: integer()}).
-record(cg_block, {anno=[] :: term(),
es=[] :: [term()]}).
-type vdb_entry() :: {atom(),non_neg_integer(),non_neg_integer()}.
-record(l, {i=0 :: non_neg_integer(), %Op number
vdb=[] :: [vdb_entry()], %Variable database
a=[] :: [term()]}). %Core annotation
-spec module(#k_mdef{}, [compile:option()]) -> {'ok',beam_asm:module_code()}.
module(#k_mdef{name=Mod,exports=Es,attributes=Attr,body=Forms}, _Opts) ->
{Asm,St} = functions(Forms, {atom,Mod}),
{ok,{Mod,Es,Attr,Asm,St#cg.lcount}}.
functions(Forms, AtomMod) ->
mapfoldl(fun (F, St) -> function(F, AtomMod, St) end, #cg{lcount=1}, Forms).
function(#k_fdef{anno=#k{a=Anno},func=Name,arity=Arity,
vars=As,body=Kb}, AtomMod, St0) ->
try
#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(Body0, 1, Vdb0),
%% Generate the BEAM assembly code.
{Asm,EntryLabel,St} = cg_fun(Body, As, Vdb, AtomMod,
{Name,Arity}, Anno, St0),
Func = {function,Name,Arity,EntryLabel,Asm},
{Func,St}
catch
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=#k_call{anno=Anno,op=Op}=Call,
body=#k_break{args=BrArgs0}}=Seq) ->
case Op of
#k_remote{mod=#k_atom{val=Mod},
name=#k_atom{val=Name},
arity=Arity} ->
case erl_bifs:is_exit_bif(Mod, Name, Arity) of
false ->
%% Will clobber X registers. Must have a stack frame.
throw(impossible);
true ->
%% The call to this BIF will never return. It is safe
%% to suppress the stack frame.
Bif = #k_bif{anno=Anno,
op=#k_internal{name=guard_error,arity=1},
args=[Call],ret=[]},
BrArgs = lists:duplicate(length(BrArgs0), #k_nil{}),
GB = #k_guard_break{anno=#k{us=[],ns=[],a=[]},args=BrArgs},
Seq#k_seq{arg=Bif,body=GB}
end;
_ ->
%% Will clobber X registers. Must have a stack frame.
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
%% database, VDB, attached to each thing is only relevant internally
%% for that thing.
%%
%% For nested things like matches the numbering continues locally and
%% the VDB for that thing refers to the variable usage within that
%% thing. Variables which live through a such a thing are internally
%% given a very large last index. Internally the indexes continue
%% after the index of that thing. This creates no problems as the
%% internal variable info never escapes and externally we only see
%% variable which are alive both before or after.
%%
%% This means that variables never "escape" from a thing and the only
%% way to get values from a thing is to "return" them, with 'break' or
%% 'return'. Externally these values become the return values of the
%% thing. This is no real limitation as most nested things have
%% multiple threads so working out a common best variable usage is
%% difficult.
%% body(Kbody, I, Vdb) -> {[Expr],MaxI,Vdb}.
%% Handle a body.
body(#k_seq{arg=Ke,body=Kb}, I, Vdb0) ->
%%ok = io:fwrite("life ~w:~p~n", [?LINE,{Ke,I,Vdb0}]),
A = get_kanno(Ke),
Vdb1 = use_vars(union(A#k.us, A#k.ns), I, Vdb0),
{Es,MaxI,Vdb2} = body(Kb, I+1, Vdb1),
E = expr(Ke, I, Vdb2),
{[E|Es],MaxI,Vdb2};
body(Ke, I, Vdb0) ->
%%ok = io:fwrite("life ~w:~p~n", [?LINE,{Ke,I,Vdb0}]),
A = get_kanno(Ke),
Vdb1 = use_vars(union(A#k.us, A#k.ns), I, Vdb0),
E = expr(Ke, I, Vdb1),
{[E],I,Vdb1}.
%% expr(Kexpr, I, Vdb) -> Expr.
expr(#k_test{anno=A}=Test, I, _Vdb) ->
Test#k_test{anno=#l{i=I,a=A#k.a}};
expr(#k_call{anno=A}=Call, I, _Vdb) ->
Call#k_call{anno=#l{i=I,a=A#k.a}};
expr(#k_enter{anno=A}=Enter, I, _Vdb) ->
Enter#k_enter{anno=#l{i=I,a=A#k.a}};
expr(#k_bif{anno=A}=Bif, I, _Vdb) ->
Bif#k_bif{anno=#l{i=I,a=A#k.a}};
expr(#k_match{anno=A,body=Kb,ret=Rs}, I, Vdb) ->
%% Work out imported variables which need to be locked.
Mdb = vdb_sub(I, I+1, Vdb),
M = match(Kb, A#k.us, I+1, Mdb),
L = #l{i=I,vdb=use_vars(A#k.us, I+1, Mdb),a=A#k.a},
#k_match{anno=L,body=M,ret=Rs};
expr(#k_guard_match{anno=A,body=Kb,ret=Rs}, I, Vdb) ->
%% Work out imported variables which need to be locked.
Mdb = vdb_sub(I, I+1, Vdb),
M = match(Kb, A#k.us, I+1, Mdb),
L = #l{i=I,vdb=use_vars(A#k.us, I+1, Mdb),a=A#k.a},
#k_guard_match{anno=L,body=M,ret=Rs};
expr(#k_protected{}=Protected, I, Vdb) ->
protected(Protected, I, Vdb);
expr(#k_try{anno=A,arg=Ka,vars=Vs,body=Kb,evars=Evs,handler=Kh}=Try, I, Vdb) ->
%% Lock variables that are alive before the catch and used afterwards.
%% Don't lock variables that are only used inside the try.
Tdb0 = vdb_sub(I, I+1, Vdb),
%% This is the tricky bit. Lock variables in Arg that are used in
%% the body and handler. Add try tag 'variable'.
Ab = get_kanno(Kb),
Ah = get_kanno(Kh),
Tdb1 = use_vars(union(Ab#k.us, Ah#k.us), I+3, Tdb0),
Tdb2 = vdb_sub(I, I+2, Tdb1),
Vnames = fun (Kvar) -> Kvar#k_var.name end, %Get the variable names
{Aes,_,Adb} = body(Ka, I+2, add_var({catch_tag,I+1}, I+1, locked, Tdb2)),
{Bes,_,Bdb} = body(Kb, I+4, new_vars(sort(map(Vnames, Vs)), I+3, Tdb2)),
{Hes,_,Hdb} = body(Kh, I+4, new_vars(sort(map(Vnames, Evs)), I+3, Tdb2)),
L = #l{i=I,vdb=Tdb1,a=A#k.a},
Try#k_try{anno=L,
arg=#cg_block{es=Aes,anno=#l{i=I+1,vdb=Adb,a=[]}},
vars=Vs,body=#cg_block{es=Bes,anno=#l{i=I+3,vdb=Bdb,a=[]}},
evars=Evs,handler=#cg_block{es=Hes,anno=#l{i=I+3,vdb=Hdb,a=[]}}};
expr(#k_try_enter{anno=A,arg=Ka,vars=Vs,body=Kb,evars=Evs,handler=Kh}, I, Vdb) ->
%% Lock variables that are alive before the catch and used afterwards.
%% Don't lock variables that are only used inside the try.
Tdb0 = vdb_sub(I, I+1, Vdb),
%% This is the tricky bit. Lock variables in Arg that are used in
%% the body and handler. Add try tag 'variable'.
Ab = get_kanno(Kb),
Ah = get_kanno(Kh),
Tdb1 = use_vars(union(Ab#k.us, Ah#k.us), I+3, Tdb0),
Tdb2 = vdb_sub(I, I+2, Tdb1),
Vnames = fun (Kvar) -> Kvar#k_var.name end, %Get the variable names
{Aes,_,Adb} = body(Ka, I+2, add_var({catch_tag,I+1}, I+1, 1000000, Tdb2)),
{Bes,_,Bdb} = body(Kb, I+4, new_vars(sort(map(Vnames, Vs)), I+3, Tdb2)),
{Hes,_,Hdb} = body(Kh, I+4, new_vars(sort(map(Vnames, Evs)), I+3, Tdb2)),
L = #l{i=I,vdb=Tdb1,a=A#k.a},
#k_try_enter{anno=L,
arg=#cg_block{es=Aes,anno=#l{i=I+1,vdb=Adb,a=[]}},
vars=Vs,body=#cg_block{es=Bes,anno=#l{i=I+3,vdb=Bdb,a=[]}},
evars=Evs,handler=#cg_block{es=Hes,anno=#l{i=I+3,vdb=Hdb,a=[]}}};
expr(#k_catch{anno=A,body=Kb}=Catch, I, Vdb) ->
%% Lock variables that are alive before the catch and used afterwards.
%% Don't lock variables that are only used inside the catch.
%% Add catch tag 'variable'.
Cdb0 = vdb_sub(I, I+1, Vdb),
{Es,_,Cdb1} = body(Kb, I+1, add_var({catch_tag,I}, I, locked, Cdb0)),
L = #l{i=I,vdb=Cdb1,a=A#k.a},
Catch#k_catch{anno=L,body=#cg_block{es=Es}};
expr(#k_receive{anno=A,var=V,body=Kb,action=Ka}=Recv, I, Vdb) ->
%% Work out imported variables which need to be locked.
Rdb = vdb_sub(I, I+1, Vdb),
M = match(Kb, add_element(V#k_var.name, A#k.us), I+1,
new_vars([V#k_var.name], I, Rdb)),
{Tes,_,Adb} = body(Ka, I+1, Rdb),
Le = #l{i=I,vdb=use_vars(A#k.us, I+1, Vdb),a=A#k.a},
Recv#k_receive{anno=Le,body=M,
action=#cg_block{anno=#l{i=I+1,vdb=Adb,a=[]},es=Tes}};
expr(#k_receive_accept{anno=A}, I, _Vdb) ->
#k_receive_accept{anno=#l{i=I,a=A#k.a}};
expr(#k_receive_next{anno=A}, I, _Vdb) ->
#k_receive_next{anno=#l{i=I,a=A#k.a}};
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) ->
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}}.
%% protected(Kprotected, I, Vdb) -> Protected.
%% Only used in guards.
protected(#k_protected{anno=A,arg=Ts}=Prot, I, Vdb) ->
%% Lock variables that are alive before try and used afterwards.
%% Don't lock variables that are only used inside the protected
%% expression.
Pdb0 = vdb_sub(I, I+1, Vdb),
{T,MaxI,Pdb1} = body(Ts, I+1, Pdb0),
Pdb2 = use_vars(A#k.ns, MaxI+1, Pdb1), %Save "return" values
Prot#k_protected{arg=T,anno=#l{i=I,a=A#k.a,vdb=Pdb2}}.
%% match(Kexpr, [LockVar], I, Vdb) -> Expr.
%% Convert match tree to old format.
match(#k_alt{anno=A,first=Kf,then=Kt}, Ls, I, Vdb0) ->
Vdb1 = use_vars(union(A#k.us, 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,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),
Cs = [guard_clause(G, Ls, I+1, Vdb1) || G <- Kcs],
#k_guard{anno=[],clauses=Cs};
match(Other, Ls, I, Vdb0) ->
Vdb1 = use_vars(Ls, I, Vdb0),
{B,_,Vdb2} = body(Other, I+1, Vdb1),
Le = #l{i=I,vdb=Vdb2,a=[]},
#cg_block{anno=Le,es=B}.
type_clause(#k_type_clause{anno=A,type=T,values=Kvs}, Ls, I, Vdb0) ->
%%ok = io:format("life ~w: ~p~n", [?LINE,{T,Kvs}]),
Vdb1 = use_vars(union(A#k.us, Ls), I+1, Vdb0),
Vs = [val_clause(Vc, Ls, I+1, Vdb1) || Vc <- Kvs],
#k_type_clause{anno=[],type=T,values=Vs}.
val_clause(#k_val_clause{anno=A,val=V,body=Kb}, Ls0, I, Vdb0) ->
New = (get_kanno(V))#k.ns,
Bus = (get_kanno(Kb))#k.us,
%%ok = io:format("Ls0 = ~p, Used=~p\n New=~p, Bus=~p\n", [Ls0,Used,New,Bus]),
Ls1 = union(intersection(New, Bus), Ls0), %Lock for safety
Vdb1 = use_vars(union(A#k.us, Ls1), I+1, new_vars(New, I, Vdb0)),
B = match(Kb, Ls1, I+1, Vdb1),
Le = #l{i=I,vdb=use_vars(Bus, I+1, Vdb1),a=A#k.a},
#k_val_clause{anno=Le,val=V,body=B}.
guard_clause(#k_guard_clause{anno=A,guard=Kg,body=Kb}, Ls, I, Vdb0) ->
Vdb1 = use_vars(union(A#k.us, Ls), I+2, Vdb0),
Gdb = vdb_sub(I+1, I+2, Vdb1),
G = protected(Kg, I+1, Gdb),
B = match(Kb, Ls, I+2, Vdb1),
Le = #l{i=I,vdb=use_vars((get_kanno(Kg))#k.us, I+2, Vdb1),a=A#k.a},
#k_guard_clause{anno=Le,guard=G,body=B}.
%% Here follows the code generator pass.
%%
%% The following assumptions have been made:
%%
%% 1. Matches, i.e. things with {match,M,Ret} wrappers, only return
%% values; no variables are exported. If the match would have returned
%% extra variables then these have been transformed to multiple return
%% values.
%%
%% 2. All BIF's called in guards are gc-safe so there is no need to
%% put thing on the stack in the guard. While this would in principle
%% work it would be difficult to keep track of the stack depth when
%% trimming.
%%
%% The code generation uses variable lifetime information added by
%% the previous pass to save variables, allocate registers and
%% move registers to the stack when necessary.
%%
%% We try to use a consistent variable name scheme throughout. The
%% StackReg record is always called Bef,Int<n>,Aft.
%% cg_fun([Lkexpr], [HeadVar], Vdb, State) -> {[Ainstr],State}
cg_fun(Les, Hvs, Vdb, AtomMod, NameArity, Anno, St0) ->
{Fi,St1} = new_label(St0), %FuncInfo label
{Fl,St2} = local_func_label(NameArity, St1),
%%
%% The pattern matching compiler (in v3_kernel) no longer
%% provides its own catch-all clause, because the
%% call to erlang:exit/1 caused problem when cases were
%% used in guards. Therefore, there may be tests that
%% cannot fail (providing that there is not a bug in a
%% previous optimzation pass), but still need to provide
%% a label (there are instructions, such as is_tuple/2,
%% that do not allow {f,0}).
%%
%% We will generate an ultimate failure label and put it
%% at the end of function, followed by an 'if_end' instruction.
%% Note that and 'if_end' instruction does not need any
%% live x registers, so it will always be safe to jump to
%% it. (We never ever expect the jump to be taken, and in
%% most functions there will never be any references to
%% the label in the first place.)
%%
{UltimateMatchFail,St3} = new_label(St2),
%% Create initial stack/register state, clear unused arguments.
Bef = clear_dead(#sr{reg=foldl(fun (#k_var{name=V}, Reg) ->
put_reg(V, Reg)
end, [], Hvs),
stk=[]}, 0, Vdb),
{B,_Aft,St} = cg_list(Les, Vdb, Bef,
St3#cg{bfail=0,
ultimate_failure=UltimateMatchFail,
is_top_block=true}),
{Name,Arity} = NameArity,
Asm = [{label,Fi},line(Anno),{func_info,AtomMod,{atom,Name},Arity},
{label,Fl}|B++[{label,UltimateMatchFail},if_end]],
{Asm,Fl,St}.
%% cg(Lkexpr, Vdb, StackReg, State) -> {[Ainstr],StackReg,State}.
%% Generate code for a kexpr.
cg(#cg_block{anno=Le,es=Es}, Vdb, Bef, St) ->
block_cg(Es, Le, Vdb, Bef, St);
cg(#k_match{anno=Le,body=M,ret=Rs}, Vdb, Bef, St) ->
match_cg(M, Rs, Le, Vdb, Bef, St);
cg(#k_guard_match{anno=Le,body=M,ret=Rs}, Vdb, Bef, St) ->
guard_match_cg(M, Rs, Le, Vdb, Bef, St);
cg(#k_call{anno=Le,op=Func,args=As,ret=Rs}, Vdb, Bef, St) ->
call_cg(Func, As, Rs, Le, Vdb, Bef, St);
cg(#k_enter{anno=Le,op=Func,args=As}, Vdb, Bef, St) ->
enter_cg(Func, As, Le, Vdb, Bef, St);
cg(#k_bif{anno=Le}=Bif, Vdb, Bef, St) ->
bif_cg(Bif, Le, Vdb, Bef, St);
cg(#k_receive{anno=Le,timeout=Te,var=Rvar,body=Rm,action=Tes,ret=Rs},
Vdb, Bef, St) ->
recv_loop_cg(Te, Rvar, Rm, Tes, Rs, Le, Vdb, Bef, St);
cg(#k_receive_next{anno=Le}, Vdb, Bef, St) ->
recv_next_cg(Le, Vdb, Bef, St);
cg(#k_receive_accept{}, _Vdb, Bef, St) ->
{[remove_message],Bef,St};
cg(#k_try{anno=Le,arg=Ta,vars=Vs,body=Tb,evars=Evs,handler=Th,ret=Rs},
Vdb, Bef, St) ->
try_cg(Ta, Vs, Tb, Evs, Th, Rs, Le, Vdb, Bef, St);
cg(#k_try_enter{anno=Le,arg=Ta,vars=Vs,body=Tb,evars=Evs,handler=Th},
Vdb, Bef, St) ->
try_enter_cg(Ta, Vs, Tb, Evs, Th, Le, Vdb, Bef, St);
cg(#k_catch{anno=Le,body=Cb,ret=[R]}, Vdb, Bef, St) ->
catch_cg(Cb, R, Le, Vdb, Bef, St);
cg(#k_put{anno=Le,arg=Con,ret=Var}, Vdb, Bef, St) ->
put_cg(Var, Con, Le, Vdb, Bef, St);
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}, 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}.
%% cg_list([Kexpr], FirstI, Vdb, StackReg, St) -> {[Ainstr],StackReg,St}.
cg_list(Kes, Vdb, Bef, St0) ->
{Keis,{Aft,St1}} =
flatmapfoldl(fun (Ke, {Inta,Sta}) ->
{Keis,Intb,Stb} = cg(Ke, Vdb, Inta, Sta),
{Keis,{Intb,Stb}}
end, {Bef,St0}, need_heap(Kes)),
{Keis,Aft,St1}.
%% need_heap([Lkexpr], I, St) -> [Lkexpr].
%% Insert need_heap instructions in Kexpr list. Try to be smart and
%% collect them together as much as possible.
need_heap(Kes0) ->
{Kes,H} = need_heap_0(reverse(Kes0), 0, []),
%% Prepend need_heap if necessary.
need_heap_need(H) ++ Kes.
need_heap_0([Ke|Kes], H0, Acc) ->
{Ns,H} = need_heap_1(Ke, H0),
need_heap_0(Kes, H, [Ke|Ns]++Acc);
need_heap_0([], H, Acc) ->
{Acc,H}.
need_heap_1(#k_put{arg=#k_binary{}}, H) ->
{need_heap_need(H),0};
need_heap_1(#k_put{arg=#k_map{}}, H) ->
{need_heap_need(H),0};
need_heap_1(#k_put{arg=Val}, H) ->
%% Just pass through adding to needed heap.
{[],H + case Val of
#k_cons{} -> 2;
#k_tuple{es=Es} -> 1 + length(Es);
_Other -> 0
end};
need_heap_1(#k_bif{}=Bif, H) ->
case is_gc_bif(Bif) of
false ->
{[],H};
true ->
{need_heap_need(H),0}
end;
need_heap_1(_Ke, H) ->
%% Call or call-like instruction such as set_tuple_element/3.
{need_heap_need(H),0}.
need_heap_need(0) -> [];
need_heap_need(H) -> [#cg_need_heap{h=H}].
%% is_gc_bif(#k_bif{}) -> true|false.
%% is_gc_bif(Name, Arity) -> true|false.
%% Determines whether the BIF Name/Arity might do a GC.
is_gc_bif(#k_bif{op=#k_remote{name=#k_atom{val=Name}},args=Args}) ->
is_gc_bif(Name, length(Args));
is_gc_bif(#k_bif{op=#k_internal{}}) ->
true.
is_gc_bif(hd, 1) -> false;
is_gc_bif(tl, 1) -> false;
is_gc_bif(self, 0) -> false;
is_gc_bif(node, 0) -> false;
is_gc_bif(node, 1) -> false;
is_gc_bif(element, 2) -> false;
is_gc_bif(get, 1) -> false;
is_gc_bif(tuple_size, 1) -> false;
is_gc_bif(Bif, Arity) ->
not (erl_internal:bool_op(Bif, Arity) orelse
erl_internal:new_type_test(Bif, Arity) orelse
erl_internal:comp_op(Bif, Arity)).
%% match_cg(Matc, [Ret], Le, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
%% Generate code for a match. First save all variables on the stack
%% that are to survive after the match. We leave saved variables in
%% their registers as they might actually be in the right place.
match_cg(M, Rs, Le, Vdb, Bef, St0) ->
I = Le#l.i,
{Sis,Int0} = adjust_stack(Bef, I, I+1, Vdb),
{B,St1} = new_label(St0),
{Mis,Int1,St2} = match_cg(M, St1#cg.ultimate_failure,
Int0, St1#cg{break=B}),
%% Put return values in registers.
Reg = load_vars(Rs, Int1#sr.reg),
{Sis ++ Mis ++ [{label,B}],
clear_dead(Int1#sr{reg=Reg}, I, Vdb),
St2#cg{break=St1#cg.break}}.
guard_match_cg(M, Rs, Le, Vdb, Bef, St0) ->
I = Le#l.i,
{B,St1} = new_label(St0),
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),
{Mis ++ [{label,B}],
clear_dead(Aft#sr{reg=Reg}, I, Vdb),
St2#cg{break=St1#cg.break}}.
guard_match_regs([{I,gbreakvar}|Rs], [#k_var{name=V}|Vs]) ->
[{I,V}|guard_match_regs(Rs, Vs)];
guard_match_regs([R|Rs], Vs) ->
[R|guard_match_regs(Rs, Vs)];
guard_match_regs([], []) -> [].
%% match_cg(Match, Fail, StackReg, State) -> {[Ainstr],StackReg,State}.
%% Generate code for a match tree. N.B. there is no need pass Vdb
%% down as each level which uses this takes its own internal Vdb not
%% the outer one.
match_cg(#k_alt{first=F,then=S}, Fail, Bef, St0) ->
{Tf,St1} = new_label(St0),
{Fis,Faft,St2} = match_cg(F, Tf, Bef, St1),
{Sis,Saft,St3} = match_cg(S, Fail, Bef, St2),
Aft = sr_merge(Faft, Saft),
{Fis ++ [{label,Tf}] ++ Sis,Aft,St3};
match_cg(#k_select{var=#k_var{anno=Vanno,name=Vname}=V,types=Scs0}, Fail, Bef, St) ->
ReuseForContext = member(reuse_for_context, Vanno) andalso
find_reg(Vname, Bef#sr.reg) =/= error,
Scs = case ReuseForContext of
false -> Scs0;
true -> bsm_rename_ctx(Scs0, Vname)
end,
match_fmf(fun (S, F, Sta) ->
select_cg(S, V, F, Fail, Bef, Sta) end,
Fail, St, Scs);
match_cg(#k_guard{clauses=Gcs}, Fail, Bef, St) ->
match_fmf(fun (G, F, Sta) -> guard_clause_cg(G, F, Bef, Sta) end,
Fail, St, Gcs);
match_cg(#cg_block{anno=Le,es=Es}, _Fail, Bef, St) ->
%% Must clear registers and stack of dead variables.
Int = clear_dead(Bef, Le#l.i, Le#l.vdb),
block_cg(Es, Le, Int, St).
%% bsm_rename_ctx([Clause], Var) -> [Clause]
%% We know from an annotation that the register for a binary can
%% be reused for the match context because the two are not truly
%% alive at the same time (even though the life time information
%% says so).
%%
%% The easiest way to have those variables share the same register is
%% to rename the variable with the shortest life-span (the match
%% context) to the variable for the binary (which can have a very
%% long life-time because it is locked during matching). We KNOW that
%% the match state variable will only be alive during the matching.
%%
%% We must also remove all information about the match context
%% variable from all life-time information databases (Vdb).
bsm_rename_ctx([#k_type_clause{type=k_binary,values=Vcs}=TC|Cs], New) ->
[#k_val_clause{val=#k_binary{segs=#k_var{name=Old}}=Bin,
body=Ke0}=VC0] = Vcs,
Ke = bsm_rename_ctx(Ke0, Old, New, false),
VC = VC0#k_val_clause{val=Bin#k_binary{segs=#k_var{name=New}},
body=Ke},
[TC#k_type_clause{values=[VC]}|bsm_rename_ctx(Cs, New)];
bsm_rename_ctx([C|Cs], New) ->
[C|bsm_rename_ctx(Cs, New)];
bsm_rename_ctx([], _) -> [].
%% bsm_rename_ctx(Ke, OldName, NewName, InProt) -> Ke'
%% Rename and clear OldName from life-time information. We must
%% recurse into any block contained in a protected, but it would
%% only complicatate things to recurse into blocks not in a protected
%% (the match context variable is not live inside them).
bsm_rename_ctx(#k_select{var=#k_var{name=V},types=Cs0}=Sel,
Old, New, InProt) ->
Cs = bsm_rename_ctx_list(Cs0, Old, New, InProt),
Sel#k_select{var=#k_var{name=bsm_rename_var(V, Old, New)},types=Cs};
bsm_rename_ctx(#k_type_clause{values=Cs0}=TC, Old, New, InProt) ->
Cs = bsm_rename_ctx_list(Cs0, Old, New, InProt),
TC#k_type_clause{values=Cs};
bsm_rename_ctx(#k_val_clause{body=Ke0}=VC, Old, New, InProt) ->
Ke = bsm_rename_ctx(Ke0, Old, New, InProt),
VC#k_val_clause{body=Ke};
bsm_rename_ctx(#k_alt{first=F0,then=S0}=Alt, Old, New, InProt) ->
F = bsm_rename_ctx(F0, Old, New, InProt),
S = bsm_rename_ctx(S0, Old, New, InProt),
Alt#k_alt{first=F,then=S};
bsm_rename_ctx(#k_guard{clauses=Gcs0}=Guard, Old, New, InProt) ->
Gcs = bsm_rename_ctx_list(Gcs0, Old, New, InProt),
Guard#k_guard{clauses=Gcs};
bsm_rename_ctx(#k_guard_clause{guard=G0,body=B0}=GC, Old, New, InProt) ->
G = bsm_rename_ctx(G0, Old, New, InProt),
B = bsm_rename_ctx(B0, Old, New, InProt),
%% A guard clause may cause unsaved variables to be saved on the stack.
%% Since the match state variable Old is an alias for New (uses the
%% same register), it is neither in the stack nor register descriptor
%% lists and we would crash when we didn't find it unless we remove
%% it from the database.
bsm_forget_var(GC#k_guard_clause{guard=G,body=B}, Old);
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_guard_match{body=Ms0}=Match, Old, New, InProt) ->
Ms = bsm_rename_ctx(Ms0, Old, New, InProt),
Match#k_guard_match{body=Ms};
bsm_rename_ctx(#k_test{}=Test, _, _, _) -> Test;
bsm_rename_ctx(#k_bif{}=Bif, _, _, _) -> Bif;
bsm_rename_ctx(#k_put{}=Put, _, _, _) -> Put;
bsm_rename_ctx(#k_call{}=Call, _, _, _) -> Call;
bsm_rename_ctx(#cg_block{}=Block, Old, _, false) ->
%% This block is not inside a protected. The match context variable cannot
%% possibly be live inside the block.
bsm_forget_var(Block, Old);
bsm_rename_ctx(#cg_block{es=Es0}=Block, Old, New, true) ->
%% A block in a protected. We must recursively rename the variable
%% 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{}=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)|
bsm_rename_ctx_list(Cs, Old, New, InProt)];
bsm_rename_ctx_list([], _, _, _) -> [].
bsm_rename_var(Old, Old, New) -> New;
bsm_rename_var(V, _, _) -> V.
%% bsm_forget_var(#l{}, Variable) -> #l{}
%% Remove a variable from the variable life-time database.
bsm_forget_var(Ke, V) ->
#l{vdb=Vdb} = L0 = get_kanno(Ke),
L = L0#l{vdb=keydelete(V, 1, Vdb)},
set_kanno(Ke, L).
%% block_cg([Kexpr], Le, Vdb, StackReg, St) -> {[Ainstr],StackReg,St}.
%% block_cg([Kexpr], Le, StackReg, St) -> {[Ainstr],StackReg,St}.
block_cg(Es, Le, _Vdb, Bef, St) ->
block_cg(Es, Le, Bef, St).
block_cg(Es, Le, Bef, #cg{is_top_block=false}=St) ->
cg_block(Es, Le#l.vdb, Bef, St);
block_cg(Es, Le, Bef, #cg{is_top_block=true}=St0) ->
%% No stack frame has been established yet. Do we need one?
case need_stackframe(Es) of
true ->
%% We need a stack frame. Generate the code and add the
%% code for creating and deallocating the stack frame.
{Is0,Aft,St} = cg_block(Es, Le#l.vdb, Bef,
St0#cg{is_top_block=false,need_frame=false}),
Is = top_level_block(Is0, Aft, max_reg(Bef#sr.reg), St),
{Is,Aft,St#cg{is_top_block=true}};
false ->
%% This sequence of instructions ending in a #k_match{} (a
%% 'case' or 'if') in the Erlang code does not need a
%% stack frame yet. Delay the creation (if a stack frame
%% is needed at all, it will be created inside the
%% #k_match{}).
cg_list(Es, Le#l.vdb, Bef, St0)
end.
%% need_stackframe([Kexpr]) -> true|false.
%% Does this list of instructions need a stack frame?
%%
%% A sequence of instructions that don't clobber the X registers
%% followed by a single #k_match{} doesn't need a stack frame.
need_stackframe([H|T]) ->
case H of
#k_bif{op=#k_internal{}} -> true;
#k_put{arg=#k_binary{}} -> true;
#k_bif{} -> need_stackframe(T);
#k_put{} -> need_stackframe(T);
#k_guard_match{} -> need_stackframe(T);
#k_match{} when T =:= [] -> false;
_ -> true
end;
need_stackframe([]) -> false.
cg_block([], _Vdb, Bef, St0) ->
{[],Bef,St0};
cg_block(Kes0, Vdb, Bef, St0) ->
{Kes2,Int1,St1} =
case basic_block(Kes0) of
{Kes1,LastI,Args,Rest} ->
cg_basic_block(Kes1, LastI, Args, Vdb, Bef, St0);
{Kes1,Rest} ->
cg_list(Kes1, Vdb, Bef, St0)
end,
{Kes3,Int2,St2} = cg_block(Rest, Vdb, Int1, St1),
{Kes2 ++ Kes3,Int2,St2}.
basic_block(Kes) -> basic_block(Kes, []).
basic_block([Ke|Kes], Acc) ->
case collect_block(Ke) of
include -> basic_block(Kes, [Ke|Acc]);
{block_end,As} ->
case Acc of
[] ->
%% If the basic block does not contain any #k_put{} instructions,
%% it serves no useful purpose to do basic block optimizations.
{[Ke],Kes};
_ ->
#l{i=I} = get_kanno(Ke),
{reverse(Acc, [Ke]),I,As,Kes}
end;
no_block -> {reverse(Acc, [Ke]),Kes}
end.
collect_block(#k_put{arg=Arg}) ->
%% #k_put{} instructions that may garbage collect are not allowed
%% in basic blocks.
case Arg of
#k_binary{} -> no_block;
#k_map{} -> no_block;
_ -> include
end;
collect_block(#k_call{op=Func,args=As}) ->
{block_end,As++func_vars(Func)};
collect_block(#k_enter{op=Func,args=As}) ->
{block_end,As++func_vars(Func)};
collect_block(#k_return{args=Rs}) ->
{block_end,Rs};
collect_block(#k_break{args=Bs}) ->
{block_end,Bs};
collect_block(_) -> no_block.
func_vars(#k_var{}=Var) ->
[Var];
func_vars(#k_remote{mod=M,name=F})
when is_record(M, k_var); is_record(F, k_var) ->
[M,F];
func_vars(_) -> [].
%% cg_basic_block([Kexpr], FirstI, LastI, Arguments, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
%%
%% Do a specialized code generation for a basic block of #put{}
%% instructions (that don't do any garbage collection) followed by a
%% call, break, or return.
%%
%% 'Arguments' is a list of the variables that must be loaded into
%% consecutive X registers before the last instruction in the block.
%% The point of this specialized code generation is to try put the
%% all of the variables in 'Arguments' into the correct X register
%% to begin with, instead of putting them into the first available
%% X register and having to move them to the correct X register
%% later.
%%
%% To achieve that, we attempt to reserve the X registers that the
%% variables in 'Arguments' will need to be in when the block ends.
%%
%% To make it more likely that reservations will be successful, we
%% will try to save variables that need to be saved to the stack as
%% early as possible (if an X register needed by a variable in
%% Arguments is occupied by another variable, the value in the
%% X register can be evicted if it is saved on the stack).
%%
%% We will take care not to increase the size of stack frame compared
%% to what the standard code generator would have done (that is, to
%% save all X registers at the last possible moment). We will do that
%% by extending the stack frame to the minimal size needed to save
%% all that needs to be saved using extend_stack/4, and use
%% save_carefully/4 during code generation to only save the variables
%% that can be saved without growing the stack frame.
cg_basic_block(Kes, Lf, As, Vdb, Bef, St0) ->
Int0 = reserve_arg_regs(As, Bef),
Int = extend_stack(Int0, Lf, Lf+1, Vdb),
{Keis,{Aft,St1}} =
flatmapfoldl(fun(Ke, St) -> cg_basic_block(Ke, St, Lf, Vdb) end,
{Int,St0}, need_heap(Kes)),
{Keis,Aft,St1}.
cg_basic_block(#cg_need_heap{}=Ke, {Bef,St0}, _Lf, Vdb) ->
{Keis,Aft,St1} = cg(Ke, Vdb, Bef, St0),
{Keis,{Aft,St1}};
cg_basic_block(Ke, {Bef,St0}, Lf, Vdb) ->
#l{i=I} = get_kanno(Ke),
%% Save all we can to increase the possibility that reserving
%% registers will succeed.
{Sis,Int0} = save_carefully(Bef, I, Lf+1, Vdb),
Int1 = reserve(Int0),
{Keis,Aft,St1} = cg(Ke, Vdb, Int1, St0),
{Sis ++ Keis,{Aft,St1}}.
%% reserve_arg_regs([Argument], Bef) -> Aft.
%% Try to reserve the X registers for all arguments. All registers
%% that we wish to reserve will be saved in Bef#sr.res.
reserve_arg_regs(As, Bef) ->
Res = reserve_arg_regs_1(As, 0),
reserve(Bef#sr{res=Res}).
reserve_arg_regs_1([#k_var{name=V}|As], I) ->
[{I,V}|reserve_arg_regs_1(As, I+1)];
reserve_arg_regs_1([A|As], I) ->
[{I,A}|reserve_arg_regs_1(As, I+1)];
reserve_arg_regs_1([], _) -> [].
%% reserve(Bef) -> Aft.
%% Try to reserve more registers. The registers we wish to reserve
%% are found in Bef#sr.res.
reserve(#sr{reg=Regs,stk=Stk,res=Res}=Sr) ->
Sr#sr{reg=reserve_1(Res, Regs, Stk)}.
reserve_1([{I,V}|Rs], [free|Regs], Stk) ->
[{reserved,I,V}|reserve_1(Rs, Regs, Stk)];
reserve_1([{I,V}|Rs], [{I,V}|Regs], Stk) ->
[{I,V}|reserve_1(Rs, Regs, Stk)];
reserve_1([{I,V}|Rs], [{I,Var}|Regs], Stk) ->
case on_stack(Var, Stk) of
true -> [{reserved,I,V}|reserve_1(Rs, Regs, Stk)];
false -> [{I,Var}|reserve_1(Rs, Regs, Stk)]
end;
reserve_1([{I,V}|Rs], [{reserved,I,_}|Regs], Stk) ->
[{reserved,I,V}|reserve_1(Rs, Regs, Stk)];
reserve_1([{I,V}|Rs], [], Stk) ->
[{reserved,I,V}|reserve_1(Rs, [], Stk)];
reserve_1([], Regs, _) -> Regs.
%% extend_stack(Bef, FirstBefore, LastFrom, Vdb) -> Aft.
%% Extend the stack enough to fit all variables alive past LastFrom
%% and not already on the stack.
extend_stack(#sr{stk=Stk0}=Bef, Fb, Lf, Vdb) ->
Stk1 = clear_dead_stk(Stk0, Fb, Vdb),
New = new_not_on_stack(Stk1, Fb, Lf, Vdb),
Stk2 = foldl(fun ({V,_,_}, Stk) -> put_stack(V, Stk) end, Stk1, New),
Stk = Stk0 ++ lists:duplicate(length(Stk2) - length(Stk0), free),
Bef#sr{stk=Stk}.
%% save_carefully(Bef, FirstBefore, LastFrom, Vdb) -> {[SaveVar],Aft}.
%% Save variables which are used past current point and which are not
%% already on the stack, but only if the variables can be saved without
%% growing the stack frame.
save_carefully(#sr{stk=Stk}=Bef, Fb, Lf, Vdb) ->
New0 = new_not_on_stack(Stk, Fb, Lf, Vdb),
New = keysort(2, New0),
save_carefully_1(New, Bef, []).
save_carefully_1([{V,_,_}|Vs], #sr{reg=Regs,stk=Stk0}=Bef, Acc) ->
case put_stack_carefully(V, Stk0) of
error ->
{reverse(Acc),Bef};
Stk1 ->
SrcReg = fetch_reg(V, Regs),
Move = {move,SrcReg,fetch_stack(V, Stk1)},
{x,_} = SrcReg, %Assertion - must be X register.
save_carefully_1(Vs, Bef#sr{stk=Stk1}, [Move|Acc])
end;
save_carefully_1([], Bef, Acc) ->
{reverse(Acc),Bef}.
%% top_level_block([Instruction], Bef, MaxRegs, St) -> [Instruction].
%% For the top-level block, allocate a stack frame a necessary,
%% adjust Y register numbering and instructions that return
%% from the function.
top_level_block(Keis, #sr{stk=[]}, _MaxRegs, #cg{need_frame=false}) ->
Keis;
top_level_block(Keis, Bef, MaxRegs, _St) ->
%% This top block needs an allocate instruction before it, and a
%% deallocate instruction before each return.
FrameSz = length(Bef#sr.stk),
MaxY = FrameSz-1,
Keis1 = flatmap(fun ({call_only,Arity,Func}) ->
[{call_last,Arity,Func,FrameSz}];
({call_ext_only,Arity,Func}) ->
[{call_ext_last,Arity,Func,FrameSz}];
({apply_only,Arity}) ->
[{apply_last,Arity,FrameSz}];
(return) ->
[{deallocate,FrameSz},return];
(Tuple) when is_tuple(Tuple) ->
[turn_yregs(Tuple, MaxY)];
(Other) ->
[Other]
end, Keis),
[{allocate_zero,FrameSz,MaxRegs}|Keis1].
%% turn_yregs(Size, Tuple, MaxY) -> Tuple'
%% Renumber y register so that {y,0} becomes {y,FrameSize-1},
%% {y,FrameSize-1} becomes {y,0} and so on. This is to make nested
%% catches work. The code generation algorithm gives a lower register
%% number to the outer catch, which is wrong.
turn_yregs({call,_,_}=I, _MaxY) -> I;
turn_yregs({call_ext,_,_}=I, _MaxY) -> I;
turn_yregs({jump,_}=I, _MaxY) -> I;
turn_yregs({label,_}=I, _MaxY) -> I;
turn_yregs({line,_}=I, _MaxY) -> I;
turn_yregs({test_heap,_,_}=I, _MaxY) -> I;
turn_yregs({bif,Op,F,A,B}, MaxY) ->
{bif,Op,F,turn_yreg(A, MaxY),turn_yreg(B, MaxY)};
turn_yregs({gc_bif,Op,F,Live,A,B}, MaxY) when is_integer(Live) ->
{gc_bif,Op,F,Live,turn_yreg(A, MaxY),turn_yreg(B, MaxY)};
turn_yregs({get_tuple_element,S,N,D}, MaxY) ->
{get_tuple_element,turn_yreg(S, MaxY),N,turn_yreg(D, MaxY)};
turn_yregs({put_tuple,Arity,D}, MaxY) ->
{put_tuple,Arity,turn_yreg(D, MaxY)};
turn_yregs({select_val,R,F,L}, MaxY) ->
{select_val,turn_yreg(R, MaxY),F,L};
turn_yregs({test,Op,F,L}, MaxY) ->
{test,Op,F,turn_yreg(L, MaxY)};
turn_yregs({test,Op,F,Live,A,B}, MaxY) when is_integer(Live) ->
{test,Op,F,Live,turn_yreg(A, MaxY),turn_yreg(B, MaxY)};
turn_yregs({Op,A}, MaxY) ->
{Op,turn_yreg(A, MaxY)};
turn_yregs({Op,A,B}, MaxY) ->
{Op,turn_yreg(A, MaxY),turn_yreg(B, MaxY)};
turn_yregs({Op,A,B,C}, MaxY) ->
{Op,turn_yreg(A, MaxY),turn_yreg(B, MaxY),turn_yreg(C, MaxY)};
turn_yregs(Tuple, MaxY) ->
turn_yregs(tuple_size(Tuple), Tuple, MaxY).
turn_yregs(1, Tp, _) ->
Tp;
turn_yregs(N, Tp, MaxY) ->
E = turn_yreg(element(N, Tp), MaxY),
turn_yregs(N-1, setelement(N, Tp, E), MaxY).
turn_yreg({yy,YY}, MaxY) ->
{y,MaxY-YY};
turn_yreg({list,Ls},MaxY) ->
{list,turn_yreg(Ls, MaxY)};
turn_yreg([_|_]=Ts, MaxY) ->
[turn_yreg(T, MaxY) || T <- Ts];
turn_yreg(Other, _MaxY) ->
Other.
%% select_cg(Sclause, V, TypeFail, ValueFail, StackReg, State) ->
%% {Is,StackReg,State}.
%% Selecting type and value needs two failure labels, TypeFail is the
%% label to jump to of the next type test when this type fails, and
%% ValueFail is the label when this type is correct but the value is
%% wrong. These are different as in the second case there is no need
%% to try the next type, it will always fail.
select_cg(#k_type_clause{type=Type,values=Vs}, Var, Tf, Vf, Bef, St) ->
#k_var{name=V} = Var,
select_cg(Type, Vs, V, Tf, Vf, Bef, St).
select_cg(k_cons, [S], V, Tf, Vf, Bef, St) ->
select_cons(S, V, Tf, Vf, Bef, St);
select_cg(k_nil, [S], V, Tf, Vf, Bef, St) ->
select_nil(S, V, Tf, Vf, Bef, St);
select_cg(k_binary, [S], V, Tf, Vf, Bef, St) ->
select_binary(S, V, Tf, Vf, Bef, St);
select_cg(k_bin_seg, S, V, Tf, _Vf, Bef, St) ->
select_bin_segs(S, V, Tf, Bef, St);
select_cg(k_bin_int, S, V, Tf, _Vf, Bef, St) ->
select_bin_segs(S, V, Tf, Bef, St);
select_cg(k_bin_end, [S], V, Tf, _Vf, Bef, St) ->
select_bin_end(S, V, Tf, Bef, St);
select_cg(k_map, S, V, Tf, Vf, Bef, St) ->
select_map(S, V, Tf, Vf, Bef, St);
select_cg(k_literal, S, V, Tf, Vf, Bef, St) ->
select_literal(S, V, Tf, Vf, Bef, St);
select_cg(Type, Scs, V, Tf, Vf, Bef, St0) ->
{Vis,{Aft,St1}} =
mapfoldl(fun (S, {Int,Sta}) ->
{Val,Is,Inta,Stb} = select_val(S, V, Vf, Bef, Sta),
{{Is,[Val]},{sr_merge(Int, Inta),Stb}}
end, {void,St0}, Scs),
OptVls = combine(lists:sort(combine(Vis))),
{Vls,Sis,St2} = select_labels(OptVls, St1, [], []),
{select_val_cg(Type, fetch_var(V, Bef), Vls, Tf, Vf, Sis), Aft, St2}.
select_val_cg(k_tuple, R, [Arity,{f,Lbl}], Tf, Vf, [{label,Lbl}|Sis]) ->
[{test,is_tuple,{f,Tf},[R]},{test,test_arity,{f,Vf},[R,Arity]}|Sis];
select_val_cg(k_tuple, R, Vls, Tf, Vf, Sis) ->
[{test,is_tuple,{f,Tf},[R]},{select_tuple_arity,R,{f,Vf},{list,Vls}}|Sis];
select_val_cg(Type, R, [Val, {f,Lbl}], Fail, Fail, [{label,Lbl}|Sis]) ->
[{test,is_eq_exact,{f,Fail},[R,{type(Type),Val}]}|Sis];
select_val_cg(Type, R, [Val, {f,Lbl}], Tf, Vf, [{label,Lbl}|Sis]) ->
[{test,select_type_test(Type),{f,Tf},[R]},
{test,is_eq_exact,{f,Vf},[R,{type(Type),Val}]}|Sis];
select_val_cg(Type, R, Vls0, Tf, Vf, Sis) ->
Vls1 = [case Value of
{f,_Lbl} -> Value;
_ -> {type(Type),Value}
end || Value <- Vls0],
[{test,select_type_test(Type),{f,Tf},[R]}, {select_val,R,{f,Vf},{list,Vls1}}|Sis].
type(k_atom) -> atom;
type(k_float) -> float;
type(k_int) -> integer.
select_type_test(k_int) -> is_integer;
select_type_test(k_atom) -> is_atom;
select_type_test(k_float) -> is_float.
combine([{Is,Vs1}, {Is,Vs2}|Vis]) -> combine([{Is,Vs1 ++ Vs2}|Vis]);
combine([V|Vis]) -> [V|combine(Vis)];
combine([]) -> [].
select_labels([{Is,Vs}|Vis], St0, Vls, Sis) ->
{Lbl,St1} = new_label(St0),
select_labels(Vis, St1, add_vls(Vs, Lbl, Vls), [[{label,Lbl}|Is]|Sis]);
select_labels([], St, Vls, Sis) ->
{Vls,append(Sis),St}.
add_vls([V|Vs], Lbl, Acc) ->
add_vls(Vs, Lbl, [V, {f,Lbl}|Acc]);
add_vls([], _, Acc) -> Acc.
select_literal(S, V, Tf, Vf, Bef, St) ->
Reg = fetch_var(V, Bef),
F = fun(ValClause, Fail, St0) ->
{Val,Is,Aft,St1} = select_val(ValClause, V, Vf, Bef, St0),
Test = {test,is_eq_exact,{f,Fail},[Reg,{literal,Val}]},
{[Test|Is],Aft,St1}
end,
match_fmf(F, Tf, St, S).
select_cons(#k_val_clause{val=#k_cons{hd=Hd,tl=Tl},body=B,anno=#l{i=I,vdb=Vdb}},
V, Tf, Vf, Bef, St0) ->
Es = [Hd,Tl],
{Eis,Int,St1} = select_extract_cons(V, Es, I, Vdb, Bef, St0),
{Bis,Aft,St2} = match_cg(B, Vf, Int, St1),
{[{test,is_nonempty_list,{f,Tf},[fetch_var(V, Bef)]}] ++ Eis ++ Bis,Aft,St2}.
select_nil(#k_val_clause{val=#k_nil{},body=B}, V, Tf, Vf, Bef, St0) ->
{Bis,Aft,St1} = match_cg(B, Vf, Bef, St0),
{[{test,is_nil,{f,Tf},[fetch_var(V, Bef)]}] ++ Bis,Aft,St1}.
select_binary(#k_val_clause{val=#k_binary{segs=#k_var{name=V}},body=B,
anno=#l{i=I,vdb=Vdb}}, V, Tf, Vf, Bef, St0) ->
#cg{ctx=OldCtx} = St0,
Int0 = clear_dead(Bef#sr{reg=Bef#sr.reg}, I, Vdb),
{Bis0,Aft,St1} = match_cg(B, Vf, Int0, St0#cg{ctx=V}),
CtxReg = fetch_var(V, Int0),
Live = max_reg(Bef#sr.reg),
Bis1 = [{test,bs_start_match2,{f,Tf},Live,[CtxReg,{context,V}],CtxReg},
{bs_save2,CtxReg,{V,V}}|Bis0],
Bis = finish_select_binary(Bis1),
{Bis,Aft,St1#cg{ctx=OldCtx}};
select_binary(#k_val_clause{val=#k_binary{segs=#k_var{name=Ivar}},body=B,
anno=#l{i=I,vdb=Vdb}}, V, Tf, Vf, Bef, St0) ->
#cg{ctx=OldCtx} = St0,
Regs = put_reg(Ivar, Bef#sr.reg),
Int0 = clear_dead(Bef#sr{reg=Regs}, I, Vdb),
{Bis0,Aft,St1} = match_cg(B, Vf, Int0, St0#cg{ctx=Ivar}),
CtxReg = fetch_var(Ivar, Int0),
Live = max_reg(Bef#sr.reg),
Bis1 = [{test,bs_start_match2,{f,Tf},Live,
[fetch_var(V, Bef),{context,Ivar}],CtxReg},
{bs_save2,CtxReg,{Ivar,Ivar}}|Bis0],
Bis = finish_select_binary(Bis1),
{Bis,Aft,St1#cg{ctx=OldCtx}}.
finish_select_binary([{bs_save2,R,Point}=I,{bs_restore2,R,Point}|Is]) ->
[I|finish_select_binary(Is)];
finish_select_binary([{bs_save2,R,Point}=I,{test,is_eq_exact,_,_}=Test,
{bs_restore2,R,Point}|Is]) ->
[I,Test|finish_select_binary(Is)];
finish_select_binary([{test,bs_match_string,F,[Ctx,BinList]}|Is])
when is_list(BinList) ->
I = {test,bs_match_string,F,[Ctx,list_to_bitstring(BinList)]},
[I|finish_select_binary(Is)];
finish_select_binary([I|Is]) ->
[I|finish_select_binary(Is)];
finish_select_binary([]) -> [].
%% New instructions for selection of binary segments.
select_bin_segs(Scs, Ivar, Tf, Bef, St) ->
match_fmf(fun(S, Fail, Sta) ->
select_bin_seg(S, Ivar, Fail, Bef, Sta) end,
Tf, St, Scs).
select_bin_seg(#k_val_clause{val=#k_bin_seg{size=Size,unit=U,type=T,
seg=Seg,flags=Fs0,next=Next},
body=B,
anno=#l{i=I,vdb=Vdb,a=A}}, Ivar, Fail, Bef, St0) ->
Ctx = St0#cg.ctx,
Fs = [{anno,A}|Fs0],
Es = case Next of
[] -> [Seg];
_ -> [Seg,Next]
end,
{Mis,Int,St1} = select_extract_bin(Es, Size, U, T, Fs, Fail,
I, Vdb, Bef, Ctx, B, St0),
{Bis,Aft,St2} = match_cg(B, Fail, Int, St1),
CtxReg = fetch_var(Ctx, Bef),
Is = if
Mis =:= [] ->
%% No bs_restore2 instruction needed if no match instructions.
Bis;
true ->
[{bs_restore2,CtxReg,{Ctx,Ivar}}|Mis++Bis]
end,
{Is,Aft,St2};
select_bin_seg(#k_val_clause{val=#k_bin_int{size=Sz,unit=U,flags=Fs,
val=Val,next=Next},
body=B,
anno=#l{i=I,vdb=Vdb}}, Ivar, Fail, Bef, St0) ->
Ctx = St0#cg.ctx,
{Mis,Int,St1} = select_extract_int(Next, Val, Sz, U, Fs, Fail,
I, Vdb, Bef, Ctx, St0),
{Bis,Aft,St2} = match_cg(B, Fail, Int, St1),
CtxReg = fetch_var(Ctx, Bef),
Is = case Mis ++ Bis of
[{test,bs_match_string,F,[OtherCtx,Bin1]},
{bs_save2,OtherCtx,_},
{bs_restore2,OtherCtx,_},
{test,bs_match_string,F,[OtherCtx,Bin2]}|Is0] ->
%% We used to do this optimization later, but it
%% turns out that in huge functions with many
%% bs_match_string instructions, it's a big win
%% to do the combination now. To avoid copying the
%% binary data again and again, we'll combine bitstrings
%% in a list and convert all of it to a bitstring later.
[{test,bs_match_string,F,[OtherCtx,[Bin1,Bin2]]}|Is0];
Is0 ->
Is0
end,
{[{bs_restore2,CtxReg,{Ctx,Ivar}}|Is],Aft,St2}.
select_extract_int(#k_var{name=Tl}, Val, #k_int{val=Sz}, U, Fs, Vf,
I, Vdb, Bef, Ctx, St) ->
Bits = U*Sz,
Bin = case member(big, Fs) of
true ->
<<Val:Bits>>;
false ->
true = member(little, Fs), %Assertion.
<<Val:Bits/little>>
end,
Bits = bit_size(Bin), %Assertion.
CtxReg = fetch_var(Ctx, Bef),
Is = if
Bits =:= 0 ->
[{bs_save2,CtxReg,{Ctx,Tl}}];
true ->
[{test,bs_match_string,{f,Vf},[CtxReg,Bin]},
{bs_save2,CtxReg,{Ctx,Tl}}]
end,
{Is,clear_dead(Bef, I, Vdb),St}.
select_extract_bin([#k_var{name=Hd},#k_var{name=Tl}], Size0, Unit, Type, Flags, Vf,
I, Vdb, Bef, Ctx, _Body, St) ->
SizeReg = get_bin_size_reg(Size0, Bef),
{Es,Aft} =
case vdb_find(Hd, Vdb) of
{_,_,Lhd} when Lhd =< I ->
%% The extracted value will not be used.
CtxReg = fetch_var(Ctx, Bef),
Live = max_reg(Bef#sr.reg),
Skip = build_skip_instr(Type, Vf, CtxReg, Live,
SizeReg, Unit, Flags),
{[Skip,{bs_save2,CtxReg,{Ctx,Tl}}],Bef};
{_,_,_} ->
Reg = put_reg(Hd, Bef#sr.reg),
Int1 = Bef#sr{reg=Reg},
Rhd = fetch_reg(Hd, Reg),
CtxReg = fetch_reg(Ctx, Reg),
Live = max_reg(Bef#sr.reg),
{[build_bs_instr(Type, Vf, CtxReg, Live, SizeReg,
Unit, Flags, Rhd),
{bs_save2,CtxReg,{Ctx,Tl}}],Int1}
end,
{Es,clear_dead(Aft, I, Vdb),St};
select_extract_bin([#k_var{name=Hd}], Size, Unit, binary, Flags, Vf,
I, Vdb, Bef, Ctx, Body, St) ->
%% Match the last segment of a binary. We KNOW that the size
%% must be 'all'.
#k_atom{val=all} = Size, %Assertion.
{Es,Aft} =
case vdb_find(Hd, Vdb) of
{_,_,Lhd} when Lhd =< I ->
%% The result will not be used. Furthermore, since we
%% we are at the end of the binary, the position will
%% not be used again; thus, it is safe to do a cheaper
%% test of the unit.
CtxReg = fetch_var(Ctx, Bef),
{case Unit of
1 ->
[];
_ ->
[{test,bs_test_unit,{f,Vf},[CtxReg,Unit]}]
end,Bef};
{_,_,_} ->
case is_context_unused(Body) of
false ->
Reg = put_reg(Hd, Bef#sr.reg),
Int1 = Bef#sr{reg=Reg},
Rhd = fetch_reg(Hd, Reg),
CtxReg = fetch_reg(Ctx, Reg),
Name = bs_get_binary2,
Live = max_reg(Bef#sr.reg),
{[{test,Name,{f,Vf},Live,
[CtxReg,atomic(Size),Unit,{field_flags,Flags}],Rhd}],
Int1};
true ->
%% Since the matching context will not be used again,
%% we can reuse its register. Reusing the register
%% opens some interesting optimizations in the
%% run-time system.
Reg0 = Bef#sr.reg,
CtxReg = fetch_reg(Ctx, Reg0),
Reg = replace_reg_contents(Ctx, Hd, Reg0),
Int1 = Bef#sr{reg=Reg},
Name = bs_get_binary2,
Live = max_reg(Int1#sr.reg),
{[{test,Name,{f,Vf},Live,
[CtxReg,atomic(Size),Unit,{field_flags,Flags}],CtxReg}],
Int1}
end
end,
{Es,clear_dead(Aft, I, Vdb),St}.
%% is_context_unused(Ke) -> true | false
%% Simple heurististic to determine whether the code that follows
%% will use the current matching context again. (The liveness
%% information is too conservative to be useful for this purpose.)
%% 'true' means that the code that follows will definitely not use
%% the context again (because it is a block, not guard or matching
%% code); 'false' that we are not sure (there could be more
%% matching).
is_context_unused(#k_alt{then=Then}) ->
%% #k_alt{} can be used for different purposes. If the Then part
%% is a block, it means that matching has finished and is used for a guard
%% to choose between the matched clauses.
is_context_unused(Then);
is_context_unused(#cg_block{}) ->
true;
is_context_unused(_) ->
false.
select_bin_end(#k_val_clause{val=#k_bin_end{},body=B}, Ivar, Tf, Bef, St0) ->
Ctx = St0#cg.ctx,
{Bis,Aft,St2} = match_cg(B, Tf, Bef, St0),
CtxReg = fetch_var(Ctx, Bef),
{[{bs_restore2,CtxReg,{Ctx,Ivar}},
{test,bs_test_tail2,{f,Tf},[CtxReg,0]}|Bis],Aft,St2}.
get_bin_size_reg(#k_var{name=V}, Bef) ->
fetch_var(V, Bef);
get_bin_size_reg(Literal, _Bef) ->
atomic(Literal).
build_bs_instr(Type, Vf, CtxReg, Live, SizeReg, Unit, Flags, Rhd) ->
{Format,Name} = case Type of
integer -> {plain,bs_get_integer2};
float -> {plain,bs_get_float2};
binary -> {plain,bs_get_binary2};
utf8 -> {utf,bs_get_utf8};
utf16 -> {utf,bs_get_utf16};
utf32 -> {utf,bs_get_utf32}
end,
case Format of
plain ->
{test,Name,{f,Vf},Live,
[CtxReg,SizeReg,Unit,{field_flags,Flags}],Rhd};
utf ->
{test,Name,{f,Vf},Live,
[CtxReg,{field_flags,Flags}],Rhd}
end.
build_skip_instr(Type, Vf, CtxReg, Live, SizeReg, Unit, Flags) ->
{Format,Name} = case Type of
utf8 -> {utf,bs_skip_utf8};
utf16 -> {utf,bs_skip_utf16};
utf32 -> {utf,bs_skip_utf32};
_ -> {plain,bs_skip_bits2}
end,
case Format of
plain ->
{test,Name,{f,Vf},[CtxReg,SizeReg,Unit,{field_flags,Flags}]};
utf ->
{test,Name,{f,Vf},[CtxReg,Live,{field_flags,Flags}]}
end.
select_val(#k_val_clause{val=#k_tuple{es=Es},body=B,anno=#l{i=I,vdb=Vdb}},
V, Vf, Bef, St0) ->
{Eis,Int,St1} = select_extract_tuple(V, Es, I, Vdb, Bef, St0),
{Bis,Aft,St2} = match_cg(B, Vf, Int, St1),
{length(Es),Eis ++ Bis,Aft,St2};
select_val(#k_val_clause{val=Val0,body=B}, _V, Vf, Bef, St0) ->
Val = case Val0 of
#k_atom{val=Lit} -> Lit;
#k_float{val=Lit} -> Lit;
#k_int{val=Lit} -> Lit;
#k_literal{val=Lit} -> Lit
end,
{Bis,Aft,St1} = match_cg(B, Vf, Bef, St0),
{Val,Bis,Aft,St1}.
%% select_extract_tuple(Src, [V], I, Vdb, StackReg, State) ->
%% {[E],StackReg,State}.
%% Extract tuple elements, but only if they do not immediately die.
select_extract_tuple(Src, Vs, I, Vdb, Bef, St) ->
F = fun (#k_var{name=V}, {Int0,Elem}) ->
case vdb_find(V, Vdb) of
{V,_,L} when L =< I -> {[], {Int0,Elem+1}};
_Other ->
Reg1 = put_reg(V, Int0#sr.reg),
Int1 = Int0#sr{reg=Reg1},
Rsrc = fetch_var(Src, Int1),
{[{get_tuple_element,Rsrc,Elem,fetch_reg(V, Reg1)}],
{Int1,Elem+1}}
end
end,
{Es,{Aft,_}} = flatmapfoldl(F, {Bef,0}, Vs),
{Es,Aft,St}.
select_map(Scs, V, Tf, Vf, Bef, St0) ->
Reg = fetch_var(V, Bef),
{Is,Aft,St1} =
match_fmf(fun(#k_val_clause{val=#k_map{op=exact,es=Es},
body=B,anno=#l{i=I,vdb=Vdb}}, Fail, St1) ->
select_map_val(V, Es, B, Fail, I, Vdb, Bef, St1)
end, Vf, St0, Scs),
{[{test,is_map,{f,Tf},[Reg]}|Is],Aft,St1}.
select_map_val(V, Es, B, Fail, I, Vdb, Bef, St0) ->
{Eis,Int,St1} = select_extract_map(V, Es, Fail, I, Vdb, Bef, St0),
{Bis,Aft,St2} = match_cg(B, Fail, Int, St1),
{Eis++Bis,Aft,St2}.
select_extract_map(_, [], _, _, _, Bef, St) -> {[],Bef,St};
select_extract_map(Src, Vs, Fail, I, Vdb, Bef, St) ->
%% First split the instruction flow
%% We want one set of each
%% 1) has_map_fields (no target registers)
%% 2) get_map_elements (with target registers)
%% Assume keys are term-sorted
Rsrc = fetch_var(Src, Bef),
{{HasKs,GetVs,HasVarKs,GetVarVs},Aft} =
foldr(fun(#k_map_pair{key=#k_var{name=K},val=#k_var{name=V}},
{{HasKsi,GetVsi,HasVarVsi,GetVarVsi},Int0}) ->
case vdb_find(V, Vdb) of
{V,_,L} when L =< I ->
RK = fetch_var(K,Int0),
{{HasKsi,GetVsi,[RK|HasVarVsi],GetVarVsi},Int0};
_Other ->
Reg1 = put_reg(V, Int0#sr.reg),
Int1 = Int0#sr{reg=Reg1},
RK = fetch_var(K,Int0),
RV = fetch_reg(V,Reg1),
{{HasKsi,GetVsi,HasVarVsi,[[RK,RV]|GetVarVsi]},Int1}
end;
(#k_map_pair{key=Key,val=#k_var{name=V}},
{{HasKsi,GetVsi,HasVarVsi,GetVarVsi},Int0}) ->
case vdb_find(V, Vdb) of
{V,_,L} when L =< I ->
{{[atomic(Key)|HasKsi],GetVsi,HasVarVsi,GetVarVsi},Int0};
_Other ->
Reg1 = put_reg(V, Int0#sr.reg),
Int1 = Int0#sr{reg=Reg1},
{{HasKsi,[atomic(Key),fetch_reg(V, Reg1)|GetVsi],
HasVarVsi,GetVarVsi},Int1}
end
end, {{[],[],[],[]},Bef}, Vs),
Code = [{test,has_map_fields,{f,Fail},Rsrc,{list,HasKs}} || HasKs =/= []] ++
[{test,has_map_fields,{f,Fail},Rsrc,{list,[K]}} || K <- HasVarKs] ++
[{get_map_elements, {f,Fail},Rsrc,{list,GetVs}} || GetVs =/= []] ++
[{get_map_elements, {f,Fail},Rsrc,{list,[K,V]}} || [K,V] <- GetVarVs],
{Code, Aft, St}.
select_extract_cons(Src, [#k_var{name=Hd},#k_var{name=Tl}], I, Vdb, Bef, St) ->
Rsrc = fetch_var(Src, Bef),
Int = clear_dead(Bef, I, Vdb),
{{_,_,Lhd},{_,_,Ltl}} = {vdb_find(Hd, Vdb),vdb_find(Tl, Vdb)},
case {Lhd =< I, Ltl =< I} of
{true,true} ->
%% Both dead.
{[],Bef,St};
{true,false} ->
%% Head dead.
Reg0 = put_reg(Tl, Bef#sr.reg),
Aft = Int#sr{reg=Reg0},
Rtl = fetch_reg(Tl, Reg0),
{[{get_tl,Rsrc,Rtl}],Aft,St};
{false,true} ->
%% Tail dead.
Reg0 = put_reg(Hd, Bef#sr.reg),
Aft = Int#sr{reg=Reg0},
Rhd = fetch_reg(Hd, Reg0),
{[{get_hd,Rsrc,Rhd}],Aft,St};
{false,false} ->
%% Both used.
Reg0 = put_reg(Tl, put_reg(Hd, Bef#sr.reg)),
Aft = Bef#sr{reg=Reg0},
Rhd = fetch_reg(Hd, Reg0),
Rtl = fetch_reg(Tl, Reg0),
{[{get_hd,Rsrc,Rhd},{get_tl,Rsrc,Rtl}],Aft,St}
end.
guard_clause_cg(#k_guard_clause{anno=#l{vdb=Vdb},guard=G,body=B}, Fail, Bef, St0) ->
{Gis,Int,St1} = guard_cg(G, Fail, Vdb, Bef, St0),
{Bis,Aft,St} = match_cg(B, Fail, Int, St1),
{Gis ++ Bis,Aft,St}.
%% guard_cg(Guard, Fail, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
%% A guard is a boolean expression of tests. Tests return true or
%% false. A fault in a test causes the test to return false. Tests
%% never return the boolean, instead we generate jump code to go to
%% the correct exit point. Primops and tests all go to the next
%% instruction on success or jump to a failure label.
guard_cg(#k_protected{arg=Ts,ret=Rs,anno=#l{vdb=Pdb}}, Fail, _Vdb, Bef, St) ->
protected_cg(Ts, Rs, Fail, Pdb, 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,
case Inverted of
false ->
test_cg(Test, As, Fail, I, Vdb, Bef, St0);
true ->
{Psucc,St1} = new_label(St0),
{Is,Aft,St2} = test_cg(Test, As, Psucc, I, Vdb, Bef, St1),
{Is++[{jump,{f,Fail}},{label,Psucc}],Aft,St2}
end;
guard_cg(G, _Fail, Vdb, Bef, St) ->
%%ok = io:fwrite("cg ~w: ~p~n", [?LINE,{G,Fail,Vdb,Bef}]),
{Gis,Aft,St1} = cg(G, 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, 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)),
{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
%% the next instruction and failure jumps to Fail. If there are
%% return values then these must be set to 'false' on failure,
%% control always passes to the next instruction.
protected_cg(Ts, [], Fail, Vdb, Bef, St0) ->
%% Protect these calls, revert when done.
{Tis,Aft,St1} = guard_cg_list(Ts, Fail, Vdb, Bef, St0#cg{bfail=Fail}),
{Tis,Aft,St1#cg{bfail=St0#cg.bfail}};
protected_cg(Ts, Rs, _Fail, Vdb, Bef, St0) ->
{Pfail,St1} = new_label(St0),
{Psucc,St2} = new_label(St1),
{Tis,Aft,St3} = guard_cg_list(Ts, Pfail, Vdb, Bef,
St2#cg{bfail=Pfail}),
%%ok = io:fwrite("cg ~w: ~p~n", [?LINE,{Rs,I,Vdb,Aft}]),
%% Set return values to false.
Mis = [{move,{atom,false},fetch_var(V,Aft)}||#k_var{name=V} <- Rs],
{Tis ++ [{jump,{f,Psucc}},
{label,Pfail}] ++ Mis ++ [{label,Psucc}],
Aft,St3#cg{bfail=St0#cg.bfail}}.
%% test_cg(TestName, Args, Fail, I, Vdb, Bef, St) -> {[Ainstr],Aft,St}.
%% Generate test instruction. Use explicit fail label here.
test_cg(is_map, [A], Fail, I, Vdb, Bef, St) ->
%% We must avoid creating code like this:
%%
%% move x(0) y(0)
%% is_map Fail [x(0)]
%% make_fun => x(0) %% Overwrite x(0)
%% put_map_assoc y(0) ...
%%
%% The code is safe, but beam_validator does not understand that.
%% Extending beam_validator to handle such (rare) code as the
%% above would make it slower for all programs. Instead, change
%% the code generator to always prefer the Y register for is_map()
%% and put_map_assoc() instructions, ensuring that they use the
%% same register.
Arg = cg_reg_arg_prefer_y(A, Bef),
Aft = clear_dead(Bef, I, Vdb),
{[{test,is_map,{f,Fail},[Arg]}],Aft,St};
test_cg(is_boolean, [#k_atom{val=Val}], Fail, I, Vdb, Bef, St) ->
Aft = clear_dead(Bef, I, Vdb),
Is = case is_boolean(Val) of
true -> [];
false -> [{jump,{f,Fail}}]
end,
{Is,Aft,St};
test_cg(Test, As, Fail, I, Vdb, Bef, St) ->
Args = cg_reg_args(As, Bef),
Aft = clear_dead(Bef, I, Vdb),
{[beam_utils:bif_to_test(Test, Args, {f,Fail})],Aft,St}.
%% 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
%% an externally generated failure label, LastFail. N.B. We do not
%% know or care how the failure labels are used.
match_fmf(F, LastFail, St, [H]) ->
F(H, LastFail, St);
match_fmf(F, LastFail, St0, [H|T]) ->
{Fail,St1} = new_label(St0),
{R,Aft1,St2} = F(H, Fail, St1),
{Rs,Aft2,St3} = match_fmf(F, LastFail, St2, T),
{R ++ [{label,Fail}] ++ Rs,sr_merge(Aft1, Aft2),St3}.
%% call_cg(Func, [Arg], [Ret], Le, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
%% enter_cg(Func, [Arg], Le, Vdb, Bef, St) -> {[Ainstr],Aft,St}.
%% Call and enter first put the arguments into registers and save any
%% other registers, then clean up and compress the stack and set the
%% frame size. Finally the actual call is made. Call then needs the
%% return values filled in.
call_cg(#k_var{}=Var, As, Rs, Le, Vdb, Bef, St0) ->
{Sis,Int} = cg_setup_call(As++[Var], Bef, Le#l.i, Vdb),
%% Put return values in registers.
Reg = load_vars(Rs, clear_regs(Int#sr.reg)),
%% Build complete code and final stack/register state.
Arity = length(As),
{Frees,Aft} = free_dead(clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb)),
{Sis ++ Frees ++ [line(Le),{call_fun,Arity}],Aft,
need_stack_frame(St0)};
call_cg(#k_remote{mod=Mod,name=Name}, As, Rs, Le, Vdb, Bef, St0)
when is_record(Mod, k_var); is_record(Name, k_var) ->
{Sis,Int} = cg_setup_call(As++[Mod,Name], Bef, Le#l.i, Vdb),
%% Put return values in registers.
Reg = load_vars(Rs, clear_regs(Int#sr.reg)),
%% Build complete code and final stack/register state.
Arity = length(As),
St = need_stack_frame(St0),
%%{Call,St1} = build_call(Func, Arity, St0),
{Frees,Aft} = free_dead(clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb)),
{Sis ++ Frees ++ [line(Le),{apply,Arity}],Aft,St};
call_cg(Func, As, Rs, Le, Vdb, Bef, St0) ->
case St0 of
#cg{bfail=Fail} when Fail =/= 0 ->
%% Inside a guard. The only allowed function call is to
%% erlang:error/1,2. We will generate the following code:
%%
%% move {atom,ok} DestReg
%% jump FailureLabel
#k_remote{mod=#k_atom{val=erlang},
name=#k_atom{val=error}} = Func, %Assertion.
[#k_var{name=DestVar}] = Rs,
Int0 = clear_dead(Bef, Le#l.i, Vdb),
Reg = put_reg(DestVar, Int0#sr.reg),
Int = Int0#sr{reg=Reg},
Dst = fetch_reg(DestVar, Reg),
{[{move,{atom,ok},Dst},{jump,{f,Fail}}],
clear_dead(Int, Le#l.i, Vdb),St0};
#cg{} ->
%% Ordinary function call in a function body.
{Sis,Int} = cg_setup_call(As, Bef, Le#l.i, Vdb),
%% Put return values in registers.
Reg = load_vars(Rs, clear_regs(Int#sr.reg)),
%% Build complete code and final stack/register state.
Arity = length(As),
{Call,St1} = build_call(Func, Arity, St0),
{Frees,Aft} = free_dead(clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb)),
{Sis ++ Frees ++ [line(Le)|Call],Aft,St1}
end.
build_call(#k_remote{mod=#k_atom{val=erlang},name=#k_atom{val='!'}}, 2, St0) ->
{[send],need_stack_frame(St0)};
build_call(#k_remote{mod=#k_atom{val=Mod},name=#k_atom{val=Name}}, Arity, St0) ->
{[{call_ext,Arity,{extfunc,Mod,Name,Arity}}],need_stack_frame(St0)};
build_call(#k_local{name=Name}, Arity, St0) when is_atom(Name) ->
{Lbl,St1} = local_func_label(Name, Arity, need_stack_frame(St0)),
{[{call,Arity,{f,Lbl}}],St1}.
free_dead(#sr{stk=Stk0}=Aft) ->
{Instr,Stk} = free_dead(Stk0, 0, [], []),
{Instr,Aft#sr{stk=Stk}}.
free_dead([dead|Stk], Y, Instr, StkAcc) ->
%% Note: kill/1 is equivalent to init/1 (translated by beam_asm).
%% We use kill/1 to help further optimisation passes.
free_dead(Stk, Y+1, [{kill,{yy,Y}}|Instr], [free|StkAcc]);
free_dead([Any|Stk], Y, Instr, StkAcc) ->
free_dead(Stk, Y+1, Instr, [Any|StkAcc]);
free_dead([], _, Instr, StkAcc) -> {Instr,reverse(StkAcc)}.
enter_cg(#k_var{} = Var, As, Le, Vdb, Bef, St0) ->
{Sis,Int} = cg_setup_call(As++[Var], Bef, Le#l.i, Vdb),
%% Build complete code and final stack/register state.
Arity = length(As),
{Sis ++ [line(Le),{call_fun,Arity},return],
clear_dead(Int#sr{reg=clear_regs(Int#sr.reg)}, Le#l.i, Vdb),
need_stack_frame(St0)};
enter_cg(#k_remote{mod=Mod,name=Name}, As, Le, Vdb, Bef, St0)
when is_record(Mod, k_var); is_record(Name, k_var) ->
{Sis,Int} = cg_setup_call(As++[Mod,Name], Bef, Le#l.i, Vdb),
%% Build complete code and final stack/register state.
Arity = length(As),
St = need_stack_frame(St0),
{Sis ++ [line(Le),{apply_only,Arity}],
clear_dead(Int#sr{reg=clear_regs(Int#sr.reg)}, Le#l.i, Vdb),
St};
enter_cg(Func, As, Le, Vdb, Bef, St0) ->
{Sis,Int} = cg_setup_call(As, Bef, Le#l.i, Vdb),
%% Build complete code and final stack/register state.
Arity = length(As),
{Call,St1} = build_enter(Func, Arity, St0),
Line = enter_line(Func, Arity, Le),
{Sis ++ Line ++ Call,
clear_dead(Int#sr{reg=clear_regs(Int#sr.reg)}, Le#l.i, Vdb),
St1}.
build_enter(#k_remote{mod=#k_atom{val=erlang},name=#k_atom{val='!'}}, 2, St0) ->
{[send,return],need_stack_frame(St0)};
build_enter(#k_remote{mod=#k_atom{val=Mod},name=#k_atom{val=Name}}, Arity, St0) ->
St1 = case trap_bif(Mod, Name, Arity) of
true -> need_stack_frame(St0);
false -> St0
end,
{[{call_ext_only,Arity,{extfunc,Mod,Name,Arity}}],St1};
build_enter(#k_local{name=Name}, Arity, St0) when is_atom(Name) ->
{Lbl,St1} = local_func_label(Name, Arity, St0),
{[{call_only,Arity,{f,Lbl}}],St1}.
enter_line(#k_remote{mod=#k_atom{val=Mod},name=#k_atom{val=Name}}, Arity, Le) ->
case erl_bifs:is_safe(Mod, Name, Arity) of
false ->
%% Tail-recursive call, possibly to a BIF.
%% We'll need a line instruction in case the
%% BIF call fails.
[line(Le)];
true ->
%% Call to a safe BIF. Since it cannot fail,
%% we don't need any line instruction here.
[]
end;
enter_line(_, _, _) ->
%% Tail-recursive call to a local function. A line
%% instruction will not be useful.
[].
%% local_func_label(Name, Arity, State) -> {Label,State'}
%% local_func_label({Name,Arity}, State) -> {Label,State'}
%% Get the function entry label for a local function.
local_func_label(Name, Arity, St) ->
local_func_label({Name,Arity}, St).
local_func_label(Key, #cg{functable=Map}=St0) ->
case Map of
#{Key := Label} -> {Label,St0};
_ ->
{Label,St} = new_label(St0),
{Label,St#cg{functable=Map#{Key => Label}}}
end.
%% need_stack_frame(State) -> State'
%% Make a note in the state that this function will need a stack frame.
need_stack_frame(#cg{need_frame=true}=St) -> St;
need_stack_frame(St) -> St#cg{need_frame=true}.
%% trap_bif(Mod, Name, Arity) -> true|false
%% Trap bifs that need a stack frame.
trap_bif(erlang, link, 1) -> true;
trap_bif(erlang, unlink, 1) -> true;
trap_bif(erlang, monitor_node, 2) -> true;
trap_bif(erlang, group_leader, 2) -> true;
trap_bif(erlang, exit, 2) -> true;
trap_bif(_, _, _) -> false.
%% bif_cg(#k_bif{}, Le, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
%% Generate code a BIF.
bif_cg(#k_bif{op=#k_internal{name=Name},args=As,ret=Rs}, Le, Vdb, Bef, St) ->
internal_cg(Name, As, Rs, Le, Vdb, Bef, St);
bif_cg(#k_bif{op=#k_remote{mod=#k_atom{val=erlang},name=#k_atom{val=Name}},
args=As,ret=Rs}, Le, Vdb, Bef, St) ->
Ar = length(As),
case is_gc_bif(Name, Ar) of
false ->
bif_cg(Name, As, Rs, Le, Vdb, Bef, St);
true ->
gc_bif_cg(Name, As, Rs, Le, Vdb, Bef, St)
end.
%% internal_cg(Bif, [Arg], [Ret], Le, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
internal_cg(bs_context_to_binary=Instr, [Src0], [], Le, Vdb, Bef, St0) ->
[Src] = cg_reg_args([Src0], Bef),
{[{Instr,Src}],clear_dead(Bef, Le#l.i, Vdb), St0};
internal_cg(dsetelement, [Index0,Tuple0,New0], _Rs, Le, Vdb, Bef, St0) ->
[New,Tuple,{integer,Index1}] = cg_reg_args([New0,Tuple0,Index0], Bef),
Index = Index1-1,
{[{set_tuple_element,New,Tuple,Index}],
clear_dead(Bef, Le#l.i, Vdb), St0};
internal_cg(make_fun, [Func0,Arity0|As], Rs, Le, Vdb, Bef, St0) ->
%% This behaves more like a function call.
#k_atom{val=Func} = Func0,
#k_int{val=Arity} = Arity0,
{Sis,Int} = cg_setup_call(As, Bef, Le#l.i, Vdb),
Reg = load_vars(Rs, clear_regs(Int#sr.reg)),
{FuncLbl,St1} = local_func_label(Func, Arity, St0),
MakeFun = {make_fun2,{f,FuncLbl},0,0,length(As)},
{Sis ++ [MakeFun],
clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb),
St1};
internal_cg(bs_init_writable=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(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);
internal_cg(guard_error, [ExitCall], _Rs, Le, Vdb, Bef, St) ->
%% A call an exit BIF from inside a #k_guard_match{}.
%% Generate a standard call, but leave the register descriptors
%% alone, effectively pretending that there was no call.
#k_call{op=#k_remote{mod=#k_atom{val=Mod},name=#k_atom{val=Name}},
args=As} = ExitCall,
Arity = length(As),
{Ms,_} = cg_call_args(As, Bef, Le#l.i, Vdb),
Call = {call_ext,Arity,{extfunc,Mod,Name,Arity}},
Is = Ms++[line(Le),Call],
{Is,Bef,St};
internal_cg(raw_raise=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}.
%% bif_cg(Bif, [Arg], [Ret], Le, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
bif_cg(Bif, As, [#k_var{name=V}], Le, Vdb, Bef, St0) ->
Ars = cg_reg_args(As, Bef),
%% If we are inside a catch and in a body (not in guard) and the
%% BIF may fail, we must save everything that will be alive after
%% the catch (because the code after the code assumes that all
%% variables that are live are stored on the stack).
%%
%% Currently, we are somewhat pessimistic in
%% that we save any variable that will be live after this BIF call.
MayFail = not erl_bifs:is_safe(erlang, Bif, length(As)),
{Sis,Int0} =
case MayFail of
true ->
maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St0);
false ->
{[],Bef}
end,
Int1 = clear_dead(Int0, Le#l.i, Vdb),
Reg = put_reg(V, Int1#sr.reg),
Int = Int1#sr{reg=Reg},
Dst = fetch_reg(V, Reg),
BifFail = {f,St0#cg.bfail},
%% We need a line instructions for BIFs that may fail in a body.
Line = case BifFail of
{f,0} when MayFail ->
[line(Le)];
_ ->
[]
end,
{Sis++Line++[{bif,Bif,BifFail,Ars,Dst}],
clear_dead(Int, Le#l.i, Vdb), St0}.
%% gc_bif_cg(Bif, [Arg], [Ret], Le, Vdb, StackReg, State) ->
%% {[Ainstr],StackReg,State}.
gc_bif_cg(Bif, As, [#k_var{name=V}], Le, Vdb, Bef, St0) ->
Ars = cg_reg_args(As, Bef),
%% If we are inside a catch and in a body (not in guard) and the
%% BIF may fail, we must save everything that will be alive after
%% the catch (because the code after the code assumes that all
%% variables that are live are stored on the stack).
%%
%% Currently, we are somewhat pessimistic in
%% that we save any variable that will be live after this BIF call.
{Sis,Int0} = maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St0),
Int1 = clear_dead(Int0, Le#l.i, Vdb),
Reg = put_reg(V, Int1#sr.reg),
Int = Int1#sr{reg=Reg},
Dst = fetch_reg(V, Reg),
BifFail = {f,St0#cg.bfail},
Line = case BifFail of
{f,0} -> [line(Le)];
{f,_} -> []
end,
{Sis++Line++[{gc_bif,Bif,BifFail,max_reg(Bef#sr.reg),Ars,Dst}],
clear_dead(Int, Le#l.i, Vdb), St0}.
%% recv_loop_cg(TimeOut, ReceiveVar, ReceiveMatch, TimeOutExprs,
%% [Ret], Le, Vdb, Bef, St) -> {[Ainstr],Aft,St}.
recv_loop_cg(Te, Rvar, Rm, Tes, Rs, Le, Vdb, Bef, St0) ->
{Sis,Int0} = adjust_stack(Bef, Le#l.i, Le#l.i, Vdb),
Int1 = Int0#sr{reg=clear_regs(Int0#sr.reg)},
%% Get labels.
{Rl,St1} = new_label(St0),
{Tl,St2} = new_label(St1),
{Bl,St3} = new_label(St2),
St4 = St3#cg{break=Bl,recv=Rl}, %Set correct receive labels
{Ris,Raft,St5} = cg_recv_mesg(Rvar, Rm, Tl, Int1, St4),
{Wis,Taft,St6} = cg_recv_wait(Te, Tes, Le#l.i, Int1, St5),
Int2 = sr_merge(Raft, Taft), %Merge stack/registers
Reg = load_vars(Rs, Int2#sr.reg),
{Sis ++ [line(Le)] ++ Ris ++ [{label,Tl}] ++ Wis ++ [{label,Bl}],
clear_dead(Int2#sr{reg=Reg}, Le#l.i, Vdb),
St6#cg{break=St0#cg.break,recv=St0#cg.recv}}.
%% cg_recv_mesg( ) -> {[Ainstr],Aft,St}.
cg_recv_mesg(#k_var{name=R}, Rm, Tl, Bef, St0) ->
Int0 = Bef#sr{reg=put_reg(R, Bef#sr.reg)},
Ret = fetch_reg(R, Int0#sr.reg),
%% Int1 = clear_dead(Int0, I, Rm#l.vdb),
Int1 = Int0,
{Mis,Int2,St1} = match_cg(Rm, none, Int1, St0),
{[{label,St1#cg.recv},{loop_rec,{f,Tl},Ret}|Mis],Int2,St1}.
%% cg_recv_wait(Te, Tes, I, Vdb, Int2, St3) -> {[Ainstr],Aft,St}.
cg_recv_wait(#k_atom{val=infinity}, #cg_block{anno=Le,es=Tes}, I, Bef, St0) ->
%% We know that the 'after' body will never be executed.
%% But to keep the stack and register information up to date,
%% we will generate the code for the 'after' body, and then discard it.
Int1 = clear_dead(Bef, I, Le#l.vdb),
{_,Int2,St1} = cg_block(Tes, Le#l.vdb,
Int1#sr{reg=clear_regs(Int1#sr.reg)}, St0),
{[{wait,{f,St1#cg.recv}}],Int2,St1};
cg_recv_wait(#k_int{val=0}, #cg_block{anno=Le,es=Tes}, _I, Bef, St0) ->
{Tis,Int,St1} = cg_block(Tes, Le#l.vdb, Bef, St0),
{[timeout|Tis],Int,St1};
cg_recv_wait(Te, #cg_block{anno=Le,es=Tes}, I, Bef, St0) ->
Reg = cg_reg_arg(Te, Bef),
%% Must have empty registers here! Bug if anything in registers.
Int0 = clear_dead(Bef, I, Le#l.vdb),
{Tis,Int,St1} = cg_block(Tes, Le#l.vdb,
Int0#sr{reg=clear_regs(Int0#sr.reg)}, St0),
{[{wait_timeout,{f,St1#cg.recv},Reg},timeout] ++ Tis,Int,St1}.
%% recv_next_cg(Le, Vdb, StackReg, St) -> {[Ainstr],StackReg,St}.
%% Use adjust stack to clear stack, but only need it for Aft.
recv_next_cg(Le, Vdb, Bef, St) ->
{Sis,Aft} = adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb),
{[{loop_rec_end,{f,St#cg.recv}}] ++ Sis,Aft,St}. %Joke
%% try_cg(TryBlock, [BodyVar], TryBody, [ExcpVar], TryHandler, [Ret],
%% Le, Vdb, StackReg, St) -> {[Ainstr],StackReg,St}.
try_cg(Ta, Vs, Tb, Evs, Th, Rs, Le, Vdb, Bef, St0) ->
{B,St1} = new_label(St0), %Body label
{H,St2} = new_label(St1), %Handler label
{E,St3} = new_label(St2), %End label
#l{i=TryTag} = get_kanno(Ta),
Int1 = Bef#sr{stk=put_catch(TryTag, Bef#sr.stk)},
TryReg = fetch_stack({catch_tag,TryTag}, Int1#sr.stk),
{Ais,Int2,St4} = cg(Ta, Vdb, Int1, St3#cg{break=B,in_catch=true}),
Int3 = Int2#sr{stk=drop_catch(TryTag, Int2#sr.stk)},
St5 = St4#cg{break=E,in_catch=St3#cg.in_catch},
{Bis,Baft,St6} = cg(Tb, Vdb, Int3#sr{reg=load_vars(Vs, Int3#sr.reg)}, St5),
{His,Haft,St7} = cg(Th, Vdb, Int3#sr{reg=load_vars(Evs, Int3#sr.reg)}, St6),
Int4 = sr_merge(Baft, Haft), %Merge stack/registers
Aft = Int4#sr{reg=load_vars(Rs, Int4#sr.reg)},
{[{'try',TryReg,{f,H}}] ++ Ais ++
[{label,B},{try_end,TryReg}] ++ Bis ++
[{label,H},{try_case,TryReg}] ++ His ++
[{label,E}],
clear_dead(Aft, Le#l.i, Vdb),
St7#cg{break=St0#cg.break}}.
try_enter_cg(Ta, Vs, Tb, Evs, Th, Le, Vdb, Bef, St0) ->
{B,St1} = new_label(St0), %Body label
{H,St2} = new_label(St1), %Handler label
#l{i=TryTag} = get_kanno(Ta),
Int1 = Bef#sr{stk=put_catch(TryTag, Bef#sr.stk)},
TryReg = fetch_stack({catch_tag,TryTag}, Int1#sr.stk),
{Ais,Int2,St3} = cg(Ta, Vdb, Int1, St2#cg{break=B,in_catch=true}),
Int3 = Int2#sr{stk=drop_catch(TryTag, Int2#sr.stk)},
St4 = St3#cg{in_catch=St2#cg.in_catch},
{Bis,Baft,St5} = cg(Tb, Vdb, Int3#sr{reg=load_vars(Vs, Int3#sr.reg)}, St4),
{His,Haft,St6} = cg(Th, Vdb, Int3#sr{reg=load_vars(Evs, Int3#sr.reg)}, St5),
Int4 = sr_merge(Baft, Haft), %Merge stack/registers
Aft = Int4,
{[{'try',TryReg,{f,H}}] ++ Ais ++
[{label,B},{try_end,TryReg}] ++ Bis ++
[{label,H},{try_case,TryReg}] ++ His,
clear_dead(Aft, Le#l.i, Vdb),
St6#cg{break=St0#cg.break}}.
%% catch_cg(CatchBlock, Ret, Le, Vdb, Bef, St) -> {[Ainstr],Aft,St}.
catch_cg(#cg_block{es=C}, #k_var{name=R}, Le, Vdb, Bef, St0) ->
{B,St1} = new_label(St0),
CatchTag = Le#l.i,
Int1 = Bef#sr{stk=put_catch(CatchTag, Bef#sr.stk)},
CatchReg = fetch_stack({catch_tag,CatchTag}, Int1#sr.stk),
{Cis,Int2,St2} = cg_block(C, Le#l.vdb, Int1,
St1#cg{break=B,in_catch=true}),
[] = Int2#sr.reg, %Assertion.
Aft = Int2#sr{reg=[{0,R}],stk=drop_catch(CatchTag, Int2#sr.stk)},
{[{'catch',CatchReg,{f,B}}] ++ Cis ++
[{label,B},{catch_end,CatchReg}],
clear_dead(Aft, Le#l.i, Vdb),
St2#cg{break=St1#cg.break,in_catch=St1#cg.in_catch}}.
%% put_cg([Var], Constr, Le, Vdb, Bef, St) -> {[Ainstr],Aft,St}.
%% We have to be careful how a 'put' works. First the structure is
%% built, then it is filled and finally things can be cleared. The
%% annotation must reflect this and make sure that the return
%% variable is allocated first.
%%
%% put_list and put_map are atomic instructions, both of
%% which can safely resuse one of the source registers as target.
put_cg([#k_var{name=R}], #k_cons{hd=Hd,tl=Tl}, Le, Vdb, Bef, St) ->
[S1,S2] = cg_reg_args([Hd,Tl], Bef),
Int0 = clear_dead(Bef, Le#l.i, Vdb),
Int1 = Int0#sr{reg=put_reg(R, Int0#sr.reg)},
Ret = fetch_reg(R, Int1#sr.reg),
{[{put_list,S1,S2,Ret}], Int1, St};
put_cg([#k_var{name=R}], #k_binary{segs=Segs}, Le, Vdb, Bef,
#cg{bfail=Bfail}=St) ->
%% At run-time, binaries are constructed in three stages:
%% 1) First the size of the binary is calculated.
%% 2) Then the binary is allocated.
%% 3) Then each field in the binary is constructed.
%% For simplicity, we use the target register to also hold the
%% size of the binary. Therefore the target register must *not*
%% be one of the source registers.
%% First allocate the target register.
Int0 = Bef#sr{reg=put_reg(R, Bef#sr.reg)},
Target = fetch_reg(R, Int0#sr.reg),
%% Also allocate a scratch register for size calculations.
Temp = find_scratch_reg(Int0#sr.reg),
%% First generate the code that constructs each field.
Fail = {f,Bfail},
PutCode = cg_bin_put(Segs, Fail, Bef),
{Sis,Int1} = maybe_adjust_stack(Int0, Le#l.i, Le#l.i+1, Vdb, St),
MaxRegs = max_reg(Bef#sr.reg),
Aft = clear_dead(Int1, Le#l.i, Vdb),
%% Now generate the complete code for constructing the binary.
Code = cg_binary(PutCode, Target, Temp, Fail, MaxRegs, Le#l.a),
{Sis++Code,Aft,St};
%% Map: single variable key.
put_cg([#k_var{name=R}], #k_map{op=Op,var=Map,
es=[#k_map_pair{key=#k_var{}=K,val=V}]},
Le, Vdb, Bef, St0) ->
{Sis,Int0} = maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St0),
SrcReg = cg_reg_arg_prefer_y(Map, Int0),
Line = line(Le#l.a),
List = [cg_reg_arg(K,Int0),cg_reg_arg(V,Int0)],
Live = max_reg(Bef#sr.reg),
%% The target register can reuse one of the source registers.
Aft0 = clear_dead(Int0, Le#l.i, Vdb),
Aft = Aft0#sr{reg=put_reg(R, Aft0#sr.reg)},
Target = fetch_reg(R, Aft#sr.reg),
{Is,St1} = put_cg_map(Line, Op, SrcReg, Target, Live, List, St0),
{Sis++Is,Aft,St1};
%% Map: (possibly) multiple literal keys.
put_cg([#k_var{name=R}], #k_map{op=Op,var=Map,es=Es}, Le, Vdb, Bef, St0) ->
%% assert key literals
[] = [Var || #k_map_pair{key=#k_var{}=Var} <- Es],
{Sis,Int0} = maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St0),
SrcReg = cg_reg_arg_prefer_y(Map, Int0),
Line = line(Le#l.a),
%% fetch registers for values to be put into the map
List = flatmap(fun(#k_map_pair{key=K,val=V}) ->
[atomic(K),cg_reg_arg(V, Int0)]
end, Es),
Live = max_reg(Bef#sr.reg),
%% The target register can reuse one of the source registers.
Aft0 = clear_dead(Int0, Le#l.i, Vdb),
Aft = Aft0#sr{reg=put_reg(R, Aft0#sr.reg)},
Target = fetch_reg(R, Aft#sr.reg),
{Is,St1} = put_cg_map(Line, Op, SrcReg, Target, Live, List, St0),
{Sis++Is,Aft,St1};
%% Everything else.
put_cg([#k_var{name=R}], Con, Le, Vdb, Bef, St) ->
%% Find a place for the return register first.
Int = Bef#sr{reg=put_reg(R, Bef#sr.reg)},
Ret = fetch_reg(R, Int#sr.reg),
Ais = case Con of
#k_tuple{es=Es} ->
[{put_tuple,length(Es),Ret}] ++ cg_build_args(Es, Bef);
Other ->
[{move,cg_reg_arg(Other, Int),Ret}]
end,
{Ais,clear_dead(Int, Le#l.i, Vdb),St}.
put_cg_map(Line, Op0, SrcReg, Target, Live, List, St0) ->
Bfail = St0#cg.bfail,
Fail = {f,St0#cg.bfail},
Op = case Op0 of
assoc -> put_map_assoc;
exact -> put_map_exact
end,
{OkLbl,St1} = new_label(St0),
{BadLbl,St2} = new_label(St1),
Is = if
Bfail =:= 0 orelse Op =:= put_map_assoc ->
[Line,{Op,{f,0},SrcReg,Target,Live,{list,List}}];
true ->
%% Ensure that Target is always set, even if
%% the map update operation fails. That is necessary
%% because Target may be included in a test_heap
%% instruction.
[Line,
{Op,{f,BadLbl},SrcReg,Target,Live,{list,List}},
{jump,{f,OkLbl}},
{label,BadLbl},
{move,{atom,ok},Target},
{jump,Fail},
{label,OkLbl}]
end,
{Is,St2}.
%%%
%%% Code generation for constructing binaries.
%%%
cg_binary([{bs_put_binary,Fail,{atom,all},U,_Flags,Src}|PutCode],
Target, Temp, Fail, MaxRegs, Anno) ->
Line = line(Anno),
Live = cg_live(Target, MaxRegs),
SzCode = cg_bitstr_size(PutCode, Target, Temp, Fail, Live),
BinFlags = {field_flags,[]},
Code = [Line|SzCode] ++
[case member(single_use, Anno) of
true ->
{bs_private_append,Fail,Target,U,Src,BinFlags,Target};
false ->
{bs_append,Fail,Target,0,MaxRegs,U,Src,BinFlags,Target}
end] ++ PutCode,
cg_bin_opt(Code);
cg_binary(PutCode, Target, Temp, Fail, MaxRegs, Anno) ->
Line = line(Anno),
Live = cg_live(Target, MaxRegs),
{InitOp,SzCode} = cg_binary_size(PutCode, Target, Temp, Fail, Live),
Code = [Line|SzCode] ++ [{InitOp,Fail,Target,0,MaxRegs,
{field_flags,[]},Target}|PutCode],
cg_bin_opt(Code).
cg_live({x,X}, MaxRegs) when X =:= MaxRegs -> MaxRegs+1;
cg_live({x,X}, MaxRegs) when X < MaxRegs -> MaxRegs.
%% Generate code that calculate the size of the bitstr to be
%% built in BITS.
cg_bitstr_size(PutCode, Target, Temp, Fail, Live) ->
{Bits,Es} = cg_bitstr_size_1(PutCode, 0, []),
reverse(cg_gen_binsize(Es, Target, Temp, Fail, Live,
[{move,{integer,Bits},Target}])).
cg_bitstr_size_1([{bs_put_utf8,_,_,Src}|Next], Bits, Acc) ->
cg_bitstr_size_1(Next, Bits, [{'*',{bs_utf8_size,Src},8}|Acc]);
cg_bitstr_size_1([{bs_put_utf16,_,_,Src}|Next], Bits, Acc) ->
cg_bitstr_size_1(Next, Bits, [{'*',{bs_utf16_size,Src},8}|Acc]);
cg_bitstr_size_1([{bs_put_utf32,_,_,_}|Next], Bits, Acc) ->
cg_bitstr_size_1(Next, Bits+32, Acc);
cg_bitstr_size_1([{_,_,S,U,_,Src}|Next], Bits, Acc) ->
case S of
{integer,N} -> cg_bitstr_size_1(Next, Bits+N*U, Acc);
{atom,all} -> cg_bitstr_size_1(Next, Bits, [{bit_size,Src}|Acc]);
_ when U =:= 1 -> cg_bitstr_size_1(Next, Bits, [S|Acc]);
_ -> cg_bitstr_size_1(Next, Bits, [{'*',S,U}|Acc])
end;
cg_bitstr_size_1([], Bits, Acc) -> {Bits,Acc}.
%% Generate code that calculate the size of the bitstr to be
%% built in BYTES or BITS (depending on what is easiest).
cg_binary_size(PutCode, Target, Temp, Fail, Live) ->
{InitInstruction,Szs} = cg_binary_size_1(PutCode, 0, []),
SizeExpr = reverse(cg_gen_binsize(Szs, Target, Temp, Fail, Live, [{move,{integer,0},Target}])),
{InitInstruction,SizeExpr}.
cg_binary_size_1([{bs_put_utf8,_Fail,_Flags,Src}|T], Bits, Acc) ->
cg_binary_size_1(T, Bits, [{8,{bs_utf8_size,Src}}|Acc]);
cg_binary_size_1([{bs_put_utf16,_Fail,_Flags,Src}|T], Bits, Acc) ->
cg_binary_size_1(T, Bits, [{8,{bs_utf16_size,Src}}|Acc]);
cg_binary_size_1([{bs_put_utf32,_Fail,_Flags,_Src}|T], Bits, Acc) ->
cg_binary_size_1(T, Bits+32, Acc);
cg_binary_size_1([{_Put,_Fail,S,U,_Flags,Src}|T], Bits, Acc) ->
cg_binary_size_2(S, U, Src, T, Bits, Acc);
cg_binary_size_1([], Bits, Acc) ->
Bytes = Bits div 8,
RemBits = Bits rem 8,
Sizes0 = sort([{1,{integer,RemBits}},{8,{integer,Bytes}}|Acc]),
Sizes = filter(fun({_,{integer,0}}) -> false;
(_) -> true end, Sizes0),
case Sizes of
[{1,_}|_] ->
{bs_init_bits,cg_binary_bytes_to_bits(Sizes, [])};
[{8,_}|_] ->
{bs_init2,[E || {8,E} <- Sizes]};
[] ->
{bs_init_bits,[]}
end.
cg_binary_size_2({integer,N}, U, _, Next, Bits, Acc) ->
cg_binary_size_1(Next, Bits+N*U, Acc);
cg_binary_size_2({atom,all}, U, E, Next, Bits, Acc) ->
if
U rem 8 =:= 0 ->
cg_binary_size_1(Next, Bits, [{8,{byte_size,E}}|Acc]);
true ->
cg_binary_size_1(Next, Bits, [{1,{bit_size,E}}|Acc])
end;
cg_binary_size_2(Reg, 1, _, Next, Bits, Acc) ->
cg_binary_size_1(Next, Bits, [{1,Reg}|Acc]);
cg_binary_size_2(Reg, 8, _, Next, Bits, Acc) ->
cg_binary_size_1(Next, Bits, [{8,Reg}|Acc]);
cg_binary_size_2(Reg, U, _, Next, Bits, Acc) ->
cg_binary_size_1(Next, Bits, [{1,{'*',Reg,U}}|Acc]).
cg_binary_bytes_to_bits([{8,{integer,N}}|T], Acc) ->
cg_binary_bytes_to_bits(T, [{integer,8*N}|Acc]);
cg_binary_bytes_to_bits([{8,{byte_size,Reg}}|T], Acc) ->
cg_binary_bytes_to_bits(T, [{bit_size,Reg}|Acc]);
cg_binary_bytes_to_bits([{8,Reg}|T], Acc) ->
cg_binary_bytes_to_bits(T, [{'*',Reg,8}|Acc]);
cg_binary_bytes_to_bits([{1,Sz}|T], Acc) ->
cg_binary_bytes_to_bits(T, [Sz|Acc]);
cg_binary_bytes_to_bits([], Acc) ->
cg_binary_bytes_to_bits_1(sort(Acc)).
cg_binary_bytes_to_bits_1([{integer,I},{integer,J}|T]) ->
cg_binary_bytes_to_bits_1([{integer,I+J}|T]);
cg_binary_bytes_to_bits_1([H|T]) ->
[H|cg_binary_bytes_to_bits_1(T)];
cg_binary_bytes_to_bits_1([]) -> [].
cg_gen_binsize([{'*',{bs_utf8_size,Src},B}|T], Target, Temp, Fail, Live, Acc) ->
Size = {bs_utf8_size,Fail,Src,Temp},
Add = {bs_add,Fail,[Target,Temp,B],Target},
cg_gen_binsize(T, Target, Temp, Fail, Live,
[Add,Size|Acc]);
cg_gen_binsize([{'*',{bs_utf16_size,Src},B}|T], Target, Temp, Fail, Live, Acc) ->
Size = {bs_utf16_size,Fail,Src,Temp},
Add = {bs_add,Fail,[Target,Temp,B],Target},
cg_gen_binsize(T, Target, Temp, Fail, Live,
[Add,Size|Acc]);
cg_gen_binsize([{'*',A,B}|T], Target, Temp, Fail, Live, Acc) ->
cg_gen_binsize(T, Target, Temp, Fail, Live,
[{bs_add,Fail,[Target,A,B],Target}|Acc]);
cg_gen_binsize([{bit_size,B}|T], Target, Temp, Fail, Live, Acc) ->
cg_gen_binsize([Temp|T], Target, Temp, Fail, Live,
[{gc_bif,bit_size,Fail,Live,[B],Temp}|Acc]);
cg_gen_binsize([{byte_size,B}|T], Target, Temp, Fail, Live, Acc) ->
cg_gen_binsize([Temp|T], Target, Temp, Fail, Live,
[{gc_bif,byte_size,Fail,Live,[B],Temp}|Acc]);
cg_gen_binsize([{bs_utf8_size,B}|T], Target, Temp, Fail, Live, Acc) ->
cg_gen_binsize([Temp|T], Target, Temp, Fail, Live,
[{bs_utf8_size,Fail,B,Temp}|Acc]);
cg_gen_binsize([{bs_utf16_size,B}|T], Target, Temp, Fail, Live, Acc) ->
cg_gen_binsize([Temp|T], Target, Temp, Fail, Live,
[{bs_utf16_size,Fail,B,Temp}|Acc]);
cg_gen_binsize([E0|T], Target, Temp, Fail, Live, Acc) ->
cg_gen_binsize(T, Target, Temp, Fail, Live,
[{bs_add,Fail,[Target,E0,1],Target}|Acc]);
cg_gen_binsize([], _, _, _, _, Acc) -> Acc.
%% cg_bin_opt(Code0) -> Code
%% Optimize the size calculations for binary construction.
cg_bin_opt([{move,S1,{x,X}=D},{gc_bif,Op,Fail,Live0,As,Dst}|Is]) ->
Live = if
X + 1 =:= Live0 -> X;
true -> Live0
end,
[{gc_bif,Op,Fail,Live,As,D}|cg_bin_opt([{move,S1,Dst}|Is])];
cg_bin_opt([{move,_,_}=I1,{Op,_,_,_}=I2|Is])
when Op =:= bs_utf8_size orelse Op =:= bs_utf16_size ->
[I2|cg_bin_opt([I1|Is])];
cg_bin_opt([{bs_add,_,[{integer,0},Src,1],Dst}|Is]) ->
cg_bin_opt_1([{move,Src,Dst}|Is]);
cg_bin_opt([{bs_add,_,[Src,{integer,0},_],Dst}|Is]) ->
cg_bin_opt_1([{move,Src,Dst}|Is]);
cg_bin_opt(Is) ->
cg_bin_opt_1(Is).
cg_bin_opt_1([{move,Size,D},{bs_append,Fail,D,Extra,Regs,U,Bin,Flags,D}|Is]) ->
[{bs_append,Fail,Size,Extra,Regs,U,Bin,Flags,D}|cg_bin_opt(Is)];
cg_bin_opt_1([{move,Size,D},{bs_private_append,Fail,D,U,Bin,Flags,D}|Is]) ->
[{bs_private_append,Fail,Size,U,Bin,Flags,D}|cg_bin_opt(Is)];
cg_bin_opt_1([{move,Size,D},{Op,Fail,D,Extra,Regs,Flags,D}|Is])
when Op =:= bs_init2; Op =:= bs_init_bits ->
Bytes = case Size of
{integer,Int} -> Int;
_ -> Size
end,
[{Op,Fail,Bytes,Extra,Regs,Flags,D}|cg_bin_opt(Is)];
cg_bin_opt_1([{move,S1,D},{bs_add,Fail,[D,S2,U],Dst}|Is]) ->
cg_bin_opt([{bs_add,Fail,[S1,S2,U],Dst}|Is]);
cg_bin_opt_1([{move,S1,D},{bs_add,Fail,[S2,D,U],Dst}|Is]) ->
cg_bin_opt([{bs_add,Fail,[S2,S1,U],Dst}|Is]);
cg_bin_opt_1([I|Is]) ->
[I|cg_bin_opt(Is)];
cg_bin_opt_1([]) ->
[].
cg_bin_put(#k_bin_seg{size=S0,unit=U,type=T,flags=Fs,seg=E0,next=Next},
Fail, Bef) ->
S1 = cg_reg_arg(S0, Bef),
E1 = cg_reg_arg(E0, Bef),
{Format,Op} = case T of
integer -> {plain,bs_put_integer};
utf8 -> {utf,bs_put_utf8};
utf16 -> {utf,bs_put_utf16};
utf32 -> {utf,bs_put_utf32};
binary -> {plain,bs_put_binary};
float -> {plain,bs_put_float}
end,
case Format of
plain ->
[{Op,Fail,S1,U,{field_flags,Fs},E1}|cg_bin_put(Next, Fail, Bef)];
utf ->
[{Op,Fail,{field_flags,Fs},E1}|cg_bin_put(Next, Fail, Bef)]
end;
cg_bin_put(#k_bin_end{}, _, _) -> [].
cg_build_args(As, Bef) ->
[{put,cg_reg_arg(A, Bef)} || A <- As].
%% return_cg([Val], Le, Vdb, Bef, St) -> {[Ainstr],Aft,St}.
%% break_cg([Val], Le, Vdb, Bef, St) -> {[Ainstr],Aft,St}.
%% These are very simple, just put return/break values in registers
%% from 0, then return/break. Use the call setup to clean up stack,
%% but must clear registers to ensure sr_merge works correctly.
return_cg(Rs, Le, Vdb, Bef, St) ->
{Ms,Int} = cg_setup_call(Rs, Bef, Le#l.i, Vdb),
{Ms ++ [return],Int#sr{reg=clear_regs(Int#sr.reg)},St}.
break_cg(Bs, Le, Vdb, Bef, St) ->
{Ms,Int} = cg_setup_call(Bs, Bef, Le#l.i, Vdb),
{Ms ++ [{jump,{f,St#cg.break}}],
Int#sr{reg=clear_regs(Int#sr.reg)},St}.
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(Reg0)),
{BreakVars,_} = mapfoldl(fun(_, RegNum) ->
{{RegNum,gbreakvar},RegNum+1}
end, length(Reg2), Bs),
Reg = Reg2 ++ BreakVars,
Aft = Int#sr{reg=Reg},
{Moves ++ [{jump,{f,St#cg.break}}],Aft,St}.
%% cg_reg_arg(Arg0, Info) -> Arg
%% cg_reg_args([Arg0], Info) -> [Arg]
%% Convert argument[s] into registers. Literal values are returned unchanged.
cg_reg_args(As, Bef) -> [cg_reg_arg(A, Bef) || A <- As].
cg_reg_arg(#k_var{name=V}, Bef) -> fetch_var(V, Bef);
cg_reg_arg(Literal, _) -> atomic(Literal).
cg_reg_arg_prefer_y(#k_var{name=V}, Bef) -> fetch_var_prefer_y(V, Bef);
cg_reg_arg_prefer_y(Literal, _) -> atomic(Literal).
%% cg_setup_call([Arg], Bef, Cur, Vdb) -> {[Instr],Aft}.
%% Do the complete setup for a call/enter.
cg_setup_call(As, Bef, I, Vdb) ->
{Ms,Int0} = cg_call_args(As, Bef, I, Vdb),
%% Have set up arguments, can now clean up, compress and save to stack.
Int1 = Int0#sr{stk=clear_dead_stk(Int0#sr.stk, I, Vdb),res=[]},
{Sis,Int2} = adjust_stack(Int1, I, I+1, Vdb),
{Ms ++ Sis,Int2}.
%% cg_call_args([Arg], SrState) -> {[Instr],SrState}.
%% Setup the arguments to a call/enter/bif. Put the arguments into
%% consecutive registers starting at {x,0} moving any data which
%% needs to be saved. Return a modified SrState structure with the
%% new register contents. N.B. the resultant register info will
%% contain non-variable values when there are non-variable values.
%%
%% This routine is complicated by unsaved values in x registers.
%% We'll move away any unsaved values that are in the registers
%% to be overwritten by the arguments.
cg_call_args(As, Bef, I, Vdb) ->
Regs0 = load_arg_regs(Bef#sr.reg, As),
Unsaved = unsaved_registers(Regs0, Bef#sr.stk, I, I+1, Vdb),
{UnsavedMoves,Regs} = move_unsaved(Unsaved, Bef#sr.reg, Regs0),
Moves0 = gen_moves(As, Bef),
Moves = order_moves(Moves0, find_scratch_reg(Regs)),
{UnsavedMoves ++ Moves,Bef#sr{reg=Regs}}.
%% load_arg_regs([Reg], Arguments) -> [Reg]
%% Update the register descriptor to include the arguments (from {x,0}
%% and upwards). Values in argument register are overwritten.
%% Values in x registers above the arguments are preserved.
load_arg_regs(Regs, As) -> load_arg_regs(Regs, As, 0).
load_arg_regs([_|Rs], [#k_var{name=V}|As], I) -> [{I,V}|load_arg_regs(Rs, As, I+1)];
load_arg_regs([_|Rs], [A|As], I) -> [{I,A}|load_arg_regs(Rs, As, I+1)];
load_arg_regs([], [#k_var{name=V}|As], I) -> [{I,V}|load_arg_regs([], As, I+1)];
load_arg_regs([], [A|As], I) -> [{I,A}|load_arg_regs([], As, I+1)];
load_arg_regs(Rs, [], _) -> Rs.
%% Returns the variables must be saved and are currently in the
%% x registers that are about to be overwritten by the arguments.
unsaved_registers(Regs, Stk, Fb, Lf, Vdb) ->
[V || {V,F,L} <- Vdb,
F < Fb,
L >= Lf,
not on_stack(V, Stk),
not in_reg(V, Regs)].
in_reg(V, Regs) -> keymember(V, 2, Regs).
%% Move away unsaved variables from the registers that are to be
%% overwritten by the arguments.
move_unsaved(Vs, OrigRegs, NewRegs) ->
move_unsaved(Vs, OrigRegs, NewRegs, []).
move_unsaved([V|Vs], OrigRegs, NewRegs0, Acc) ->
NewRegs = put_reg(V, NewRegs0),
Src = fetch_reg(V, OrigRegs),
Dst = fetch_reg(V, NewRegs),
move_unsaved(Vs, OrigRegs, NewRegs, [{move,Src,Dst}|Acc]);
move_unsaved([], _, Regs, Acc) -> {Acc,Regs}.
%% gen_moves(As, Sr)
%% Generate the basic move instruction to move the arguments
%% to their proper registers. The list will be sorted on
%% destinations. (I.e. the move to {x,0} will be first --
%% see the comment to order_moves/2.)
gen_moves(As, Sr) -> gen_moves(As, Sr, 0, []).
gen_moves([#k_var{name=V}|As], Sr, I, Acc) ->
case fetch_var(V, Sr) of
{x,I} -> gen_moves(As, Sr, I+1, Acc);
Reg -> gen_moves(As, Sr, I+1, [{move,Reg,{x,I}}|Acc])
end;
gen_moves([A0|As], Sr, I, Acc) ->
A = atomic(A0),
gen_moves(As, Sr, I+1, [{move,A,{x,I}}|Acc]);
gen_moves([], _, _, Acc) -> lists:keysort(3, Acc).
%% order_moves([Move], ScratchReg) -> [Move]
%% Orders move instruction so that source registers are not
%% destroyed before they are used. If there are cycles
%% (such as {move,{x,0},{x,1}}, {move,{x,1},{x,1}}),
%% the scratch register is used to break up the cycle.
%% If possible, the first move of the input list is placed
%% last in the result list (to make the move to {x,0} occur
%% just before the call to allow the Beam loader to coalesce
%% the instructions).
order_moves(Ms, Scr) -> order_moves(Ms, Scr, []).
order_moves([{move,_,_}=M|Ms0], ScrReg, Acc0) ->
{Chain,Ms} = collect_chain(Ms0, [M], ScrReg),
Acc = reverse(Chain, Acc0),
order_moves(Ms, ScrReg, Acc);
order_moves([], _, Acc) -> Acc.
collect_chain(Ms, Path, ScrReg) ->
collect_chain(Ms, Path, [], ScrReg).
collect_chain([{move,Src,Same}=M|Ms0], [{move,Same,_}|_]=Path, Others, ScrReg) ->
case lists:keyfind(Src, 3, Path) of
false ->
collect_chain(reverse(Others, Ms0), [M|Path], [], ScrReg);
_ -> % We have a cycle.
{break_up_cycle(M, Path, ScrReg),reverse(Others, Ms0)}
end;
collect_chain([M|Ms], Path, Others, ScrReg) ->
collect_chain(Ms, Path, [M|Others], ScrReg);
collect_chain([], Path, Others, _) ->
{Path,Others}.
break_up_cycle({move,Src,_}=M, Path, ScrReg) ->
[{move,ScrReg,Src},M|break_up_cycle1(Src, Path, ScrReg)].
break_up_cycle1(Dst, [{move,Src,Dst}|Path], ScrReg) ->
[{move,Src,ScrReg}|Path];
break_up_cycle1(Dst, [M|Path], LastMove) ->
[M|break_up_cycle1(Dst, Path, LastMove)].
%% clear_dead(Sr, Until, Vdb) -> Aft.
%% Remove all variables in Sr which have died AT ALL so far.
clear_dead(#sr{stk=Stk}=Sr0, Until, Vdb) ->
Sr = Sr0#sr{reg=clear_dead_reg(Sr0, Until, Vdb),
stk=clear_dead_stk(Stk, Until, Vdb)},
reserve(Sr).
clear_dead_reg(Sr, Until, Vdb) ->
[case R of
{_I,V} = IV ->
case vdb_find(V, Vdb) of
{V,_,L} when L > Until -> IV;
_ -> free %Remove anything else
end;
{reserved,_I,_V}=Reserved -> Reserved;
free -> free
end || R <- Sr#sr.reg].
clear_dead_stk(Stk, Until, Vdb) ->
[case S of
{V} = T ->
case vdb_find(V, Vdb) of
{V,_,L} when L > Until -> T;
_ -> dead %Remove anything else
end;
free -> free;
dead -> dead
end || S <- Stk].
%% sr_merge(Sr1, Sr2) -> Sr.
%% Merge two stack/register states keeping the longest of both stack
%% and register. Perform consistency check on both, elements must be
%% the same. Allow frame size 'void' to make easy creation of
%% "empty" frame.
sr_merge(#sr{reg=R1,stk=S1,res=[]}, #sr{reg=R2,stk=S2,res=[]}) ->
#sr{reg=longest(R1, R2),stk=longest(S1, S2),res=[]};
sr_merge(void, S2) -> S2#sr{res=[]}.
longest([H|T1], [H|T2]) -> [H|longest(T1, T2)];
longest([dead|T1], [free|T2]) -> [dead|longest(T1, T2)];
longest([free|T1], [dead|T2]) -> [dead|longest(T1, T2)];
longest([dead|_] = L, []) -> L;
longest([], [dead|_] = L) -> L;
longest([free|_] = L, []) -> L;
longest([], [free|_] = L) -> L;
longest([], []) -> [].
trim_free([R|Rs0]) ->
case {trim_free(Rs0),R} of
{[],free} -> [];
{Rs,R} -> [R|Rs]
end;
trim_free([]) -> [].
%% maybe_adjust_stack(Bef, FirstBefore, LastFrom, Vdb, St) -> {[Ainstr],Aft}.
%% Adjust the stack, but only if the code is inside a catch and not
%% inside a guard. Use this funtion before instructions that may
%% cause an exception.
maybe_adjust_stack(Bef, Fb, Lf, Vdb, St) ->
case St of
#cg{in_catch=true,bfail=0} ->
adjust_stack(Bef, Fb, Lf, Vdb);
#cg{} ->
{[],Bef}
end.
%% adjust_stack(Bef, FirstBefore, LastFrom, Vdb) -> {[Ainstr],Aft}.
%% Do complete stack adjustment by compressing stack and adding
%% variables to be saved. Try to optimise ordering on stack by
%% having reverse order to their lifetimes.
%%
%% In Beam, there is a fixed stack frame and no need to do stack compression.
adjust_stack(Bef, Fb, Lf, Vdb) ->
Stk0 = Bef#sr.stk,
{Stk1,Saves} = save_stack(Stk0, Fb, Lf, Vdb),
{saves(Saves, Bef#sr.reg, Stk1),
Bef#sr{stk=Stk1}}.
%% save_stack(Stack, FirstBefore, LastFrom, Vdb) -> {[SaveVar],NewStack}.
%% Save variables which are used past current point and which are not
%% already on the stack.
save_stack(Stk0, Fb, Lf, Vdb) ->
%% New variables that are in use but not on stack.
New = new_not_on_stack(Stk0, Fb, Lf, Vdb),
%% Add new variables that are not just dropped immediately.
%% N.B. foldr works backwards from the end!!
Saves = [V || {V,_,_} <- keysort(3, New)],
Stk1 = foldr(fun (V, Stk) -> put_stack(V, Stk) end, Stk0, Saves),
{Stk1,Saves}.
%% new_not_on_stack(Stack, FirstBefore, LastFrom, Vdb) ->
%% [{Variable,First,Last}]
%% Return information about all variables that are used past current
%% point and that are not already on the stack.
new_not_on_stack(Stk, Fb, Lf, Vdb) ->
[VFL || {V,F,L} = VFL <- Vdb,
F < Fb,
L >= Lf,
not on_stack(V, Stk)].
%% saves([SaveVar], Reg, Stk) -> [{move,Reg,Stk}].
%% Generate move instructions to save variables onto stack. The
%% stack/reg info used is that after the new stack has been made.
saves(Ss, Reg, Stk) ->
[{move,fetch_reg(V, Reg),fetch_stack(V, Stk)} || V <- Ss].
%% fetch_var(VarName, StkReg) -> r{R} | sp{Sp}.
%% find_var(VarName, StkReg) -> ok{r{R} | sp{Sp}} | error.
%% Fetch/find a variable in either the registers or on the
%% stack. Fetch KNOWS it's there.
fetch_var(V, Sr) ->
case find_reg(V, Sr#sr.reg) of
{ok,R} -> R;
error -> fetch_stack(V, Sr#sr.stk)
end.
fetch_var_prefer_y(V, #sr{reg=Reg,stk=Stk}) ->
case find_stack(V, Stk) of
{ok,R} -> R;
error -> fetch_reg(V, Reg)
end.
load_vars(Vs, Regs) ->
foldl(fun (#k_var{name=V}, Rs) -> put_reg(V, Rs) end, Regs, Vs).
%% put_reg(Val, Regs) -> Regs.
%% find_reg(Val, Regs) -> {ok,r{R}} | error.
%% fetch_reg(Val, Regs) -> r{R}.
%% Functions to interface the registers.
% put_regs(Vs, Rs) -> foldl(fun put_reg/2, Rs, Vs).
put_reg(V, Rs) -> put_reg_1(V, Rs, 0).
put_reg_1(V, [free|Rs], I) -> [{I,V}|Rs];
put_reg_1(V, [{reserved,I,V}|Rs], I) -> [{I,V}|Rs];
put_reg_1(V, [R|Rs], I) -> [R|put_reg_1(V, Rs, I+1)];
put_reg_1(V, [], I) -> [{I,V}].
fetch_reg(V, [{I,V}|_]) -> {x,I};
fetch_reg(V, [_|SRs]) -> fetch_reg(V, SRs).
find_reg(V, [{I,V}|_]) -> {ok,{x,I}};
find_reg(V, [_|SRs]) -> find_reg(V, SRs);
find_reg(_, []) -> error.
%% For the bit syntax, we need a scratch register if we are constructing
%% a binary that will not be used.
find_scratch_reg(Rs) -> find_scratch_reg(Rs, 0).
find_scratch_reg([free|_], I) -> {x,I};
find_scratch_reg([_|Rs], I) -> find_scratch_reg(Rs, I+1);
find_scratch_reg([], I) -> {x,I}.
replace_reg_contents(Old, New, [{I,Old}|Rs]) -> [{I,New}|Rs];
replace_reg_contents(Old, New, [R|Rs]) -> [R|replace_reg_contents(Old, New, Rs)].
%%clear_regs(Regs) -> map(fun (R) -> free end, Regs).
clear_regs(_) -> [].
max_reg(Regs) ->
foldl(fun ({I,_}, _) -> I;
(_, Max) -> Max end,
-1, Regs) + 1.
%% put_stack(Val, [{Val}]) -> [{Val}].
%% fetch_stack(Var, Stk) -> sp{S}.
%% find_stack(Var, Stk) -> ok{sp{S}} | error.
%% Functions to interface the stack.
put_stack(Val, []) -> [{Val}];
put_stack(Val, [dead|Stk]) -> [{Val}|Stk];
put_stack(Val, [free|Stk]) -> [{Val}|Stk];
put_stack(Val, [NotFree|Stk]) -> [NotFree|put_stack(Val, Stk)].
put_stack_carefully(Val, Stk0) ->
try
put_stack_carefully1(Val, Stk0)
catch
throw:error ->
error
end.
put_stack_carefully1(_, []) -> throw(error);
put_stack_carefully1(Val, [dead|Stk]) -> [{Val}|Stk];
put_stack_carefully1(Val, [free|Stk]) -> [{Val}|Stk];
put_stack_carefully1(Val, [NotFree|Stk]) ->
[NotFree|put_stack_carefully1(Val, Stk)].
fetch_stack(Var, Stk) -> fetch_stack(Var, Stk, 0).
fetch_stack(V, [{V}|_], I) -> {yy,I};
fetch_stack(V, [_|Stk], I) -> fetch_stack(V, Stk, I+1).
find_stack(Var, Stk) -> find_stack(Var, Stk, 0).
find_stack(V, [{V}|_], I) -> {ok,{yy,I}};
find_stack(V, [_|Stk], I) -> find_stack(V, Stk, I+1);
find_stack(_, [], _) -> error.
on_stack(V, Stk) -> keymember(V, 1, Stk).
%% put_catch(CatchTag, Stack) -> Stack'
%% drop_catch(CatchTag, Stack) -> Stack'
%% Special interface for putting and removing catch tags, to ensure that
%% catches nest properly. Also used for try tags.
put_catch(Tag, Stk0) -> put_catch(Tag, reverse(Stk0), []).
put_catch(Tag, [], Stk) ->
put_stack({catch_tag,Tag}, Stk);
put_catch(Tag, [{{catch_tag,_}}|_]=RevStk, Stk) ->
reverse(RevStk, put_stack({catch_tag,Tag}, Stk));
put_catch(Tag, [Other|Stk], Acc) ->
put_catch(Tag, Stk, [Other|Acc]).
drop_catch(Tag, [{{catch_tag,Tag}}|Stk]) -> [free|Stk];
drop_catch(Tag, [Other|Stk]) -> [Other|drop_catch(Tag, Stk)].
%% atomic(Klit) -> Lit.
%% atomic_list([Klit]) -> [Lit].
atomic(#k_literal{val=V}) -> {literal,V};
atomic(#k_int{val=I}) -> {integer,I};
atomic(#k_float{val=F}) -> {float,F};
atomic(#k_atom{val=A}) -> {atom,A};
%%atomic(#k_char{val=C}) -> {char,C};
atomic(#k_nil{}) -> nil.
%% new_label(St) -> {L,St}.
new_label(#cg{lcount=Next}=St) ->
{Next,St#cg{lcount=Next+1}}.
%% line(Le) -> {line,[] | {location,File,Line}}
%% Create a line instruction, containing information about
%% the current filename and line number. A line information
%% instruction should be placed before any operation that could
%% cause an exception.
line(#l{a=Anno}) ->
line(Anno);
line([Line,{file,Name}]) when is_integer(Line) ->
line_1(Name, Line);
line([_|_]=A) ->
{Name,Line} = find_loc(A, no_file, 0),
line_1(Name, Line);
line([]) ->
{line,[]}.
line_1(no_file, _) ->
{line,[]};
line_1(_, 0) ->
%% Missing line number or line number 0.
{line,[]};
line_1(Name, Line) ->
{line,[{location,Name,Line}]}.
find_loc([Line|T], File, _) when is_integer(Line) ->
find_loc(T, File, Line);
find_loc([{file,File}|T], _, Line) ->
find_loc(T, File, Line);
find_loc([_|T], File, Line) ->
find_loc(T, File, Line);
find_loc([], File, Line) -> {File,Line}.
flatmapfoldl(F, Accu0, [Hd|Tail]) ->
{R,Accu1} = F(Hd, Accu0),
{Rs,Accu2} = flatmapfoldl(F, Accu1, Tail),
{R++Rs,Accu2};
flatmapfoldl(_, Accu, []) -> {[],Accu}.
%% Keep track of life time for variables.
%%
%% init_vars([{var,VarName}]) -> Vdb.
%% new_vars([VarName], I, Vdb) -> Vdb.
%% use_vars([VarName], I, Vdb) -> Vdb.
%% add_var(VarName, F, L, Vdb) -> Vdb.
%%
%% The list of variable names for new_vars/3 and use_vars/3
%% must be sorted.
init_vars(Vs) ->
vdb_new(Vs).
new_vars([], _, Vdb) -> Vdb;
new_vars([V], I, Vdb) -> vdb_store_new(V, {V,I,I}, Vdb);
new_vars(Vs, I, Vdb) -> vdb_update_vars(Vs, Vdb, I).
use_vars([], _, Vdb) ->
Vdb;
use_vars([V], I, Vdb) ->
case vdb_find(V, Vdb) of
{V,F,L} when I > L -> vdb_update(V, {V,F,I}, Vdb);
{V,_,_} -> Vdb;
error -> vdb_store_new(V, {V,I,I}, Vdb)
end;
use_vars(Vs, I, Vdb) -> vdb_update_vars(Vs, Vdb, I).
add_var(V, F, L, Vdb) ->
vdb_store_new(V, {V,F,L}, Vdb).
%% vdb
vdb_new(Vs) ->
ordsets:from_list([{V,0,0} || #k_var{name=V} <- Vs]).
-type var() :: atom().
-spec vdb_find(var(), [vdb_entry()]) -> 'error' | vdb_entry().
vdb_find(V, Vdb) ->
case lists:keyfind(V, 1, Vdb) of
false -> error;
Vd -> Vd
end.
vdb_update(V, Update, [{V,_,_}|Vdb]) ->
[Update|Vdb];
vdb_update(V, Update, [Vd|Vdb]) ->
[Vd|vdb_update(V, Update, Vdb)].
vdb_store_new(V, New, [{V1,_,_}=Vd|Vdb]) when V > V1 ->
[Vd|vdb_store_new(V, New, Vdb)];
vdb_store_new(V, New, [{V1,_,_}|_]=Vdb) when V < V1 ->
[New|Vdb];
vdb_store_new(_, New, []) -> [New].
vdb_update_vars([V|_]=Vs, [{V1,_,_}=Vd|Vdb], I) when V > V1 ->
[Vd|vdb_update_vars(Vs, Vdb, I)];
vdb_update_vars([V|Vs], [{V1,_,_}|_]=Vdb, I) when V < V1 ->
%% New variable.
[{V,I,I}|vdb_update_vars(Vs, Vdb, I)];
vdb_update_vars([V|Vs], [{_,F,L}=Vd|Vdb], I) ->
%% Existing variable.
if
I > L -> [{V,F,I}|vdb_update_vars(Vs, Vdb, I)];
true -> [Vd|vdb_update_vars(Vs, Vdb, I)]
end;
vdb_update_vars([V|Vs], [], I) ->
%% New variable.
[{V,I,I}|vdb_update_vars(Vs, [], I)];
vdb_update_vars([], Vdb, _) -> Vdb.
%% vdb_sub(Min, Max, Vdb) -> Vdb.
%% Extract variables which are used before and after Min. Lock
%% variables alive after Max.
vdb_sub(Min, Max, Vdb) ->
[ if L >= Max -> {V,F,locked};
true -> Vd
end || {V,F,L}=Vd <- Vdb,
F < Min,
L >= Min ].
