%% -*- erlang-indent-level: 2 -*-
%%
%% 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.
-module(hipe_arm_frame).
-export([frame/1]).
-include("hipe_arm.hrl").
-include("../rtl/hipe_literals.hrl").
-define(LIVENESS_ALL, hipe_arm_liveness_gpr). % since we have no FP yet
frame(CFG) ->
Formals = fix_formals(hipe_arm_cfg:params(CFG)),
Temps0 = all_temps(CFG, Formals),
MinFrame = defun_minframe(CFG),
Temps = ensure_minframe(MinFrame, Temps0),
ClobbersLR = clobbers_lr(CFG),
Liveness = ?LIVENESS_ALL:analyse(CFG),
do_body(CFG, Liveness, Formals, Temps, ClobbersLR).
fix_formals(Formals) ->
fix_formals(hipe_arm_registers:nr_args(), Formals).
fix_formals(0, Rest) -> Rest;
fix_formals(N, [_|Rest]) -> fix_formals(N-1, Rest);
fix_formals(_, []) -> [].
do_body(CFG0, Liveness, Formals, Temps, ClobbersLR) ->
Context = mk_context(Liveness, Formals, Temps, ClobbersLR),
CFG1 = do_blocks(CFG0, Context),
do_prologue(CFG1, Context).
do_blocks(CFG, Context) ->
hipe_arm_cfg:map_bbs(fun(Lbl, BB) -> do_block(Lbl, BB, Context) end, CFG).
do_block(Label, Block, Context) ->
Liveness = context_liveness(Context),
LiveOut = ?LIVENESS_ALL:liveout(Liveness, Label),
Code = hipe_bb:code(Block),
NewCode = do_block(Code, LiveOut, Context, context_framesize(Context), []),
hipe_bb:code_update(Block, NewCode).
do_block([I|Insns], LiveOut, Context, FPoff0, RevCode) ->
{NewIs, FPoff1} = do_insn(I, LiveOut, Context, FPoff0),
do_block(Insns, LiveOut, Context, FPoff1, lists:reverse(NewIs, RevCode));
do_block([], _, Context, FPoff, RevCode) ->
FPoff0 = context_framesize(Context),
FPoff0 = FPoff,
lists:reverse(RevCode, []).
do_insn(I, LiveOut, Context, FPoff) ->
case I of
#pseudo_blr{} ->
{do_pseudo_blr(I, Context, FPoff), context_framesize(Context)};
#pseudo_call{} ->
do_pseudo_call(I, LiveOut, Context, FPoff);
#pseudo_call_prepare{} ->
do_pseudo_call_prepare(I, FPoff);
#pseudo_move{} ->
{do_pseudo_move(I, Context, FPoff), FPoff};
#pseudo_tailcall{} ->
{do_pseudo_tailcall(I, Context), context_framesize(Context)};
_ ->
{[I], FPoff}
end.
%%%
%%% Moves, with Dst or Src possibly a pseudo
%%%
do_pseudo_move(I, Context, FPoff) ->
Dst = hipe_arm:pseudo_move_dst(I),
Src = hipe_arm:pseudo_move_src(I),
case temp_is_pseudo(Dst) of
true ->
Offset = pseudo_offset(Dst, FPoff, Context),
mk_store('str', Src, Offset, mk_sp(), []);
_ ->
case temp_is_pseudo(Src) of
true ->
Offset = pseudo_offset(Src, FPoff, Context),
mk_load('ldr', Dst, Offset, mk_sp(), []);
_ ->
[hipe_arm:mk_move(Dst, Src)]
end
end.
pseudo_offset(Temp, FPoff, Context) ->
FPoff + context_offset(Context, Temp).
%%%
%%% Return - deallocate frame and emit 'ret $N' insn.
%%%
do_pseudo_blr(I, Context, FPoff) ->
%% XXX: perhaps use explicit pseudo_move;mtlr,
%% avoiding the need to hard-code Temp1 here
%% XXX: typically only one instruction between
%% the mtlr and the blr, ouch
restore_lr(FPoff, Context,
adjust_sp(FPoff + word_size() * context_arity(Context),
[I])).
restore_lr(FPoff, Context, Rest) ->
case context_clobbers_lr(Context) of
false -> Rest;
true ->
LR = hipe_arm:mk_lr(),
mk_load('ldr', LR, FPoff - word_size(), mk_sp(),
Rest)
end.
adjust_sp(N, Rest) ->
if N =:= 0 ->
Rest;
true ->
SP = mk_sp(),
hipe_arm:mk_addi(SP, SP, N, Rest)
end.
%%%
%%% Recursive calls.
%%%
do_pseudo_call_prepare(I, FPoff0) ->
%% Create outgoing arguments area on the stack.
NrStkArgs = hipe_arm:pseudo_call_prepare_nrstkargs(I),
Offset = NrStkArgs * word_size(),
{adjust_sp(-Offset, []), FPoff0 + Offset}.
do_pseudo_call(I, LiveOut, Context, FPoff0) ->
#arm_sdesc{exnlab=ExnLab,arity=OrigArity} = hipe_arm:pseudo_call_sdesc(I),
FunV = hipe_arm:pseudo_call_funv(I),
LiveTemps = [Temp || Temp <- LiveOut, temp_is_pseudo(Temp)],
SDesc = mk_sdesc(ExnLab, Context, LiveTemps),
ContLab = hipe_arm:pseudo_call_contlab(I),
Linkage = hipe_arm:pseudo_call_linkage(I),
CallCode = [hipe_arm:mk_pseudo_call(FunV, SDesc, ContLab, Linkage)],
StkArity = erlang:max(0, OrigArity - hipe_arm_registers:nr_args()),
context_need_stack(Context, stack_need(FPoff0, StkArity, FunV)),
ArgsBytes = word_size() * StkArity,
{CallCode, FPoff0 - ArgsBytes}.
stack_need(FPoff, StkArity, FunV) ->
case FunV of
#arm_prim{} -> FPoff;
#arm_mfa{m=M,f=F,a=A} ->
case erlang:is_builtin(M, F, A) of
true -> FPoff;
false -> stack_need_general(FPoff, StkArity)
end;
_ -> stack_need_general(FPoff, StkArity)
end.
stack_need_general(FPoff, StkArity) ->
erlang:max(FPoff, FPoff + (?ARM_LEAF_WORDS - StkArity) * word_size()).
%%%
%%% Create stack descriptors for call sites.
%%%
mk_sdesc(ExnLab, Context, Temps) -> % for normal calls
Temps0 = only_tagged(Temps),
Live = mk_live(Context, Temps0),
Arity = context_arity(Context),
FSize = context_framesize(Context),
hipe_arm:mk_sdesc(ExnLab, (FSize div word_size())-1, Arity,
list_to_tuple(Live)).
only_tagged(Temps)->
[X || X <- Temps, hipe_arm:temp_type(X) =:= 'tagged'].
mk_live(Context, Temps) ->
lists:sort([temp_to_slot(Context, Temp) || Temp <- Temps]).
temp_to_slot(Context, Temp) ->
(context_framesize(Context) + context_offset(Context, Temp))
div word_size().
mk_minimal_sdesc(Context) -> % for inc_stack_0 calls
hipe_arm:mk_sdesc([], 0, context_arity(Context), {}).
%%%
%%% Tailcalls.
%%%
do_pseudo_tailcall(I, Context) -> % always at FPoff=context_framesize(Context)
Arity = context_arity(Context),
Args = hipe_arm:pseudo_tailcall_stkargs(I),
FunV = hipe_arm:pseudo_tailcall_funv(I),
Linkage = hipe_arm:pseudo_tailcall_linkage(I),
{Insns, FPoff1} = do_tailcall_args(Args, Context),
context_need_stack(Context, FPoff1),
StkArity = length(Args),
FPoff2 = FPoff1 + (Arity - StkArity) * word_size(),
context_need_stack(Context, stack_need(FPoff2, StkArity, FunV)),
I2 =
case FunV of
#arm_temp{} ->
hipe_arm:mk_bx(FunV);
Fun ->
hipe_arm:mk_b_fun(Fun, Linkage)
end,
%% XXX: break out the LR restore, just like for pseudo_blr?
restore_lr(context_framesize(Context), Context,
Insns ++ adjust_sp(FPoff2, [I2])).
do_tailcall_args(Args, Context) ->
FPoff0 = context_framesize(Context),
Arity = context_arity(Context),
FrameTop = word_size()*Arity,
DangerOff = FrameTop - word_size()*length(Args),
%%
Moves = mk_moves(Args, FrameTop, []),
%%
{Stores, Simple, Conflict} =
split_moves(Moves, Context, DangerOff, [], [], []),
%% sanity check (shouldn't trigger any more)
if DangerOff < -FPoff0 ->
exit({?MODULE,do_tailcall_args,DangerOff,-FPoff0});
true -> []
end,
FPoff1 = FPoff0,
%%
{Pushes, Pops, FPoff2} = split_conflict(Conflict, FPoff1, [], []),
%%
TempReg = hipe_arm_registers:temp1(),
%%
{adjust_sp(-(FPoff2 - FPoff1),
simple_moves(Pushes, FPoff2, TempReg,
store_moves(Stores, FPoff2, TempReg,
simple_moves(Simple, FPoff2, TempReg,
simple_moves(Pops, FPoff2, TempReg,
[]))))),
FPoff2}.
mk_moves([Arg|Args], Off, Moves) ->
Off1 = Off - word_size(),
mk_moves(Args, Off1, [{Arg,Off1}|Moves]);
mk_moves([], _, Moves) ->
Moves.
split_moves([Move|Moves], Context, DangerOff, Stores, Simple, Conflict) ->
{Src,DstOff} = Move,
case src_is_pseudo(Src) of
false ->
split_moves(Moves, Context, DangerOff, [Move|Stores],
Simple, Conflict);
true ->
SrcOff = context_offset(Context, Src),
Type = typeof_temp(Src),
if SrcOff =:= DstOff ->
split_moves(Moves, Context, DangerOff, Stores,
Simple, Conflict);
SrcOff >= DangerOff ->
split_moves(Moves, Context, DangerOff, Stores,
Simple, [{SrcOff,DstOff,Type}|Conflict]);
true ->
split_moves(Moves, Context, DangerOff, Stores,
[{SrcOff,DstOff,Type}|Simple], Conflict)
end
end;
split_moves([], _, _, Stores, Simple, Conflict) ->
{Stores, Simple, Conflict}.
split_conflict([{SrcOff,DstOff,Type}|Conflict], FPoff, Pushes, Pops) ->
FPoff1 = FPoff + word_size(),
Push = {SrcOff,-FPoff1,Type},
Pop = {-FPoff1,DstOff,Type},
split_conflict(Conflict, FPoff1, [Push|Pushes], [Pop|Pops]);
split_conflict([], FPoff, Pushes, Pops) ->
{lists:reverse(Pushes), Pops, FPoff}.
simple_moves([{SrcOff,DstOff,Type}|Moves], FPoff, TempReg, Rest) ->
Temp = hipe_arm:mk_temp(TempReg, Type),
SP = mk_sp(),
LoadOff = FPoff+SrcOff,
StoreOff = FPoff+DstOff,
simple_moves(Moves, FPoff, TempReg,
mk_load('ldr', Temp, LoadOff, SP,
mk_store('str', Temp, StoreOff, SP,
Rest)));
simple_moves([], _, _, Rest) ->
Rest.
store_moves([{Src,DstOff}|Moves], FPoff, TempReg, Rest) ->
%%Type = typeof_temp(Src),
SP = mk_sp(),
StoreOff = FPoff+DstOff,
{NewSrc,FixSrc} =
case hipe_arm:is_temp(Src) of
true ->
{Src, []};
_ ->
Temp = hipe_arm:mk_temp(TempReg, 'untagged'),
{Temp, hipe_arm:mk_li(Temp, Src)}
end,
store_moves(Moves, FPoff, TempReg,
FixSrc ++ mk_store('str', NewSrc, StoreOff, SP, Rest));
store_moves([], _, _, Rest) ->
Rest.
%%%
%%% Contexts
%%%
-record(context, {liveness, framesize, arity, map, clobbers_lr, ref_maxstack}).
mk_context(Liveness, Formals, Temps, ClobbersLR) ->
{Map, MinOff} = mk_temp_map(Formals, ClobbersLR, Temps),
FrameSize = (-MinOff),
RefMaxStack = hipe_bifs:ref(FrameSize),
#context{liveness=Liveness,
framesize=FrameSize, arity=length(Formals),
map=Map, clobbers_lr=ClobbersLR, ref_maxstack=RefMaxStack}.
context_need_stack(#context{ref_maxstack=RM}, N) ->
M = hipe_bifs:ref_get(RM),
if N > M -> hipe_bifs:ref_set(RM, N);
true -> []
end.
context_maxstack(#context{ref_maxstack=RM}) ->
hipe_bifs:ref_get(RM).
context_arity(#context{arity=Arity}) ->
Arity.
context_framesize(#context{framesize=FrameSize}) ->
FrameSize.
context_liveness(#context{liveness=Liveness}) ->
Liveness.
context_offset(#context{map=Map}, Temp) ->
tmap_lookup(Map, Temp).
context_clobbers_lr(#context{clobbers_lr=ClobbersLR}) -> ClobbersLR.
mk_temp_map(Formals, ClobbersLR, Temps) ->
{Map, 0} = enter_vars(Formals, word_size() * length(Formals),
tmap_empty()),
TempsList = tset_to_list(Temps),
AllTemps =
case ClobbersLR of
false -> TempsList;
true ->
RA = hipe_arm:mk_new_temp('untagged'),
[RA|TempsList]
end,
enter_vars(AllTemps, 0, Map).
enter_vars([V|Vs], PrevOff, Map) ->
Off =
case hipe_arm:temp_type(V) of
'double' -> PrevOff - 2*word_size();
_ -> PrevOff - word_size()
end,
enter_vars(Vs, Off, tmap_bind(Map, V, Off));
enter_vars([], Off, Map) ->
{Map, Off}.
tmap_empty() ->
gb_trees:empty().
tmap_bind(Map, Key, Val) ->
gb_trees:insert(Key, Val, Map).
tmap_lookup(Map, Key) ->
gb_trees:get(Key, Map).
%%%
%%% do_prologue: prepend stack frame allocation code.
%%%
%%% NewStart:
%%% temp1 = *(P + P_SP_LIMIT)
%%% temp2 = SP - MaxStack
%%% cmp temp2, temp1
%%% if (ltu) goto IncStack else goto AllocFrame
%%% AllocFrame:
%%% SP = temp2 [if FrameSize == MaxStack]
%%% SP -= FrameSize [if FrameSize != MaxStack]
%%% *(SP + FrameSize-WordSize) = LR [if ClobbersLR]
%%% goto OldStart
%%% OldStart:
%%% ...
%%% IncStack:
%%% temp1 = LR
%%% bl inc_stack
%%% LR = temp1
%%% goto NewStart
do_prologue(CFG, Context) ->
MaxStack = context_maxstack(Context),
if MaxStack > 0 ->
FrameSize = context_framesize(Context),
OldStartLab = hipe_arm_cfg:start_label(CFG),
NewStartLab = hipe_gensym:get_next_label(arm),
%%
P = hipe_arm:mk_temp(hipe_arm_registers:proc_pointer(), 'untagged'),
Temp1 = mk_temp1(),
SP = mk_sp(),
%%
LR = hipe_arm:mk_lr(),
ClobbersLR = context_clobbers_lr(Context),
GotoOldStartCode = [hipe_arm:mk_b_label(OldStartLab)],
AllocFrameCodeTail =
case ClobbersLR of
false -> GotoOldStartCode;
true -> mk_store('str', LR, FrameSize-word_size(), SP, GotoOldStartCode)
end,
%%
Arity = context_arity(Context),
Guaranteed = erlang:max(0, (?ARM_LEAF_WORDS - Arity) * word_size()),
%%
{CFG1,NewStartCode} =
if MaxStack =< Guaranteed ->
%% io:format("~w: MaxStack ~w =< Guaranteed ~w :-)\n", [?MODULE,MaxStack,Guaranteed]),
AllocFrameCode = adjust_sp(-FrameSize, AllocFrameCodeTail),
NewStartCode0 = AllocFrameCode, % no mflr needed
{CFG,NewStartCode0};
true ->
%% io:format("~w: MaxStack ~w > Guaranteed ~w :-(\n", [?MODULE,MaxStack,Guaranteed]),
AllocFrameLab = hipe_gensym:get_next_label(arm),
IncStackLab = hipe_gensym:get_next_label(arm),
Temp2 = mk_temp2(),
%%
NewStartCodeTail2 =
[hipe_arm:mk_pseudo_bc('lo', IncStackLab, AllocFrameLab, 0.01)],
NewStartCodeTail1 = NewStartCodeTail2, % no mflr needed
NewStartCode0 =
mk_load('ldr', Temp1, ?P_NSP_LIMIT, P,
hipe_arm:mk_addi(Temp2, SP, -MaxStack,
[hipe_arm:mk_cmp('cmp', Temp2, Temp1) |
NewStartCodeTail1])),
%%
AllocFrameCode =
if MaxStack =:= FrameSize ->
%% io:format("~w: MaxStack =:= FrameSize =:= ~w :-)\n", [?MODULE,MaxStack]),
[hipe_arm:mk_move(SP, Temp2) |
AllocFrameCodeTail];
true ->
%% io:format("~w: MaxStack ~w =/= FrameSize ~w :-(\n", [?MODULE,MaxStack,FrameSize]),
adjust_sp(-FrameSize, AllocFrameCodeTail)
end,
%%
IncStackCodeTail =
[hipe_arm:mk_bl(hipe_arm:mk_prim('inc_stack_0'),
mk_minimal_sdesc(Context), not_remote),
hipe_arm:mk_mtlr(Temp1),
hipe_arm:mk_b_label(NewStartLab)],
IncStackCode =
[hipe_arm:mk_mflr(Temp1) | IncStackCodeTail], % mflr always needed
%%
CFG0a = hipe_arm_cfg:bb_add(CFG, AllocFrameLab,
hipe_bb:mk_bb(AllocFrameCode)),
CFG0b = hipe_arm_cfg:bb_add(CFG0a, IncStackLab,
hipe_bb:mk_bb(IncStackCode)),
%%
{CFG0b,NewStartCode0}
end,
%%
CFG2 = hipe_arm_cfg:bb_add(CFG1, NewStartLab,
hipe_bb:mk_bb(NewStartCode)),
hipe_arm_cfg:start_label_update(CFG2, NewStartLab);
true ->
CFG
end.
%%% Create a load instruction.
%%% May clobber Dst early for large offsets. In principle we could
%%% clobber TEMP2 if Dst =:= Base, but Dst =/= Base here in frame.
mk_load(LdOp, Dst, Offset, Base, Rest) ->
hipe_arm:mk_load(LdOp, Dst, Base, Offset, 'error', Rest).
%%% Create a store instruction.
%%% May clobber TEMP2 for large offsets.
mk_store(StOp, Src, Offset, Base, Rest) ->
hipe_arm:mk_store(StOp, Src, Base, Offset, 'temp2', Rest).
%%% typeof_temp -- what's temp's type?
typeof_temp(Temp) ->
hipe_arm:temp_type(Temp).
%%% Cons up an 'SP' Temp.
mk_sp() ->
hipe_arm:mk_temp(hipe_arm_registers:stack_pointer(), 'untagged').
%%% Cons up a 'TEMP1' Temp.
mk_temp1() ->
hipe_arm:mk_temp(hipe_arm_registers:temp1(), 'untagged').
%%% Cons up a 'TEMP2' Temp.
mk_temp2() ->
hipe_arm:mk_temp(hipe_arm_registers:temp2(), 'untagged').
%%% Check if an operand is a pseudo-Temp.
src_is_pseudo(Src) ->
hipe_arm:is_temp(Src) andalso temp_is_pseudo(Src).
temp_is_pseudo(Temp) ->
not(hipe_arm:temp_is_precoloured(Temp)).
%%%
%%% Detect if a Defun's body clobbers LR.
%%%
clobbers_lr(CFG) ->
LRreg = hipe_arm_registers:lr(),
LRtagged = hipe_arm:mk_temp(LRreg, 'tagged'),
LRuntagged = hipe_arm:mk_temp(LRreg, 'untagged'),
any_insn(fun(I) ->
Defs = hipe_arm_defuse:insn_def_gpr(I),
lists:member(LRtagged, Defs)
orelse lists:member(LRuntagged, Defs)
end, CFG).
any_insn(Pred, CFG) ->
%% Abuse fold to do an efficient "any"-operation using nonlocal control flow
FoundSatisfying = make_ref(),
try fold_insns(fun (I, _) ->
case Pred(I) of
true -> throw(FoundSatisfying);
false -> false
end
end, false, CFG)
of _ -> false
catch FoundSatisfying -> true
end.
%%%
%%% Build the set of all temps used in a Defun's body.
%%%
all_temps(CFG, Formals) ->
S0 = fold_insns(fun find_temps/2, tset_empty(), CFG),
S1 = tset_del_list(S0, Formals),
tset_filter(S1, fun(T) -> temp_is_pseudo(T) end).
find_temps(I, S0) ->
S1 = tset_add_list(S0, hipe_arm_defuse:insn_def_all(I)),
tset_add_list(S1, hipe_arm_defuse:insn_use_all(I)).
fold_insns(Fun, InitAcc, CFG) ->
hipe_arm_cfg:fold_bbs(
fun(_, BB, Acc0) -> lists:foldl(Fun, Acc0, hipe_bb:code(BB)) end,
InitAcc, CFG).
tset_empty() ->
gb_sets:new().
tset_size(S) ->
gb_sets:size(S).
tset_insert(S, T) ->
gb_sets:add_element(T, S).
tset_add_list(S, Ts) ->
gb_sets:union(S, gb_sets:from_list(Ts)).
tset_del_list(S, Ts) ->
gb_sets:subtract(S, gb_sets:from_list(Ts)).
tset_filter(S, F) ->
gb_sets:filter(F, S).
tset_to_list(S) ->
gb_sets:to_list(S).
%%%
%%% Compute minimum permissible frame size, ignoring spilled temps.
%%% This is done to ensure that we won't have to adjust the frame size
%%% in the middle of a tailcall.
%%%
defun_minframe(CFG) ->
MaxTailArity = fold_insns(fun insn_mta/2, 0, CFG),
MyArity = length(fix_formals(hipe_arm_cfg:params(CFG))),
erlang:max(MaxTailArity - MyArity, 0).
insn_mta(I, MTA) ->
case I of
#pseudo_tailcall{arity=Arity} ->
erlang:max(MTA, Arity - hipe_arm_registers:nr_args());
_ -> MTA
end.
%%%
%%% Ensure that we have enough temps to satisfy the minimum frame size,
%%% if necessary by prepending unused dummy temps.
%%%
ensure_minframe(MinFrame, Temps) ->
ensure_minframe(MinFrame, tset_size(Temps), Temps).
ensure_minframe(MinFrame, Frame, Temps) ->
if MinFrame > Frame ->
Temp = hipe_arm:mk_new_temp('untagged'),
ensure_minframe(MinFrame, Frame+1, tset_insert(Temps, Temp));
true -> Temps
end.
word_size() ->
4.
