%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2004-2018. 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%
-module(beam_validator).
-include("beam_types.hrl").
-define(UNICODE_MAX, (16#10FFFF)).
-compile({no_auto_import,[min/2]}).
%% Avoid warning for local function error/1 clashing with autoimported BIF.
-compile({no_auto_import,[error/1]}).
%% Interface for compiler.
-export([module/2, format_error/1]).
-import(lists, [dropwhile/2,foldl/3,member/2,reverse/1,sort/1,zip/2]).
%% To be called by the compiler.
-spec module(beam_utils:module_code(), [compile:option()]) ->
{'ok',beam_utils:module_code()}.
module({Mod,Exp,Attr,Fs,Lc}=Code, _Opts)
when is_atom(Mod), is_list(Exp), is_list(Attr), is_integer(Lc) ->
case validate(Mod, Fs) of
[] ->
{ok,Code};
Es0 ->
Es = [{?MODULE,E} || E <- Es0],
{error,[{atom_to_list(Mod),Es}]}
end.
-spec format_error(term()) -> iolist().
format_error({{_M,F,A},{I,Off,limit}}) ->
io_lib:format(
"function ~p/~p+~p:~n"
" An implementation limit was reached.~n"
" Try reducing the complexity of this function.~n~n"
" Instruction: ~p~n", [F,A,Off,I]);
format_error({{_M,F,A},{undef_labels,Lbls}}) ->
io_lib:format(
"function ~p/~p:~n"
" Internal consistency check failed - please report this bug.~n"
" The following label(s) were referenced but not defined:~n", [F,A]) ++
" " ++ [[integer_to_list(L)," "] || L <- Lbls] ++ "\n";
format_error({{_M,F,A},{I,Off,Desc}}) ->
io_lib:format(
"function ~p/~p+~p:~n"
" Internal consistency check failed - please report this bug.~n"
" Instruction: ~p~n"
" Error: ~p:~n", [F,A,Off,I,Desc]);
format_error(Error) ->
io_lib:format("~p~n", [Error]).
%%%
%%% Local functions follow.
%%%
%%%
%%% The validator follows.
%%%
%%% The purpose of the validator is to find errors in the generated
%%% code that may cause the emulator to crash or behave strangely.
%%% We don't care about type errors in the user's code that will
%%% cause a proper exception at run-time.
%%%
%%% Things currently not checked. XXX
%%%
%%% - Heap allocation for binaries.
%%%
%% validate(Module, [Function]) -> [] | [Error]
%% A list of functions with their code. The code is in the same
%% format as used in the compiler and in .S files.
validate(Module, Fs) ->
Ft = build_function_table(Fs, []),
validate_0(Module, Fs, Ft).
validate_0(_Module, [], _) -> [];
validate_0(Module, [{function,Name,Ar,Entry,Code}|Fs], Ft) ->
try validate_1(Code, Name, Ar, Entry, Ft) of
_ -> validate_0(Module, Fs, Ft)
catch
throw:Error ->
%% Controlled error.
[Error|validate_0(Module, Fs, Ft)];
Class:Error:Stack ->
%% Crash.
io:fwrite("Function: ~w/~w\n", [Name,Ar]),
erlang:raise(Class, Error, Stack)
end.
-record(t_abstract, {kind}).
%% The types are the same as in 'beam_types.hrl', with the addition of
%% #t_abstract{} that describes tuples under construction, match context
%% positions, and so on.
-type validator_type() :: #t_abstract{} | type().
-record(value_ref, {id :: index()}).
-record(value, {op :: term(), args :: [argument()], type :: validator_type()}).
-type argument() :: #value_ref{} | literal().
-type index() :: non_neg_integer().
-type literal() :: {atom, [] | atom()} |
{float, [] | float()} |
{integer, [] | integer()} |
{literal, term()} |
nil.
%% Register tags describe the state of the register rather than the value they
%% contain (if any).
%%
%% initialized The register has been initialized with some valid term
%% so that it is safe to pass to the garbage collector.
%% NOT safe to use in any other way (will not crash the
%% emulator, but clearly points to a bug in the compiler).
%%
%% uninitialized The register contains any old garbage and can not be
%% passed to the garbage collector.
%%
%% {catchtag,[Lbl]} A special term used within a catch. Must only be used
%% by the catch instructions; NOT safe to use in other
%% instructions.
%%
%% {trytag,[Lbl]} A special term used within a try block. Must only be
%% used by the catch instructions; NOT safe to use in other
%% instructions.
-type tag() :: initialized |
uninitialized |
{catchtag, [label()]} |
{trytag, [label()]}.
-type x_regs() :: #{ {x, index()} => #value_ref{} }.
-type y_regs() :: #{ {y, index()} => tag() | #value_ref{} }.
%% Emulation state
-record(st,
{%% All known values.
vs=#{} :: #{ #value_ref{} => #value{} },
%% Register states.
xs=#{} :: x_regs(),
ys=#{} :: y_regs(),
f=init_fregs(),
%% A set of all registers containing "fragile" terms. That is, terms
%% that don't exist on our process heap and would be destroyed by a
%% GC.
fragile=cerl_sets:new() :: cerl_sets:set(),
%% Number of Y registers.
%%
%% Note that this may be 0 if there's a frame without saved values,
%% such as on a body-recursive call.
numy=none :: none | undecided | index(),
%% Available heap size.
h=0,
%%Available heap size for floats.
hf=0,
%% Floating point state.
fls=undefined,
%% List of hot catch/try labels
ct=[],
%% Previous instruction was setelement/3.
setelem=false,
%% put/1 instructions left.
puts_left=none
}).
-type label() :: integer().
-type label_set() :: gb_sets:set(label()).
-type branched_tab() :: gb_trees:tree(label(), #st{}).
-type ft_tab() :: gb_trees:tree().
%% Validator state
-record(vst,
{%% Current state
current=none :: #st{} | 'none',
%% States at labels
branched=gb_trees:empty() :: branched_tab(),
%% All defined labels
labels=gb_sets:empty() :: label_set(),
%% Information of other functions in the module
ft=gb_trees:empty() :: ft_tab(),
%% Counter for #value_ref{} creation
ref_ctr=0 :: index()
}).
build_function_table([{function,_,Arity,Entry,Code0}|Fs], Acc0) ->
Code = dropwhile(fun({label,L}) when L =:= Entry -> false;
(_) -> true
end, Code0),
case Code of
[{label,Entry}|Is] ->
Info = #{ arity => Arity,
parameter_types => find_parameter_types(Is, #{}) },
build_function_table(Fs, [{Entry, Info} | Acc0]);
_ ->
%% Something is seriously wrong. Ignore it for now.
%% It will be detected and diagnosed later.
build_function_table(Fs, Acc0)
end;
build_function_table([], Acc) ->
gb_trees:from_orddict(sort(Acc)).
find_parameter_types([{'%', {type_info, Reg, Type}} | Is], Acc) ->
find_parameter_types(Is, Acc#{ Reg => Type });
find_parameter_types(_, Acc) ->
Acc.
validate_1(Is, Name, Arity, Entry, Ft) ->
validate_2(labels(Is), Name, Arity, Entry, Ft).
validate_2({Ls1,[{func_info,{atom,Mod},{atom,Name},Arity}=_F|Is]},
Name, Arity, Entry, Ft) ->
validate_3(labels(Is), Name, Arity, Entry, Mod, Ls1, Ft);
validate_2({Ls1,Is}, Name, Arity, _Entry, _Ft) ->
error({{'_',Name,Arity},{first(Is),length(Ls1),illegal_instruction}}).
validate_3({Ls2,Is}, Name, Arity, Entry, Mod, Ls1, Ft) ->
Offset = 1 + length(Ls1) + 1 + length(Ls2),
EntryOK = member(Entry, Ls2),
if
EntryOK ->
Vst0 = init_vst(Arity, Ls1, Ls2, Ft),
MFA = {Mod,Name,Arity},
Vst = valfun(Is, MFA, Offset, Vst0),
validate_fun_info_branches(Ls1, MFA, Vst);
true ->
error({{Mod,Name,Arity},{first(Is),Offset,no_entry_label}})
end.
validate_fun_info_branches([L|Ls], MFA, #vst{branched=Branches}=Vst0) ->
Vst = Vst0#vst{current=gb_trees:get(L, Branches)},
validate_fun_info_branches_1(0, MFA, Vst),
validate_fun_info_branches(Ls, MFA, Vst);
validate_fun_info_branches([], _, _) -> ok.
validate_fun_info_branches_1(Arity, {_,_,Arity}, _) -> ok;
validate_fun_info_branches_1(X, {Mod,Name,Arity}=MFA, Vst) ->
try
case Vst of
#vst{current=#st{numy=none}} ->
ok;
#vst{current=#st{numy=Size}} ->
error({unexpected_stack_frame,Size})
end,
assert_term({x,X}, Vst)
catch Error ->
I = {func_info,{atom,Mod},{atom,Name},Arity},
Offset = 2,
error({MFA,{I,Offset,Error}})
end,
validate_fun_info_branches_1(X+1, MFA, Vst).
first([X|_]) -> X;
first([]) -> [].
labels(Is) ->
labels_1(Is, []).
labels_1([{label,L}|Is], R) ->
labels_1(Is, [L|R]);
labels_1([{line,_}|Is], R) ->
labels_1(Is, R);
labels_1(Is, R) ->
{reverse(R),Is}.
init_vst(Arity, Ls1, Ls2, Ft) ->
Vst0 = init_function_args(Arity - 1, #vst{current=#st{}}),
Branches = gb_trees_from_list([{L,Vst0#vst.current} || L <- Ls1]),
Labels = gb_sets:from_list(Ls1++Ls2),
Vst0#vst{branched=Branches,
labels=Labels,
ft=Ft}.
init_function_args(-1, Vst) ->
Vst;
init_function_args(X, Vst) ->
init_function_args(X - 1, create_term(any, argument, [], {x,X}, Vst)).
kill_heap_allocation(St) ->
St#st{h=0,hf=0}.
valfun([], MFA, _Offset, #vst{branched=Targets0,labels=Labels0}=Vst) ->
Targets = gb_trees:keys(Targets0),
Labels = gb_sets:to_list(Labels0),
case Targets -- Labels of
[] -> Vst;
Undef ->
Error = {undef_labels,Undef},
error({MFA,Error})
end;
valfun([I|Is], MFA, Offset, Vst0) ->
valfun(Is, MFA, Offset+1,
try
Vst = val_dsetel(I, Vst0),
valfun_1(I, Vst)
catch Error ->
error({MFA,{I,Offset,Error}})
end).
%% Instructions that are allowed in dead code or when failing,
%% that is while the state is undecided in some way.
valfun_1({label,Lbl}, #vst{current=St0,
ref_ctr=Counter0,
branched=B,
labels=Lbls}=Vst) ->
{St, Counter} = merge_states(Lbl, St0, B, Counter0),
Vst#vst{current=St,
ref_ctr=Counter,
branched=gb_trees:enter(Lbl, St, B),
labels=gb_sets:add(Lbl, Lbls)};
valfun_1(_I, #vst{current=none}=Vst) ->
%% Ignore instructions after erlang:error/1,2, which
%% the original R10B compiler thought would return.
Vst;
valfun_1({badmatch,Src}, Vst) ->
assert_durable_term(Src, Vst),
verify_y_init(Vst),
kill_state(Vst);
valfun_1({case_end,Src}, Vst) ->
assert_durable_term(Src, Vst),
verify_y_init(Vst),
kill_state(Vst);
valfun_1(if_end, Vst) ->
verify_y_init(Vst),
kill_state(Vst);
valfun_1({try_case_end,Src}, Vst) ->
verify_y_init(Vst),
assert_durable_term(Src, Vst),
kill_state(Vst);
%% Instructions that cannot cause exceptions
valfun_1({bs_get_tail,Ctx,Dst,Live}, Vst0) ->
assert_type(#t_bs_context{}, Ctx, Vst0),
verify_live(Live, Vst0),
verify_y_init(Vst0),
Vst = prune_x_regs(Live, Vst0),
extract_term(#t_bitstring{}, bs_get_tail, [Ctx], Dst, Vst, Vst0);
valfun_1(bs_init_writable=I, Vst) ->
call(I, 1, Vst);
valfun_1(build_stacktrace=I, Vst) ->
call(I, 1, Vst);
valfun_1({move,Src,Dst}, Vst) ->
assign(Src, Dst, Vst);
valfun_1({swap,RegA,RegB}, Vst0) ->
assert_movable(RegA, Vst0),
assert_movable(RegB, Vst0),
%% We don't expect fragile registers to be swapped.
%% Therefore, we can conservatively make both registers
%% fragile if one of the register is fragile instead of
%% swapping the fragility of the registers.
Sources = [RegA,RegB],
Vst1 = propagate_fragility(RegA, Sources, Vst0),
Vst2 = propagate_fragility(RegB, Sources, Vst1),
%% Swap the value references.
VrefA = get_reg_vref(RegA, Vst2),
VrefB = get_reg_vref(RegB, Vst2),
Vst = set_reg_vref(VrefB, RegA, Vst2),
set_reg_vref(VrefA, RegB, Vst);
valfun_1({fmove,Src,{fr,_}=Dst}, Vst) ->
assert_type(float, Src, Vst),
set_freg(Dst, Vst);
valfun_1({fmove,{fr,_}=Src,Dst}, Vst0) ->
assert_freg_set(Src, Vst0),
assert_fls(checked, Vst0),
Vst = eat_heap_float(Vst0),
create_term(float, fmove, [], Dst, Vst);
valfun_1({kill,Reg}, Vst) ->
create_tag(initialized, kill, [], Reg, Vst);
valfun_1({init,Reg}, Vst) ->
create_tag(initialized, init, [], Reg, Vst);
valfun_1({test_heap,Heap,Live}, Vst) ->
test_heap(Heap, Live, Vst);
valfun_1({bif,Op,{f,_},Ss,Dst}=I, Vst) ->
case erl_bifs:is_safe(erlang, Op, length(Ss)) of
true ->
%% It can't fail, so we finish handling it here (not updating
%% catch state).
{RetType, _, _} = bif_types(Op, Ss, Vst),
extract_term(RetType, {bif,Op}, Ss, Dst, Vst);
false ->
%% Since the BIF can fail, make sure that any catch state
%% is updated.
valfun_2(I, Vst)
end;
%% Put instructions.
valfun_1({put_list,A,B,Dst}, Vst0) ->
assert_term(A, Vst0),
assert_term(B, Vst0),
Vst = eat_heap(2, Vst0),
create_term(cons, put_list, [A, B], Dst, Vst);
valfun_1({put_tuple2,Dst,{list,Elements}}, Vst0) ->
_ = [assert_term(El, Vst0) || El <- Elements],
Size = length(Elements),
Vst = eat_heap(Size+1, Vst0),
{Es,_} = foldl(fun(Val, {Es0, Index}) ->
Type = get_term_type(Val, Vst0),
Es = beam_types:set_element_type(Index, Type, Es0),
{Es, Index + 1}
end, {#{}, 1}, Elements),
Type = #t_tuple{exact=true,size=Size,elements=Es},
create_term(Type, put_tuple2, [], Dst, Vst);
valfun_1({put_tuple,Sz,Dst}, Vst0) when is_integer(Sz) ->
Vst1 = eat_heap(1, Vst0),
Vst = create_term(#t_abstract{kind=unfinished_tuple}, put_tuple, [],
Dst, Vst1),
#vst{current=St0} = Vst,
St = St0#st{puts_left={Sz,{Dst,Sz,#{}}}},
Vst#vst{current=St};
valfun_1({put,Src}, Vst0) ->
assert_term(Src, Vst0),
Vst = eat_heap(1, Vst0),
#vst{current=St0} = Vst,
case St0 of
#st{puts_left=none} ->
error(not_building_a_tuple);
#st{puts_left={1,{Dst,Sz,Es0}}} ->
ElementType = get_term_type(Src, Vst0),
Es = beam_types:set_element_type(Sz, ElementType, Es0),
St = St0#st{puts_left=none},
Type = #t_tuple{exact=true,size=Sz,elements=Es},
create_term(Type, put_tuple, [], Dst, Vst#vst{current=St});
#st{puts_left={PutsLeft,{Dst,Sz,Es0}}} when is_integer(PutsLeft) ->
Index = Sz - PutsLeft + 1,
ElementType = get_term_type(Src, Vst0),
Es = beam_types:set_element_type(Index, ElementType, Es0),
St = St0#st{puts_left={PutsLeft-1,{Dst,Sz,Es}}},
Vst#vst{current=St}
end;
%% Instructions for optimization of selective receives.
valfun_1({recv_mark,{f,Fail}}, Vst) when is_integer(Fail) ->
Vst;
valfun_1({recv_set,{f,Fail}}, Vst) when is_integer(Fail) ->
Vst;
%% Misc.
valfun_1(remove_message, Vst) ->
%% The message term is no longer fragile. It can be used
%% without restrictions.
remove_fragility(Vst);
valfun_1({'%', {type_info, Reg, #t_bs_context{}=Type}}, Vst) ->
%% This is a gross hack, but we'll be rid of it once we have proper union
%% types.
override_type(Type, Reg, Vst);
valfun_1({'%', {type_info, Reg, Type}}, Vst) ->
%% Explicit type information inserted by optimization passes to indicate
%% that Reg has a certain type, so that we can accept cross-function type
%% optimizations.
update_type(fun meet/2, Type, Reg, Vst);
valfun_1({'%', {remove_fragility, Reg}}, Vst) ->
%% This is a hack to make prim_eval:'receive'/2 work.
%%
%% Normally it's illegal to pass fragile terms as a function argument as we
%% have no way of knowing what the callee will do with it, but we know that
%% prim_eval:'receive'/2 won't leak the term, nor cause a GC since it's
%% disabled while matching messages.
remove_fragility(Reg, Vst);
valfun_1({'%',_}, Vst) ->
Vst;
valfun_1({line,_}, Vst) ->
Vst;
%% Exception generating calls
valfun_1({call_ext,Live,Func}=I, Vst) ->
case call_types(Func, Live, Vst) of
{none, _, _} ->
verify_live(Live, Vst),
%% The stack will be scanned, so Y registers
%% must be initialized.
verify_y_init(Vst),
kill_state(Vst);
_ ->
valfun_2(I, Vst)
end;
valfun_1(_I, #vst{current=#st{ct=undecided}}) ->
error(unknown_catch_try_state);
%%
%% Allocate and deallocate, et.al
valfun_1({allocate,Stk,Live}, Vst) ->
allocate(uninitialized, Stk, 0, Live, Vst);
valfun_1({allocate_heap,Stk,Heap,Live}, Vst) ->
allocate(uninitialized, Stk, Heap, Live, Vst);
valfun_1({allocate_zero,Stk,Live}, Vst) ->
allocate(initialized, Stk, 0, Live, Vst);
valfun_1({allocate_heap_zero,Stk,Heap,Live}, Vst) ->
allocate(initialized, Stk, Heap, Live, Vst);
valfun_1({deallocate,StkSize}, #vst{current=#st{numy=StkSize}}=Vst) ->
verify_no_ct(Vst),
deallocate(Vst);
valfun_1({deallocate,_}, #vst{current=#st{numy=NumY}}) ->
error({allocated,NumY});
valfun_1({trim,N,Remaining}, #vst{current=St0}=Vst) ->
#st{numy=NumY} = St0,
if
N =< NumY, N+Remaining =:= NumY ->
Vst#vst{current=trim_stack(N, 0, NumY, St0)};
N > NumY; N+Remaining =/= NumY ->
error({trim,N,Remaining,allocated,NumY})
end;
%% Catch & try.
valfun_1({'catch',Dst,{f,Fail}}, Vst) when Fail =/= none ->
init_try_catch_branch(catchtag, Dst, Fail, Vst);
valfun_1({'try',Dst,{f,Fail}}, Vst) when Fail =/= none ->
init_try_catch_branch(trytag, Dst, Fail, Vst);
valfun_1({catch_end,Reg}, #vst{current=#st{ct=[Fail|_]}}=Vst0) ->
case get_tag_type(Reg, Vst0) of
{catchtag,Fail} ->
%% {x,0} contains the caught term, if any.
create_term(any, catch_end, [], {x,0}, kill_catch_tag(Reg, Vst0));
Type ->
error({wrong_tag_type,Type})
end;
valfun_1({try_end,Reg}, #vst{current=#st{ct=[Fail|_]}}=Vst) ->
case get_tag_type(Reg, Vst) of
{trytag,Fail} ->
%% Kill the catch tag, note that x registers are unaffected.
kill_catch_tag(Reg, Vst);
Type ->
error({wrong_tag_type,Type})
end;
valfun_1({try_case,Reg}, #vst{current=#st{ct=[Fail|_]}}=Vst0) ->
case get_tag_type(Reg, Vst0) of
{trytag,Fail} ->
%% Kill the catch tag and all x registers.
Vst1 = prune_x_regs(0, kill_catch_tag(Reg, Vst0)),
%% Class:Error:Stacktrace
Vst2 = create_term(#t_atom{}, try_case, [], {x,0}, Vst1),
Vst = create_term(any, try_case, [], {x,1}, Vst2),
create_term(any, try_case, [], {x,2}, Vst);
Type ->
error({wrong_tag_type,Type})
end;
valfun_1({get_list,Src,D1,D2}, Vst0) ->
assert_not_literal(Src),
assert_type(cons, Src, Vst0),
Vst = extract_term(any, get_hd, [Src], D1, Vst0),
extract_term(any, get_tl, [Src], D2, Vst);
valfun_1({get_hd,Src,Dst}, Vst) ->
assert_not_literal(Src),
assert_type(cons, Src, Vst),
extract_term(any, get_hd, [Src], Dst, Vst);
valfun_1({get_tl,Src,Dst}, Vst) ->
assert_not_literal(Src),
assert_type(cons, Src, Vst),
extract_term(any, get_tl, [Src], Dst, Vst);
valfun_1({get_tuple_element,Src,N,Dst}, Vst) ->
Index = N+1,
assert_not_literal(Src),
assert_type(#t_tuple{size=Index}, Src, Vst),
#t_tuple{elements=Es} = normalize(get_term_type(Src, Vst)),
Type = beam_types:get_element_type(Index, Es),
extract_term(Type, {bif,element}, [{integer,Index}, Src], Dst, Vst);
valfun_1({jump,{f,Lbl}}, Vst) ->
branch(Lbl, Vst,
fun(SuccVst) ->
%% The next instruction is never executed.
kill_state(SuccVst)
end);
valfun_1(I, Vst) ->
valfun_2(I, Vst).
init_try_catch_branch(Tag, Dst, Fail, Vst0) ->
Vst1 = create_tag({Tag,[Fail]}, 'try_catch', [], Dst, Vst0),
#vst{current=#st{ct=Fails}=St0} = Vst1,
St = St0#st{ct=[[Fail]|Fails]},
Vst = Vst0#vst{current=St},
branch(Fail, Vst,
fun(CatchVst) ->
#vst{current=#st{ys=Ys}} = CatchVst,
maps:fold(fun init_catch_handler_1/3, CatchVst, Ys)
end,
fun(SuccVst) ->
%% All potentially-throwing instructions after this
%% one will implicitly branch to the fail label;
%% see valfun_2/2
SuccVst
end).
%% Set the initial state at the try/catch label. Assume that Y registers
%% contain terms or try/catch tags.
init_catch_handler_1(Reg, initialized, Vst) ->
create_term(any, 'catch_handler', [], Reg, Vst);
init_catch_handler_1(Reg, uninitialized, Vst) ->
create_term(any, 'catch_handler', [], Reg, Vst);
init_catch_handler_1(_, _, Vst) ->
Vst.
valfun_2(I, #vst{current=#st{ct=[[Fail]|_]}}=Vst) when is_integer(Fail) ->
%% We have an active try/catch tag and we can jump there from this
%% instruction, so we need to update the branched state of the try/catch
%% handler.
valfun_3(I, branch_state(Fail, Vst));
valfun_2(I, #vst{current=#st{ct=[]}}=Vst) ->
valfun_3(I, Vst);
valfun_2(_, _) ->
error(ambiguous_catch_try_state).
%% Handle the remaining floating point instructions here.
%% Floating point.
valfun_3({fconv,Src,{fr,_}=Dst}, Vst) ->
assert_term(Src, Vst),
%% An exception is raised on error, hence branching to 0.
branch(0, Vst,
fun(SuccVst0) ->
SuccVst = update_type(fun meet/2, number, Src, SuccVst0),
set_freg(Dst, SuccVst)
end);
valfun_3({bif,fadd,_,[_,_]=Ss,Dst}, Vst) ->
float_op(Ss, Dst, Vst);
valfun_3({bif,fdiv,_,[_,_]=Ss,Dst}, Vst) ->
float_op(Ss, Dst, Vst);
valfun_3({bif,fmul,_,[_,_]=Ss,Dst}, Vst) ->
float_op(Ss, Dst, Vst);
valfun_3({bif,fnegate,_,[_]=Ss,Dst}, Vst) ->
float_op(Ss, Dst, Vst);
valfun_3({bif,fsub,_,[_,_]=Ss,Dst}, Vst) ->
float_op(Ss, Dst, Vst);
valfun_3(fclearerror, Vst) ->
case get_fls(Vst) of
undefined -> ok;
checked -> ok;
Fls -> error({bad_floating_point_state,Fls})
end,
set_fls(cleared, Vst);
valfun_3({fcheckerror,_}, Vst) ->
assert_fls(cleared, Vst),
set_fls(checked, Vst);
valfun_3(I, Vst) ->
%% The instruction is not a float instruction.
case get_fls(Vst) of
undefined ->
valfun_4(I, Vst);
checked ->
valfun_4(I, Vst);
Fls ->
error({unsafe_instruction,{float_error_state,Fls}})
end.
%% Instructions that can cause exceptions.
valfun_4({apply,Live}, Vst) ->
call(apply, Live+2, Vst);
valfun_4({apply_last,Live,_}, Vst) ->
tail_call(apply, Live+2, Vst);
valfun_4({call_fun,Live}, Vst) ->
Fun = {x,Live},
assert_term(Fun, Vst),
%% An exception is raised on error, hence branching to 0.
branch(0, Vst,
fun(SuccVst0) ->
SuccVst = update_type(fun meet/2, #t_fun{arity=Live},
Fun, SuccVst0),
call('fun', Live+1, SuccVst)
end);
valfun_4({call,Live,Func}, Vst) ->
call(Func, Live, Vst);
valfun_4({call_ext,Live,Func}, Vst) ->
%% Exception BIFs has already been taken care of above.
call(Func, Live, Vst);
valfun_4({call_only,Live,Func}, Vst) ->
tail_call(Func, Live, Vst);
valfun_4({call_ext_only,Live,Func}, Vst) ->
tail_call(Func, Live, Vst);
valfun_4({call_last,Live,Func,StkSize}, #vst{current=#st{numy=StkSize}}=Vst) ->
tail_call(Func, Live, Vst);
valfun_4({call_last,_,_,_}, #vst{current=#st{numy=NumY}}) ->
error({allocated,NumY});
valfun_4({call_ext_last,Live,Func,StkSize},
#vst{current=#st{numy=StkSize}}=Vst) ->
tail_call(Func, Live, Vst);
valfun_4({call_ext_last,_,_,_}, #vst{current=#st{numy=NumY}}) ->
error({allocated,NumY});
valfun_4({make_fun2,{f,Lbl},_,_,NumFree}, #vst{ft=Ft}=Vst0) ->
#{ arity := Arity0 } = gb_trees:get(Lbl, Ft),
Arity = Arity0 - NumFree,
true = Arity >= 0, %Assertion.
Vst = prune_x_regs(NumFree, Vst0),
verify_call_args(make_fun, NumFree, Vst),
verify_y_init(Vst),
create_term(#t_fun{arity=Arity}, make_fun, [], {x,0}, Vst);
%% Other BIFs
valfun_4({bif,raise,{f,0},Src,_Dst}, Vst) ->
validate_src(Src, Vst),
kill_state(Vst);
valfun_4(raw_raise=I, Vst) ->
call(I, 3, Vst);
valfun_4({bif,Op,{f,Fail},Ss,Dst}, Vst) ->
validate_src(Ss, Vst),
validate_bif(bif, Op, Fail, Ss, Dst, Vst, Vst);
valfun_4({gc_bif,Op,{f,Fail},Live,Ss,Dst}, #vst{current=St0}=Vst0) ->
validate_src(Ss, Vst0),
verify_live(Live, Vst0),
verify_y_init(Vst0),
%% Heap allocations and X registers are killed regardless of whether we
%% fail or not, as we may fail after GC.
St = kill_heap_allocation(St0),
Vst = prune_x_regs(Live, Vst0#vst{current=St}),
validate_bif(gc_bif, Op, Fail, Ss, Dst, Vst0, Vst);
valfun_4(return, #vst{current=#st{numy=none}}=Vst) ->
assert_durable_term({x,0}, Vst),
kill_state(Vst);
valfun_4(return, #vst{current=#st{numy=NumY}}) ->
error({stack_frame,NumY});
valfun_4({loop_rec,{f,Fail},Dst}, Vst) ->
%% This term may not be part of the root set until remove_message/0 is
%% executed. If control transfers to the loop_rec_end/1 instruction, no
%% part of this term must be stored in a Y register.
branch(Fail, Vst,
fun(SuccVst0) ->
{Ref, SuccVst} = new_value(any, loop_rec, [], SuccVst0),
mark_fragile(Dst, set_reg_vref(Ref, Dst, SuccVst))
end);
valfun_4({wait,_}, Vst) ->
verify_y_init(Vst),
kill_state(Vst);
valfun_4({wait_timeout,_,Src}, Vst) ->
assert_term(Src, Vst),
verify_y_init(Vst),
prune_x_regs(0, Vst);
valfun_4({loop_rec_end,_}, Vst) ->
verify_y_init(Vst),
kill_state(Vst);
valfun_4(timeout, Vst) ->
prune_x_regs(0, Vst);
valfun_4(send, Vst) ->
call(send, 2, Vst);
valfun_4({set_tuple_element,Src,Tuple,N}, Vst) ->
I = N + 1,
assert_term(Src, Vst),
assert_type(#t_tuple{size=I}, Tuple, Vst),
%% Manually update the tuple type; we can't rely on the ordinary update
%% helpers as we must support overwriting (rather than just widening or
%% narrowing) known elements, and we can't use extract_term either since
%% the source tuple may be aliased.
#t_tuple{elements=Es0}=Type = normalize(get_term_type(Tuple, Vst)),
Es = beam_types:set_element_type(I, get_term_type(Src, Vst), Es0),
override_type(Type#t_tuple{elements=Es}, Tuple, Vst);
%% Match instructions.
valfun_4({select_val,Src,{f,Fail},{list,Choices}}, Vst) ->
assert_term(Src, Vst),
assert_choices(Choices),
validate_select_val(Fail, Choices, Src, Vst);
valfun_4({select_tuple_arity,Tuple,{f,Fail},{list,Choices}}, Vst) ->
assert_type(#t_tuple{}, Tuple, Vst),
assert_arities(Choices),
validate_select_tuple_arity(Fail, Choices, Tuple, Vst);
%% New bit syntax matching instructions.
valfun_4({test,bs_start_match3,{f,Fail},Live,[Src],Dst}, Vst) ->
validate_bs_start_match(Fail, Live, bsm_match_state(), Src, Dst, Vst);
valfun_4({test,bs_start_match2,{f,Fail},Live,[Src,Slots],Dst}, Vst) ->
validate_bs_start_match(Fail, Live, bsm_match_state(Slots), Src, Dst, Vst);
valfun_4({test,bs_match_string,{f,Fail},[Ctx,_,_]}, Vst) ->
assert_type(#t_bs_context{}, Ctx, Vst),
branch(Fail, Vst, fun(V) -> V end);
valfun_4({test,bs_skip_bits2,{f,Fail},[Ctx,Src,_,_]}, Vst) ->
assert_type(#t_bs_context{}, Ctx, Vst),
assert_term(Src, Vst),
branch(Fail, Vst, fun(V) -> V end);
valfun_4({test,bs_test_tail2,{f,Fail},[Ctx,_]}, Vst) ->
assert_type(#t_bs_context{}, Ctx, Vst),
branch(Fail, Vst, fun(V) -> V end);
valfun_4({test,bs_test_unit,{f,Fail},[Ctx,_]}, Vst) ->
assert_type(#t_bs_context{}, Ctx, Vst),
branch(Fail, Vst, fun(V) -> V end);
valfun_4({test,bs_skip_utf8,{f,Fail},[Ctx,Live,_]}, Vst) ->
validate_bs_skip_utf(Fail, Ctx, Live, Vst);
valfun_4({test,bs_skip_utf16,{f,Fail},[Ctx,Live,_]}, Vst) ->
validate_bs_skip_utf(Fail, Ctx, Live, Vst);
valfun_4({test,bs_skip_utf32,{f,Fail},[Ctx,Live,_]}, Vst) ->
validate_bs_skip_utf(Fail, Ctx, Live, Vst);
valfun_4({test,bs_get_integer2=Op,{f,Fail},Live,
[Ctx,{integer,Size},Unit,{field_flags,Flags}],Dst},Vst)
when Size * Unit =< 64 ->
Type = case member(unsigned, Flags) of
true ->
NumBits = Size * Unit,
beam_types:make_integer(0, (1 bsl NumBits)-1);
false ->
%% Signed integer or way too large, don't bother.
#t_integer{}
end,
validate_bs_get(Op, Fail, Ctx, Live, Type, Dst, Vst);
valfun_4({test,bs_get_integer2=Op,{f,Fail},Live,
[Ctx,_Size,_Unit,_Flags],Dst},Vst) ->
validate_bs_get(Op, Fail, Ctx, Live, #t_integer{}, Dst, Vst);
valfun_4({test,bs_get_float2=Op,{f,Fail},Live,[Ctx,_,_,_],Dst}, Vst) ->
validate_bs_get(Op, Fail, Ctx, Live, float, Dst, Vst);
valfun_4({test,bs_get_binary2=Op,{f,Fail},Live,[Ctx,_,Unit,_],Dst}, Vst) ->
validate_bs_get(Op, Fail, Ctx, Live, #t_bitstring{unit=Unit}, Dst, Vst);
valfun_4({test,bs_get_utf8=Op,{f,Fail},Live,[Ctx,_],Dst}, Vst) ->
Type = beam_types:make_integer(0, ?UNICODE_MAX),
validate_bs_get(Op, Fail, Ctx, Live, Type, Dst, Vst);
valfun_4({test,bs_get_utf16=Op,{f,Fail},Live,[Ctx,_],Dst}, Vst) ->
Type = beam_types:make_integer(0, ?UNICODE_MAX),
validate_bs_get(Op, Fail, Ctx, Live, Type, Dst, Vst);
valfun_4({test,bs_get_utf32=Op,{f,Fail},Live,[Ctx,_],Dst}, Vst) ->
Type = beam_types:make_integer(0, ?UNICODE_MAX),
validate_bs_get(Op, Fail, Ctx, Live, Type, Dst, Vst);
valfun_4({bs_save2,Ctx,SavePoint}, Vst) ->
bsm_save(Ctx, SavePoint, Vst);
valfun_4({bs_restore2,Ctx,SavePoint}, Vst) ->
bsm_restore(Ctx, SavePoint, Vst);
valfun_4({bs_get_position, Ctx, Dst, Live}, Vst0) ->
assert_type(#t_bs_context{}, Ctx, Vst0),
verify_live(Live, Vst0),
verify_y_init(Vst0),
Vst = prune_x_regs(Live, Vst0),
create_term(#t_abstract{kind=ms_position}, bs_get_position, [Ctx],
Dst, Vst, Vst0);
valfun_4({bs_set_position, Ctx, Pos}, Vst) ->
assert_type(#t_bs_context{}, Ctx, Vst),
assert_type(#t_abstract{kind=ms_position}, Pos, Vst),
Vst;
%% Other test instructions.
valfun_4({test,has_map_fields,{f,Lbl},Src,{list,List}}, Vst) ->
assert_type(#t_map{}, Src, Vst),
assert_unique_map_keys(List),
branch(Lbl, Vst, fun(V) -> V end);
valfun_4({test,is_atom,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, #t_atom{}, Src, Vst);
valfun_4({test,is_binary,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, #t_bitstring{unit=8}, Src, Vst);
valfun_4({test,is_bitstr,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, #t_bitstring{}, Src, Vst);
valfun_4({test,is_boolean,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, beam_types:make_boolean(), Src, Vst);
valfun_4({test,is_float,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, float, Src, Vst);
valfun_4({test,is_tuple,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, #t_tuple{}, Src, Vst);
valfun_4({test,is_integer,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, #t_integer{}, Src, Vst);
valfun_4({test,is_nonempty_list,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, cons, Src, Vst);
valfun_4({test,is_number,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, number, Src, Vst);
valfun_4({test,is_list,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, list, Src, Vst);
valfun_4({test,is_map,{f,Lbl},[Src]}, Vst) ->
type_test(Lbl, #t_map{}, Src, Vst);
valfun_4({test,is_nil,{f,Lbl},[Src]}, Vst) ->
%% is_nil is an exact check against the 'nil' value, and should not be
%% treated as a simple type test.
assert_term(Src, Vst),
branch(Lbl, Vst,
fun(FailVst) ->
update_ne_types(Src, nil, FailVst)
end,
fun(SuccVst) ->
update_eq_types(Src, nil, SuccVst)
end);
valfun_4({test,test_arity,{f,Lbl},[Tuple,Sz]}, Vst) when is_integer(Sz) ->
assert_type(#t_tuple{}, Tuple, Vst),
Type = #t_tuple{exact=true,size=Sz},
type_test(Lbl, Type, Tuple, Vst);
valfun_4({test,is_tagged_tuple,{f,Lbl},[Src,Sz,Atom]}, Vst) ->
assert_term(Src, Vst),
Es = #{ 1 => get_literal_type(Atom) },
Type = #t_tuple{exact=true,size=Sz,elements=Es},
type_test(Lbl, Type, Src, Vst);
valfun_4({test,is_eq_exact,{f,Lbl},[Src,Val]=Ss}, Vst) ->
validate_src(Ss, Vst),
branch(Lbl, Vst,
fun(FailVst) ->
update_ne_types(Src, Val, FailVst)
end,
fun(SuccVst) ->
update_eq_types(Src, Val, SuccVst)
end);
valfun_4({test,is_ne_exact,{f,Lbl},[Src,Val]=Ss}, Vst) ->
validate_src(Ss, Vst),
branch(Lbl, Vst,
fun(FailVst) ->
update_eq_types(Src, Val, FailVst)
end,
fun(SuccVst) ->
update_ne_types(Src, Val, SuccVst)
end);
valfun_4({test,_Op,{f,Lbl},Src}, Vst) ->
%% is_pid, is_reference, et cetera.
validate_src(Src, Vst),
branch(Lbl, Vst, fun(V) -> V end);
valfun_4({bs_add,{f,Fail},[A,B,_],Dst}, Vst) ->
assert_term(A, Vst),
assert_term(B, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
create_term(#t_integer{}, bs_add, [A, B], Dst, SuccVst)
end);
valfun_4({bs_utf8_size,{f,Fail},A,Dst}, Vst) ->
assert_term(A, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
create_term(#t_integer{}, bs_utf8_size, [A], Dst, SuccVst)
end);
valfun_4({bs_utf16_size,{f,Fail},A,Dst}, Vst) ->
assert_term(A, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
create_term(#t_integer{}, bs_utf16_size, [A], Dst, SuccVst)
end);
valfun_4({bs_init2,{f,Fail},Sz,Heap,Live,_,Dst}, Vst0) ->
verify_live(Live, Vst0),
verify_y_init(Vst0),
if
is_integer(Sz) ->
ok;
true ->
assert_term(Sz, Vst0)
end,
Vst = heap_alloc(Heap, Vst0),
branch(Fail, Vst,
fun(SuccVst0) ->
SuccVst = prune_x_regs(Live, SuccVst0),
create_term(#t_bitstring{unit=8}, bs_init2, [], Dst,
SuccVst, SuccVst0)
end);
valfun_4({bs_init_bits,{f,Fail},Sz,Heap,Live,_,Dst}, Vst0) ->
verify_live(Live, Vst0),
verify_y_init(Vst0),
if
is_integer(Sz) ->
ok;
true ->
assert_term(Sz, Vst0)
end,
Vst = heap_alloc(Heap, Vst0),
branch(Fail, Vst,
fun(SuccVst0) ->
SuccVst = prune_x_regs(Live, SuccVst0),
create_term(#t_bitstring{}, bs_init_bits, [], Dst, SuccVst)
end);
valfun_4({bs_append,{f,Fail},Bits,Heap,Live,Unit,Bin,_Flags,Dst}, Vst0) ->
verify_live(Live, Vst0),
verify_y_init(Vst0),
assert_term(Bits, Vst0),
assert_term(Bin, Vst0),
Vst = heap_alloc(Heap, Vst0),
branch(Fail, Vst,
fun(SuccVst0) ->
SuccVst = prune_x_regs(Live, SuccVst0),
create_term(#t_bitstring{unit=Unit}, bs_append,
[Bin], Dst, SuccVst, SuccVst0)
end);
valfun_4({bs_private_append,{f,Fail},Bits,Unit,Bin,_Flags,Dst}, Vst) ->
assert_term(Bits, Vst),
assert_term(Bin, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
create_term(#t_bitstring{unit=Unit}, bs_private_append,
[Bin], Dst, SuccVst)
end);
valfun_4({bs_put_string,Sz,_}, Vst) when is_integer(Sz) ->
Vst;
valfun_4({bs_put_binary,{f,Fail},Sz,_,_,Src}, Vst) ->
assert_term(Sz, Vst),
assert_term(Src, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
update_type(fun meet/2, #t_bitstring{}, Src, SuccVst)
end);
valfun_4({bs_put_float,{f,Fail},Sz,_,_,Src}, Vst) ->
assert_term(Sz, Vst),
assert_term(Src, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
update_type(fun meet/2, float, Src, SuccVst)
end);
valfun_4({bs_put_integer,{f,Fail},Sz,_,_,Src}, Vst) ->
assert_term(Sz, Vst),
assert_term(Src, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
update_type(fun meet/2, #t_integer{}, Src, SuccVst)
end);
valfun_4({bs_put_utf8,{f,Fail},_,Src}, Vst) ->
assert_term(Src, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
update_type(fun meet/2, #t_integer{}, Src, SuccVst)
end);
valfun_4({bs_put_utf16,{f,Fail},_,Src}, Vst) ->
assert_term(Src, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
update_type(fun meet/2, #t_integer{}, Src, SuccVst)
end);
valfun_4({bs_put_utf32,{f,Fail},_,Src}, Vst) ->
assert_term(Src, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
update_type(fun meet/2, #t_integer{}, Src, SuccVst)
end);
%% Map instructions.
valfun_4({put_map_assoc=Op,{f,Fail},Src,Dst,Live,{list,List}}, Vst) ->
verify_put_map(Op, Fail, Src, Dst, Live, List, Vst);
valfun_4({put_map_exact=Op,{f,Fail},Src,Dst,Live,{list,List}}, Vst) ->
verify_put_map(Op, Fail, Src, Dst, Live, List, Vst);
valfun_4({get_map_elements,{f,Fail},Src,{list,List}}, Vst) ->
verify_get_map(Fail, Src, List, Vst);
valfun_4(_, _) ->
error(unknown_instruction).
verify_get_map(Fail, Src, List, Vst0) ->
assert_not_literal(Src), %OTP 22.
assert_type(#t_map{}, Src, Vst0),
branch(Fail, Vst0,
fun(FailVst) ->
clobber_map_vals(List, Src, FailVst)
end,
fun(SuccVst) ->
Keys = extract_map_keys(List),
assert_unique_map_keys(Keys),
extract_map_vals(List, Src, SuccVst, SuccVst)
end).
%% get_map_elements may leave its destinations in an inconsistent state when
%% the fail label is taken. Consider the following:
%%
%% {get_map_elements,{f,7},{x,1},{list,[{atom,a},{x,1},{atom,b},{x,2}]}}.
%%
%% If 'a' exists but not 'b', {x,1} is overwritten when we jump to {f,7}.
clobber_map_vals([Key,Dst|T], Map, Vst0) ->
case is_reg_defined(Dst, Vst0) of
true ->
Vst = extract_term(any, {bif,map_get}, [Key, Map], Dst, Vst0),
clobber_map_vals(T, Map, Vst);
false ->
clobber_map_vals(T, Map, Vst0)
end;
clobber_map_vals([], _Map, Vst) ->
Vst.
extract_map_keys([Key,_Val|T]) ->
[Key|extract_map_keys(T)];
extract_map_keys([]) -> [].
extract_map_vals([Key,Dst|Vs], Map, Vst0, Vsti0) ->
assert_term(Key, Vst0),
Vsti = extract_term(any, {bif,map_get}, [Key, Map], Dst, Vsti0),
extract_map_vals(Vs, Map, Vst0, Vsti);
extract_map_vals([], _Map, _Vst0, Vst) ->
Vst.
verify_put_map(Op, Fail, Src, Dst, Live, List, Vst0) ->
assert_type(#t_map{}, Src, Vst0),
verify_live(Live, Vst0),
verify_y_init(Vst0),
_ = [assert_term(Term, Vst0) || Term <- List],
Vst = heap_alloc(0, Vst0),
branch(Fail, Vst,
fun(SuccVst0) ->
SuccVst = prune_x_regs(Live, SuccVst0),
Keys = extract_map_keys(List),
assert_unique_map_keys(Keys),
create_term(#t_map{}, Op, [Src], Dst, SuccVst, SuccVst0)
end).
%%
%% Common code for validating BIFs.
%%
%% OrigVst is the state we entered the instruction with, which is needed for
%% gc_bifs as X registers are pruned prior to calling this function, which may
%% have clobbered the sources.
%%
validate_bif(Kind, Op, Fail, Ss, Dst, OrigVst, Vst) ->
{Type, ArgTypes, CanSubtract} = bif_types(Op, Ss, Vst),
ZippedArgs = zip(Ss, ArgTypes),
FailFun = case CanSubtract of
true ->
fun(FailVst0) ->
foldl(fun({A, T}, V) ->
update_type(fun subtract/2, T, A, V)
end, FailVst0, ZippedArgs)
end;
false ->
fun(S) -> S end
end,
SuccFun = fun(SuccVst0) ->
SuccVst = foldl(fun({A, T}, V) ->
update_type(fun meet/2, T, A, V)
end, SuccVst0, ZippedArgs),
extract_term(Type, {Kind,Op}, Ss, Dst, SuccVst, OrigVst)
end,
branch(Fail, Vst, FailFun, SuccFun).
%%
%% Common code for validating bs_start_match* instructions.
%%
validate_bs_start_match(Fail, Live, Type, Src, Dst, Vst) ->
verify_live(Live, Vst),
verify_y_init(Vst),
%% #t_bs_context{} can represent either a match context or a term, so we
%% have to mark the source as a term if it fails with a match context as an
%% input. This hack is only needed until we get proper union types.
branch(Fail, Vst,
fun(FailVst) ->
case get_movable_term_type(Src, FailVst) of
#t_bs_context{} -> override_type(any, Src, FailVst);
_ -> FailVst
end
end,
fun(SuccVst0) ->
SuccVst1 = update_type(fun meet/2, #t_bitstring{},
Src, SuccVst0),
SuccVst = prune_x_regs(Live, SuccVst1),
extract_term(Type, bs_start_match, [Src], Dst,
SuccVst, SuccVst0)
end).
%%
%% Common code for validating bs_get* instructions.
%%
validate_bs_get(Op, Fail, Ctx, Live, Type, Dst, Vst) ->
assert_type(#t_bs_context{}, Ctx, Vst),
verify_live(Live, Vst),
verify_y_init(Vst),
branch(Fail, Vst,
fun(SuccVst0) ->
SuccVst = prune_x_regs(Live, SuccVst0),
extract_term(Type, Op, [Ctx], Dst, SuccVst, SuccVst0)
end).
%%
%% Common code for validating bs_skip_utf* instructions.
%%
validate_bs_skip_utf(Fail, Ctx, Live, Vst) ->
assert_type(#t_bs_context{}, Ctx, Vst),
verify_y_init(Vst),
verify_live(Live, Vst),
branch(Fail, Vst,
fun(SuccVst) ->
prune_x_regs(Live, SuccVst)
end).
%%
%% Common code for is_$type instructions.
%%
type_test(Fail, Type, Reg, Vst) ->
assert_term(Reg, Vst),
branch(Fail, Vst,
fun(FailVst) ->
update_type(fun subtract/2, Type, Reg, FailVst)
end,
fun(SuccVst) ->
update_type(fun meet/2, Type, Reg, SuccVst)
end).
%%
%% Special state handling for setelement/3 and set_tuple_element/3 instructions.
%% A possibility for garbage collection must not occur between setelement/3 and
%% set_tuple_element/3.
%%
%% Note that #vst.current will be 'none' if the instruction is unreachable.
%%
val_dsetel({move,_,_}, Vst) ->
Vst;
val_dsetel({call_ext,3,{extfunc,erlang,setelement,3}}, #vst{current=#st{}=St}=Vst) ->
Vst#vst{current=St#st{setelem=true}};
val_dsetel({set_tuple_element,_,_,_}, #vst{current=#st{setelem=false}}) ->
error(illegal_context_for_set_tuple_element);
val_dsetel({set_tuple_element,_,_,_}, #vst{current=#st{setelem=true}}=Vst) ->
Vst;
val_dsetel({get_tuple_element,_,_,_}, Vst) ->
Vst;
val_dsetel({line,_}, Vst) ->
Vst;
val_dsetel(_, #vst{current=#st{setelem=true}=St}=Vst) ->
Vst#vst{current=St#st{setelem=false}};
val_dsetel(_, Vst) -> Vst.
kill_state(Vst) ->
Vst#vst{current=none}.
%% A "plain" call.
%% The stackframe must be initialized.
%% The instruction will return to the instruction following the call.
call(Name, Live, #vst{current=St0}=Vst0) ->
verify_call_args(Name, Live, Vst0),
verify_y_init(Vst0),
case call_types(Name, Live, Vst0) of
{RetType, _, _} ->
%% Type is never 'none' because it has been handled earlier.
St = St0#st{f=init_fregs()},
Vst = prune_x_regs(0, Vst0#vst{current=St}),
create_term(RetType, call, [], {x,0}, Vst)
end.
%% Tail call.
%% The stackframe must have a known size and be initialized.
%% Does not return to the instruction following the call.
tail_call(Name, Live, Vst0) ->
verify_y_init(Vst0),
Vst = deallocate(Vst0),
verify_call_args(Name, Live, Vst),
verify_no_ct(Vst),
kill_state(Vst).
verify_call_args(_, 0, #vst{}) ->
ok;
verify_call_args({f,Lbl}, Live, #vst{ft=Ft}=Vst) when is_integer(Live) ->
case gb_trees:lookup(Lbl, Ft) of
{value, FuncInfo} ->
#{ arity := Live,
parameter_types := ParamTypes } = FuncInfo,
verify_local_args(Live - 1, ParamTypes, #{}, Vst);
none ->
error(local_call_to_unknown_function)
end;
verify_call_args(_, Live, Vst) when is_integer(Live)->
verify_remote_args_1(Live - 1, Vst);
verify_call_args(_, Live, _) ->
error({bad_number_of_live_regs,Live}).
verify_remote_args_1(-1, _) ->
ok;
verify_remote_args_1(X, Vst) ->
assert_durable_term({x, X}, Vst),
verify_remote_args_1(X - 1, Vst).
verify_local_args(-1, _ParamTypes, _CtxIds, _Vst) ->
ok;
verify_local_args(X, ParamTypes, CtxRefs, Vst) ->
Reg = {x, X},
assert_not_fragile(Reg, Vst),
case get_movable_term_type(Reg, Vst) of
#t_bs_context{}=Type ->
VRef = get_reg_vref(Reg, Vst),
case CtxRefs of
#{ VRef := Other } ->
error({multiple_match_contexts, [Reg, Other]});
#{} ->
verify_arg_type(Reg, Type, ParamTypes),
verify_local_args(X - 1, ParamTypes,
CtxRefs#{ VRef => Reg }, Vst)
end;
Type ->
verify_arg_type(Reg, Type, ParamTypes),
verify_local_args(X - 1, ParamTypes, CtxRefs, Vst)
end.
%% Verifies that the given argument narrows to what the function expects.
verify_arg_type(Reg, #t_bs_context{}, ParamTypes) ->
%% Match contexts require explicit support, and may not be passed to a
%% function that accepts arbitrary terms.
case ParamTypes of
#{ Reg := #t_bs_context{}} -> ok;
#{} -> error(no_bs_start_match2)
end;
verify_arg_type(Reg, GivenType, ParamTypes) ->
case ParamTypes of
#{ Reg := #t_bs_context{}} ->
%% Functions that accept match contexts also accept all other
%% terms. This will change once we support union types.
ok;
#{ Reg := RequiredType } ->
case meet(GivenType, RequiredType) of
GivenType -> ok;
_ -> error({bad_arg_type, Reg, GivenType, RequiredType})
end;
#{} ->
ok
end.
allocate(Tag, Stk, Heap, Live, #vst{current=#st{numy=none}=St}=Vst0) ->
verify_live(Live, Vst0),
Vst1 = Vst0#vst{current=St#st{numy=Stk}},
Vst2 = prune_x_regs(Live, Vst1),
Vst = init_stack(Tag, Stk - 1, Vst2),
heap_alloc(Heap, Vst);
allocate(_, _, _, _, #vst{current=#st{numy=Numy}}) ->
error({existing_stack_frame,{size,Numy}}).
deallocate(#vst{current=St}=Vst) ->
Vst#vst{current=St#st{ys=#{},numy=none}}.
init_stack(_Tag, -1, Vst) ->
Vst;
init_stack(Tag, Y, Vst) ->
init_stack(Tag, Y - 1, create_tag(Tag, allocate, [], {y,Y}, Vst)).
trim_stack(From, To, Top, #st{ys=Ys0}=St) when From =:= Top ->
Ys = maps:filter(fun({y,Y}, _) -> Y < To end, Ys0),
St#st{numy=To,ys=Ys};
trim_stack(From, To, Top, St0) ->
Src = {y, From},
Dst = {y, To},
#st{ys=Ys0} = St0,
Ys = case Ys0 of
#{ Src := Ref } -> Ys0#{ Dst => Ref };
#{} -> error({invalid_shift,Src,Dst})
end,
St = St0#st{ys=Ys},
trim_stack(From + 1, To + 1, Top, St).
test_heap(Heap, Live, Vst0) ->
verify_live(Live, Vst0),
verify_y_init(Vst0),
Vst = prune_x_regs(Live, Vst0),
heap_alloc(Heap, Vst).
heap_alloc(Heap, #vst{current=St0}=Vst) ->
St1 = kill_heap_allocation(St0),
St = heap_alloc_1(Heap, St1),
Vst#vst{current=St}.
heap_alloc_1({alloc,Alloc}, St) ->
heap_alloc_2(Alloc, St);
heap_alloc_1(HeapWords, St) when is_integer(HeapWords) ->
St#st{h=HeapWords}.
heap_alloc_2([{words,HeapWords}|T], St0) ->
St = St0#st{h=HeapWords},
heap_alloc_2(T, St);
heap_alloc_2([{floats,Floats}|T], St0) ->
St = St0#st{hf=Floats},
heap_alloc_2(T, St);
heap_alloc_2([], St) -> St.
prune_x_regs(Live, #vst{current=St0}=Vst) when is_integer(Live) ->
#st{fragile=Fragile0,xs=Xs0} = St0,
Fragile = cerl_sets:filter(fun({x,X}) ->
X < Live;
({y,_}) ->
true
end, Fragile0),
Xs = maps:filter(fun({x,X}, _) ->
X < Live
end, Xs0),
St = St0#st{fragile=Fragile,xs=Xs},
Vst#vst{current=St}.
%% All choices in a select_val list must be integers, floats, or atoms.
%% All must be of the same type.
assert_choices([{Tag,_},{f,_}|T]) ->
if
Tag =:= atom; Tag =:= float; Tag =:= integer ->
assert_choices_1(T, Tag);
true ->
error(bad_select_list)
end;
assert_choices([]) -> ok.
assert_choices_1([{Tag,_},{f,_}|T], Tag) ->
assert_choices_1(T, Tag);
assert_choices_1([_,{f,_}|_], _Tag) ->
error(bad_select_list);
assert_choices_1([], _Tag) -> ok.
assert_arities([Arity,{f,_}|T]) when is_integer(Arity) ->
assert_arities(T);
assert_arities([]) -> ok;
assert_arities(_) -> error(bad_tuple_arity_list).
%%%
%%% Floating point checking.
%%%
%%% Possible values for the fls field (=floating point error state).
%%%
%%% undefined - Undefined (initial state). No float operations allowed.
%%%
%%% cleared - fclearerror/0 has been executed. Float operations
%%% are allowed (such as fadd).
%%%
%%% checked - fcheckerror/1 has been executed. It is allowed to
%%% move values out of floating point registers.
%%%
%%% The following instructions may be executed in any state:
%%%
%%% fconv Src {fr,_}
%%% fmove Src {fr,_} %% Move INTO floating point register.
%%%
float_op(Ss, Dst, Vst0) ->
_ = [assert_freg_set(S, Vst0) || S <- Ss],
assert_fls(cleared, Vst0),
Vst = set_fls(cleared, Vst0),
set_freg(Dst, Vst).
assert_fls(Fls, Vst) ->
case get_fls(Vst) of
Fls -> ok;
OtherFls -> error({bad_floating_point_state,OtherFls})
end.
set_fls(Fls, #vst{current=#st{}=St}=Vst) when is_atom(Fls) ->
Vst#vst{current=St#st{fls=Fls}}.
get_fls(#vst{current=#st{fls=Fls}}) when is_atom(Fls) -> Fls.
init_fregs() -> 0.
set_freg({fr,Fr}=Freg, #vst{current=#st{f=Fregs0}=St}=Vst) ->
check_limit(Freg),
Bit = 1 bsl Fr,
if
Fregs0 band Bit =:= 0 ->
Fregs = Fregs0 bor Bit,
Vst#vst{current=St#st{f=Fregs}};
true -> Vst
end;
set_freg(Fr, _) -> error({bad_target,Fr}).
assert_freg_set({fr,Fr}=Freg, #vst{current=#st{f=Fregs}})
when is_integer(Fr), 0 =< Fr ->
if
(Fregs bsr Fr) band 1 =:= 0 ->
error({uninitialized_reg,Freg});
true ->
ok
end;
assert_freg_set(Fr, _) -> error({bad_source,Fr}).
%%% Maps
%% A single item list may be either a list or a register.
%%
%% A list with more than item must contain unique literals.
%%
%% An empty list is not allowed.
assert_unique_map_keys([]) ->
%% There is no reason to use the get_map_elements and
%% has_map_fields instructions with empty lists.
error(empty_field_list);
assert_unique_map_keys([_]) ->
ok;
assert_unique_map_keys([_,_|_]=Ls) ->
Vs = [begin
assert_literal(L),
L
end || L <- Ls],
case length(Vs) =:= sets:size(sets:from_list(Vs)) of
true -> ok;
false -> error(keys_not_unique)
end.
%%%
%%% New binary matching instructions.
%%%
bsm_match_state() ->
#t_bs_context{}.
bsm_match_state(Slots) ->
#t_bs_context{slots=Slots}.
bsm_save(Reg, {atom,start}, Vst) ->
%% Save point refering to where the match started.
%% It is always valid. But don't forget to validate the context register.
assert_type(#t_bs_context{}, Reg, Vst),
Vst;
bsm_save(Reg, SavePoint, Vst) ->
case get_movable_term_type(Reg, Vst) of
#t_bs_context{valid=Bits,slots=Slots}=Ctxt0 when SavePoint < Slots ->
Ctx = Ctxt0#t_bs_context{valid=Bits bor (1 bsl SavePoint),
slots=Slots},
override_type(Ctx, Reg, Vst);
_ ->
error({illegal_save, SavePoint})
end.
bsm_restore(Reg, {atom,start}, Vst) ->
%% (Mostly) automatic save point refering to where the match started.
%% It is always valid. But don't forget to validate the context register.
assert_type(#t_bs_context{}, Reg, Vst),
Vst;
bsm_restore(Reg, SavePoint, Vst) ->
case get_movable_term_type(Reg, Vst) of
#t_bs_context{valid=Bits,slots=Slots} when SavePoint < Slots ->
case Bits band (1 bsl SavePoint) of
0 -> error({illegal_restore, SavePoint, not_set});
_ -> Vst
end;
_ ->
error({illegal_restore, SavePoint, range})
end.
validate_select_val(_Fail, _Choices, _Src, #vst{current=none}=Vst) ->
%% We've already branched on all of Src's possible values, so we know we
%% can't reach the fail label or any of the remaining choices.
Vst;
validate_select_val(Fail, [Val,{f,L}|T], Src, Vst0) ->
Vst = branch(L, Vst0,
fun(BranchVst) ->
update_eq_types(Src, Val, BranchVst)
end,
fun(FailVst) ->
update_ne_types(Src, Val, FailVst)
end),
validate_select_val(Fail, T, Src, Vst);
validate_select_val(Fail, [], Src, Vst) ->
branch(Fail, Vst,
fun(FailVst) ->
FailType = get_term_type(Src, FailVst),
case beam_types:get_singleton_value(FailType) of
{ok, Value} ->
%% This is the only possible value at the fail
%% label, so we can infer types as if we matched it
%% directly.
Lit = value_to_literal(Value),
update_eq_types(Src, Lit, FailVst);
error ->
FailVst
end
end,
fun(SuccVst) ->
%% The next instruction is never executed.
kill_state(SuccVst)
end).
validate_select_tuple_arity(_Fail, _Choices, _Src, #vst{current=none}=Vst) ->
%% We've already branched on all of Src's possible values, so we know we
%% can't reach the fail label or any of the remaining choices.
Vst;
validate_select_tuple_arity(Fail, [Arity,{f,L}|T], Tuple, Vst0) ->
Type = #t_tuple{exact=true,size=Arity},
Vst = branch(L, Vst0,
fun(BranchVst) ->
update_type(fun meet/2, Type, Tuple, BranchVst)
end,
fun(FailVst) ->
update_type(fun subtract/2, Type, Tuple, FailVst)
end),
validate_select_tuple_arity(Fail, T, Tuple, Vst);
validate_select_tuple_arity(Fail, [], _, #vst{}=Vst) ->
branch(Fail, Vst,
fun(SuccVst) ->
%% The next instruction is never executed.
kill_state(SuccVst)
end).
%%
%% Infers types from comparisons, looking at the expressions that produced the
%% compared values and updates their types if we've learned something new from
%% the comparison.
%%
infer_types(CompareOp, {Kind,_}=LHS, RHS, Vst) when Kind =:= x; Kind =:= y ->
infer_types(CompareOp, get_reg_vref(LHS, Vst), RHS, Vst);
infer_types(CompareOp, LHS, {Kind,_}=RHS, Vst) when Kind =:= x; Kind =:= y ->
infer_types(CompareOp, LHS, get_reg_vref(RHS, Vst), Vst);
infer_types(CompareOp, LHS, RHS, #vst{current=#st{vs=Vs}}=Vst0) ->
case Vs of
#{ LHS := LEntry, RHS := REntry } ->
Vst = infer_types_1(LEntry, RHS, CompareOp, Vst0),
infer_types_1(REntry, LHS, CompareOp, Vst);
#{ LHS := LEntry } ->
infer_types_1(LEntry, RHS, CompareOp, Vst0);
#{ RHS := REntry } ->
infer_types_1(REntry, LHS, CompareOp, Vst0);
#{} ->
Vst0
end.
infer_types_1(#value{op={bif,'=:='},args=[LHS,RHS]}, Val, Op, Vst0) ->
case Val of
{atom, Bool} when Op =:= eq_exact, Bool; Op =:= ne_exact, not Bool ->
Vst = infer_types(eq_exact, RHS, LHS, Vst0),
infer_types(eq_exact, LHS, RHS, Vst);
{atom, Bool} when Op =:= ne_exact, Bool; Op =:= eq_exact, not Bool ->
Vst = infer_types(ne_exact, RHS, LHS, Vst0),
infer_types(ne_exact, LHS, RHS, Vst);
_ ->
Vst0
end;
infer_types_1(#value{op={bif,'=/='},args=[LHS,RHS]}, Val, Op, Vst0) ->
case Val of
{atom, Bool} when Op =:= ne_exact, Bool; Op =:= eq_exact, not Bool ->
Vst = infer_types(ne_exact, RHS, LHS, Vst0),
infer_types(ne_exact, LHS, RHS, Vst);
{atom, Bool} when Op =:= eq_exact, Bool; Op =:= ne_exact, not Bool ->
Vst = infer_types(eq_exact, RHS, LHS, Vst0),
infer_types(eq_exact, LHS, RHS, Vst);
_ ->
Vst0
end;
infer_types_1(#value{op={bif,element},args=[{integer,Index},Tuple]},
Val, Op, Vst) when Index >= 1 ->
Merge = case Op of
eq_exact -> fun meet/2;
ne_exact -> fun subtract/2
end,
case is_value_alive(Tuple, Vst) of
true ->
ElementType = get_term_type(Val, Vst),
Es = beam_types:set_element_type(Index, ElementType, #{}),
Type = #t_tuple{size=Index,elements=Es},
update_type(Merge, Type, Tuple, Vst);
false ->
Vst
end;
infer_types_1(#value{op={bif,is_atom},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(#t_atom{}, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_boolean},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(beam_types:make_boolean(), Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_binary},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(#t_bitstring{unit=8}, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_bitstring},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(#t_bitstring{}, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_float},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(float, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_integer},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(#t_integer{}, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_list},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(list, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_map},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(#t_map{}, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_number},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(number, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,is_tuple},args=[Src]}, Val, Op, Vst) ->
infer_type_test_bif(#t_tuple{}, Src, Val, Op, Vst);
infer_types_1(#value{op={bif,tuple_size}, args=[Tuple]},
{integer,Arity}, Op, Vst) ->
Merge = case Op of
eq_exact -> fun meet/2;
ne_exact -> fun subtract/2
end,
case is_value_alive(Tuple, Vst) of
true ->
Type = #t_tuple{exact=true,size=Arity},
update_type(Merge, Type, Tuple, Vst);
false ->
Vst
end;
infer_types_1(_, _, _, Vst) ->
Vst.
infer_type_test_bif(Type, Src, {atom, Bool}, Op, Vst) when is_boolean(Bool) ->
case is_value_alive(Src, Vst) of
true when Op =:= eq_exact, Bool; Op =:= ne_exact, not Bool ->
update_type(fun meet/2, Type, Src, Vst);
true when Op =:= ne_exact, Bool; Op =:= eq_exact, not Bool ->
update_type(fun subtract/2, Type, Src, Vst);
false ->
Vst
end;
infer_type_test_bif(_, _, _, _, Vst) ->
Vst.
%%%
%%% Keeping track of types.
%%%
%% Assigns Src to Dst and marks them as aliasing each other.
assign({y,_}=Src, {y,_}=Dst, Vst) ->
%% The stack trimming optimization may generate a move from an initialized
%% but unassigned Y register to another Y register.
case get_raw_type(Src, Vst) of
initialized -> create_tag(initialized, init, [], Dst, Vst);
_ -> assign_1(Src, Dst, Vst)
end;
assign({Kind,_}=Src, Dst, Vst) when Kind =:= x; Kind =:= y ->
assign_1(Src, Dst, Vst);
assign(Literal, Dst, Vst) ->
Type = get_literal_type(Literal),
create_term(Type, move, [Literal], Dst, Vst).
%% Creates a special tag value that isn't a regular term, such as 'initialized'
%% or 'catchtag'
create_tag(Tag, _Op, _Ss, {y,_}=Dst, #vst{current=#st{ys=Ys0}=St0}=Vst) ->
case maps:get(Dst, Ys0, uninitialized) of
{catchtag,_}=Prev ->
error(Prev);
{trytag,_}=Prev ->
error(Prev);
_ ->
check_try_catch_tags(Tag, Dst, Vst),
Ys = Ys0#{ Dst => Tag },
St = St0#st{ys=Ys},
remove_fragility(Dst, Vst#vst{current=St})
end;
create_tag(_Tag, _Op, _Ss, Dst, _Vst) ->
error({invalid_tag_register, Dst}).
%% Wipes a special tag, leaving the register initialized but empty.
kill_tag({y,_}=Reg, #vst{current=#st{ys=Ys0}=St0}=Vst) ->
_ = get_tag_type(Reg, Vst), %Assertion.
Ys = Ys0#{ Reg => initialized },
Vst#vst{current=St0#st{ys=Ys}}.
%% Creates a completely new term with the given type.
create_term(Type, Op, Ss0, Dst, Vst0) ->
create_term(Type, Op, Ss0, Dst, Vst0, Vst0).
%% As create_term/4, but uses the incoming Vst for argument resolution in
%% case x-regs have been pruned and the sources can no longer be found.
create_term(Type, Op, Ss0, Dst, Vst0, OrigVst) ->
{Ref, Vst1} = new_value(Type, Op, resolve_args(Ss0, OrigVst), Vst0),
Vst = remove_fragility(Dst, Vst1),
set_reg_vref(Ref, Dst, Vst).
%% Extracts a term from Ss, propagating fragility.
extract_term(Type, Op, Ss0, Dst, Vst0) ->
extract_term(Type, Op, Ss0, Dst, Vst0, Vst0).
%% As extract_term/4, but uses the incoming Vst for argument resolution in
%% case x-regs have been pruned and the sources can no longer be found.
extract_term(Type, Op, Ss0, Dst, Vst0, OrigVst) ->
{Ref, Vst1} = new_value(Type, Op, resolve_args(Ss0, OrigVst), Vst0),
Vst = propagate_fragility(Dst, Ss0, Vst1),
set_reg_vref(Ref, Dst, Vst).
%% Translates instruction arguments into the argument() type, decoupling them
%% from their registers, allowing us to infer their types after they've been
%% clobbered or moved.
resolve_args([{Kind,_}=Src | Args], Vst) when Kind =:= x; Kind =:= y ->
[get_reg_vref(Src, Vst) | resolve_args(Args, Vst)];
resolve_args([Lit | Args], Vst) ->
assert_literal(Lit),
[Lit | resolve_args(Args, Vst)];
resolve_args([], _Vst) ->
[].
%% Overrides the type of Reg. This is ugly but a necessity for certain
%% destructive operations.
override_type(Type, Reg, Vst) ->
update_type(fun(_, T) -> T end, Type, Reg, Vst).
%% This is used when linear code finds out more and more information about a
%% type, so that the type gets more specialized.
update_type(Merge, With, #value_ref{}=Ref, Vst) ->
%% If the old type can't be merged with the new one, the type information
%% is inconsistent and we know that some instructions will never be
%% executed at run-time. For example:
%%
%% {test,is_list,Fail,[Reg]}.
%% {test,is_tuple,Fail,[Reg]}.
%% {test,test_arity,Fail,[Reg,5]}.
%%
%% Note that the test_arity instruction can never be reached, so we need to
%% kill the state to avoid raising an error when we encounter it.
%%
%% Simply returning `kill_state(Vst)` is unsafe however as we might be in
%% the middle of an instruction, and altering the rest of the validator
%% (eg. prune_x_regs/2) to no-op on dead states is prone to error.
%%
%% We therefore throw a 'type_conflict' error instead, which causes
%% validation to fail unless we're in a context where such errors can be
%% handled, such as in a branch handler.
Current = get_raw_type(Ref, Vst),
case Merge(Current, With) of
none -> throw({type_conflict, Current, With});
Type -> set_type(Type, Ref, Vst)
end;
update_type(Merge, With, {Kind,_}=Reg, Vst) when Kind =:= x; Kind =:= y ->
update_type(Merge, With, get_reg_vref(Reg, Vst), Vst);
update_type(Merge, With, Literal, Vst) ->
%% Literals always retain their type, but we still need to bail on type
%% conflicts.
Type = get_literal_type(Literal),
case Merge(Type, With) of
none -> throw({type_conflict, Type, With});
_Type -> Vst
end.
update_eq_types(LHS, RHS, Vst0) ->
Vst1 = infer_types(eq_exact, LHS, RHS, Vst0),
T1 = get_term_type(LHS, Vst1),
T2 = get_term_type(RHS, Vst1),
Vst = update_type(fun meet/2, T2, LHS, Vst1),
update_type(fun meet/2, T1, RHS, Vst).
update_ne_types(LHS, RHS, Vst0) ->
Vst = infer_types(ne_exact, LHS, RHS, Vst0),
%% While updating types on equality is fairly straightforward, inequality
%% is a bit trickier since all we know is that the *value* of LHS differs
%% from RHS, so we can't blindly subtract their types.
%%
%% Consider `number =/= #t_integer{}`; all we know is that LHS isn't equal
%% to some *specific integer* of unknown value, and if we were to subtract
%% #t_integer{} we would erroneously infer that the new type is float.
%%
%% Therefore, we only subtract when we know that RHS has a specific value.
RType = get_term_type(RHS, Vst),
case beam_types:is_singleton_type(RType) of
true -> update_type(fun subtract/2, RType, LHS, Vst);
false -> Vst
end.
%% Helper functions for the above.
assign_1(Src, Dst, Vst0) ->
assert_movable(Src, Vst0),
Vst = propagate_fragility(Dst, [Src], Vst0),
set_reg_vref(get_reg_vref(Src, Vst), Dst, Vst).
set_reg_vref(Ref, {x,_}=Dst, Vst) ->
check_limit(Dst),
#vst{current=#st{xs=Xs0}=St0} = Vst,
St = St0#st{xs=Xs0#{ Dst => Ref }},
Vst#vst{current=St};
set_reg_vref(Ref, {y,_}=Dst, #vst{current=#st{ys=Ys0}=St0} = Vst) ->
check_limit(Dst),
case Ys0 of
#{ Dst := {catchtag,_}=Tag } ->
error(Tag);
#{ Dst := {trytag,_}=Tag } ->
error(Tag);
#{ Dst := _ } ->
St = St0#st{ys=Ys0#{ Dst => Ref }},
Vst#vst{current=St};
#{} ->
%% Storing into a non-existent Y register means that we haven't set
%% up a (sufficiently large) stack.
error({invalid_store, Dst})
end.
get_reg_vref({x,_}=Src, #vst{current=#st{xs=Xs}}) ->
check_limit(Src),
case Xs of
#{ Src := #value_ref{}=Ref } ->
Ref;
#{} ->
error({uninitialized_reg, Src})
end;
get_reg_vref({y,_}=Src, #vst{current=#st{ys=Ys}}) ->
check_limit(Src),
case Ys of
#{ Src := #value_ref{}=Ref } ->
Ref;
#{ Src := initialized } ->
error({unassigned, Src});
#{ Src := Tag } when Tag =/= uninitialized ->
error(Tag);
#{} ->
error({uninitialized_reg, Src})
end.
set_type(Type, #value_ref{}=Ref, #vst{current=#st{vs=Vs0}=St}=Vst) ->
#{ Ref := #value{}=Entry } = Vs0,
Vs = Vs0#{ Ref => Entry#value{type=Type} },
Vst#vst{current=St#st{vs=Vs}}.
new_value(Type, Op, Ss, #vst{current=#st{vs=Vs0}=St,ref_ctr=Counter}=Vst) ->
Ref = #value_ref{id=Counter},
Vs = Vs0#{ Ref => #value{op=Op,args=Ss,type=Type} },
{Ref, Vst#vst{current=St#st{vs=Vs},ref_ctr=Counter+1}}.
kill_catch_tag(Reg, #vst{current=#st{ct=[Fail|Fails]}=St}=Vst0) ->
Vst = Vst0#vst{current=St#st{ct=Fails,fls=undefined}},
{_, Fail} = get_tag_type(Reg, Vst), %Assertion.
kill_tag(Reg, Vst).
check_try_catch_tags(Type, {y,N}=Reg, Vst) ->
%% Every catch or try/catch must use a lower Y register number than any
%% enclosing catch or try/catch. That will ensure that when the stack is
%% scanned when an exception occurs, the innermost try/catch tag is found
%% first.
case is_try_catch_tag(Type) of
true ->
case collect_try_catch_tags(N - 1, Vst, []) of
[_|_]=Bad -> error({bad_try_catch_nesting, Reg, Bad});
[] -> ok
end;
false ->
ok
end.
is_reg_defined({x,_}=Reg, #vst{current=#st{xs=Xs}}) -> is_map_key(Reg, Xs);
is_reg_defined({y,_}=Reg, #vst{current=#st{ys=Ys}}) -> is_map_key(Reg, Ys);
is_reg_defined(V, #vst{}) -> error({not_a_register, V}).
assert_term(Src, Vst) ->
_ = get_term_type(Src, Vst),
ok.
assert_movable(Src, Vst) ->
_ = get_movable_term_type(Src, Vst),
ok.
assert_literal(Src) ->
case is_literal(Src) of
true -> ok;
false -> error({literal_required,Src})
end.
assert_not_literal(Src) ->
case is_literal(Src) of
true -> error({literal_not_allowed,Src});
false -> ok
end.
is_literal(nil) -> true;
is_literal({atom,A}) when is_atom(A) -> true;
is_literal({float,F}) when is_float(F) -> true;
is_literal({integer,I}) when is_integer(I) -> true;
is_literal({literal,_L}) -> true;
is_literal(_) -> false.
%% `dialyzer` complains about the float and general literal cases never being
%% matched and I don't like suppressing warnings. Should they become possible
%% I'm sure `dialyzer` will warn about it.
value_to_literal([]) -> nil;
value_to_literal(A) when is_atom(A) -> {atom,A};
value_to_literal(I) when is_integer(I) -> {integer,I}.
%% These are just wrappers around their equivalents in beam_types, which
%% handle the validator-specific #t_abstract{} type.
%%
%% The funny-looking abstract types produced here are intended to provoke
%% errors on actual use; they do no harm just lying around.
normalize(#t_abstract{}=A) -> error({abstract_type, A});
normalize(T) -> beam_types:normalize(T).
join(Same, Same) -> Same;
join(#t_abstract{}=A, B) -> #t_abstract{kind={join, A, B}};
join(A, #t_abstract{}=B) -> #t_abstract{kind={join, A, B}};
join(A, B) -> beam_types:join(A, B).
meet(Same, Same) -> Same;
meet(#t_abstract{}=A, B) -> #t_abstract{kind={meet, A, B}};
meet(A, #t_abstract{}=B) -> #t_abstract{kind={meet, A, B}};
meet(A, B) -> beam_types:meet(A, B).
subtract(#t_abstract{}=A, B) -> #t_abstract{kind={subtract, A, B}};
subtract(A, #t_abstract{}=B) -> #t_abstract{kind={subtract, A, B}};
subtract(A, B) -> beam_types:subtract(A, B).
assert_type(RequiredType, Term, Vst) ->
GivenType = get_movable_term_type(Term, Vst),
case meet(RequiredType, GivenType) of
GivenType ->
ok;
_RequiredType ->
error({bad_type,{needed,RequiredType},{actual,GivenType}})
end.
validate_src(Ss, Vst) when is_list(Ss) ->
_ = [assert_term(S, Vst) || S <- Ss],
ok.
%% get_term_type(Src, ValidatorState) -> Type
%% Get the type of the source Src. The returned type Type will be
%% a standard Erlang type (no catch/try tags or match contexts).
get_term_type(Src, Vst) ->
case get_movable_term_type(Src, Vst) of
#t_bs_context{} -> error({match_context,Src});
#t_abstract{} -> error({abstract_term,Src});
Type -> Type
end.
%% get_movable_term_type(Src, ValidatorState) -> Type
%% Get the type of the source Src. The returned type Type will be
%% a standard Erlang type (no catch/try tags). Match contexts are OK.
get_movable_term_type(Src, Vst) ->
case get_raw_type(Src, Vst) of
#t_abstract{kind=unfinished_tuple=Kind} -> error({Kind,Src});
initialized -> error({unassigned,Src});
uninitialized -> error({uninitialized_reg,Src});
{catchtag,_} -> error({catchtag,Src});
{trytag,_} -> error({trytag,Src});
Type -> Type
end.
%% get_tag_type(Src, ValidatorState) -> Type
%% Return the tag type of a Y register, erroring out if it contains a term.
get_tag_type({y,_}=Src, Vst) ->
case get_raw_type(Src, Vst) of
{catchtag, _}=Tag -> Tag;
{trytag, _}=Tag -> Tag;
uninitialized=Tag -> Tag;
initialized=Tag -> Tag;
Other -> error({invalid_tag,Src,Other})
end;
get_tag_type(Src, _) ->
error({invalid_tag_register,Src}).
%% get_raw_type(Src, ValidatorState) -> Type
%% Return the type of a register without doing any validity checks or
%% conversions.
get_raw_type({x,X}=Src, #vst{current=#st{xs=Xs}}=Vst) when is_integer(X) ->
check_limit(Src),
case Xs of
#{ Src := #value_ref{}=Ref } -> get_raw_type(Ref, Vst);
#{} -> uninitialized
end;
get_raw_type({y,Y}=Src, #vst{current=#st{ys=Ys}}=Vst) when is_integer(Y) ->
check_limit(Src),
case Ys of
#{ Src := #value_ref{}=Ref } -> get_raw_type(Ref, Vst);
#{ Src := Tag } -> Tag;
#{} -> uninitialized
end;
get_raw_type(#value_ref{}=Ref, #vst{current=#st{vs=Vs}}) ->
case Vs of
#{ Ref := #value{type=Type} } -> Type;
#{} -> none
end;
get_raw_type(Src, #vst{}) ->
get_literal_type(Src).
is_value_alive(#value_ref{}=Ref, #vst{current=#st{vs=Vs}}) ->
is_map_key(Ref, Vs);
is_value_alive(_, _) ->
false.
get_literal_type(nil) ->
beam_types:make_type_from_value([]);
get_literal_type({atom,A}) when is_atom(A) ->
beam_types:make_type_from_value(A);
get_literal_type({float,F}) when is_float(F) ->
beam_types:make_type_from_value(F);
get_literal_type({integer,I}) when is_integer(I) ->
beam_types:make_type_from_value(I);
get_literal_type({literal,L}) ->
beam_types:make_type_from_value(L);
get_literal_type(T) ->
error({not_literal,T}).
%%%
%%% Branch tracking
%%%
%% Forks the execution flow, with the provided funs returning the new state of
%% their respective branch; the "fail" fun returns the state where the branch
%% is taken, and the "success" fun returns the state where it's not.
%%
%% If either path is known not to be taken at runtime (eg. due to a type
%% conflict), it will simply be discarded.
-spec branch(Lbl :: label(),
Original :: #vst{},
FailFun :: BranchFun,
SuccFun :: BranchFun) -> #vst{} when
BranchFun :: fun((#vst{}) -> #vst{}).
branch(Lbl, Vst0, FailFun, SuccFun) ->
#vst{current=St0} = Vst0,
try FailFun(Vst0) of
Vst1 ->
Vst2 = branch_state(Lbl, Vst1),
Vst = Vst2#vst{current=St0},
try SuccFun(Vst) of
V -> V
catch
{type_conflict, _, _} ->
%% The instruction is guaranteed to fail; kill the state.
kill_state(Vst)
end
catch
{type_conflict, _, _} ->
%% This instruction is guaranteed not to fail, so we run the
%% success branch *without* catching type conflicts to avoid hiding
%% errors in the validator itself; one of the branches must
%% succeed.
SuccFun(Vst0)
end.
%% A shorthand version of branch/4 for when the state is only altered on
%% success.
branch(Fail, Vst, SuccFun) ->
branch(Fail, Vst, fun(V) -> V end, SuccFun).
%% Directly branches off the state. This is an "internal" operation that should
%% be used sparingly.
branch_state(0, #vst{}=Vst) ->
%% If the instruction fails, the stack may be scanned looking for a catch
%% tag. Therefore the Y registers must be initialized at this point.
verify_y_init(Vst),
Vst;
branch_state(L, #vst{current=St,branched=B,ref_ctr=Counter0}=Vst) ->
case gb_trees:is_defined(L, B) of
true ->
{MergedSt, Counter} = merge_states(L, St, B, Counter0),
Branched = gb_trees:update(L, MergedSt, B),
Vst#vst{branched=Branched,ref_ctr=Counter};
false ->
Vst#vst{branched=gb_trees:insert(L, St, B)}
end.
%% merge_states/3 is used when there's more than one way to arrive at a
%% certain point, requiring the states to be merged down to the least
%% common subset for the subsequent code.
merge_states(L, St, Branched, Counter) when L =/= 0 ->
case gb_trees:lookup(L, Branched) of
none ->
{St, Counter};
{value,OtherSt} when St =:= none ->
{OtherSt, Counter};
{value,OtherSt} ->
merge_states_1(St, OtherSt, Counter)
end.
merge_states_1(#st{xs=XsA,ys=YsA,vs=VsA,fragile=FragA,numy=NumYA,h=HA,ct=CtA},
#st{xs=XsB,ys=YsB,vs=VsB,fragile=FragB,numy=NumYB,h=HB,ct=CtB},
Counter0) ->
%% When merging registers we drop all registers that aren't defined in both
%% states, and resolve conflicts by creating new values (similar to phi
%% nodes in SSA).
%%
%% While doing this we build a "merge map" detailing which values need to
%% be kept and which new values need to be created to resolve conflicts.
%% This map is then used to create a new value database where the types of
%% all values have been joined.
{Xs, Merge0, Counter1} = merge_regs(XsA, XsB, #{}, Counter0),
{Ys, Merge, Counter} = merge_regs(YsA, YsB, Merge0, Counter1),
Vs = merge_values(Merge, VsA, VsB),
Fragile = merge_fragility(FragA, FragB),
NumY = merge_stk(NumYA, NumYB),
Ct = merge_ct(CtA, CtB),
St = #st{xs=Xs,ys=Ys,vs=Vs,fragile=Fragile,numy=NumY,h=min(HA, HB),ct=Ct},
{St, Counter}.
%% Merges the contents of two register maps, returning the updated "merge map"
%% and the new registers.
merge_regs(RsA, RsB, Merge, Counter) ->
Keys = if
map_size(RsA) =< map_size(RsB) -> maps:keys(RsA);
map_size(RsA) > map_size(RsB) -> maps:keys(RsB)
end,
merge_regs_1(Keys, RsA, RsB, #{}, Merge, Counter).
merge_regs_1([Reg | Keys], RsA, RsB, Regs, Merge0, Counter0) ->
case {RsA, RsB} of
{#{ Reg := #value_ref{}=RefA }, #{ Reg := #value_ref{}=RefB }} ->
{Ref, Merge, Counter} = merge_vrefs(RefA, RefB, Merge0, Counter0),
merge_regs_1(Keys, RsA, RsB, Regs#{ Reg => Ref }, Merge, Counter);
{#{ Reg := TagA }, #{ Reg := TagB }} ->
%% Tags describe the state of the register rather than the value it
%% contains, so if a register contains a tag in one state we have
%% to merge it as a tag regardless of whether the other state says
%% it's a value.
{y, _} = Reg, %Assertion.
merge_regs_1(Keys, RsA, RsB, Regs#{ Reg => merge_tags(TagA,TagB) },
Merge0, Counter0);
{#{}, #{}} ->
merge_regs_1(Keys, RsA, RsB, Regs, Merge0, Counter0)
end;
merge_regs_1([], _, _, Regs, Merge, Counter) ->
{Regs, Merge, Counter}.
merge_tags(Same, Same) ->
Same;
merge_tags(uninitialized, _) ->
uninitialized;
merge_tags(_, uninitialized) ->
uninitialized;
merge_tags({catchtag,T0}, {catchtag,T1}) ->
{catchtag, ordsets:from_list(T0 ++ T1)};
merge_tags({trytag,T0}, {trytag,T1}) ->
{trytag, ordsets:from_list(T0 ++ T1)};
merge_tags(_A, _B) ->
%% All other combinations leave the register initialized. Errors arising
%% from this will be caught later on.
initialized.
merge_vrefs(Ref, Ref, Merge, Counter) ->
%% We have two (potentially) different versions of the same value, so we
%% should join their types into the same value.
{Ref, Merge#{ Ref => Ref }, Counter};
merge_vrefs(RefA, RefB, Merge, Counter) ->
%% We have two different values, so we need to create a new value from
%% their joined type if we haven't already done so.
Key = {RefA, RefB},
case Merge of
#{ Key := Ref } ->
{Ref, Merge, Counter};
#{} ->
Ref = #value_ref{id=Counter},
{Ref, Merge#{ Key => Ref }, Counter + 1}
end.
merge_values(Merge, VsA, VsB) ->
maps:fold(fun(Spec, New, Acc) ->
merge_values_1(Spec, New, VsA, VsB, Acc)
end, #{}, Merge).
merge_values_1(Same, Same, VsA, VsB, Acc) ->
%% We're merging different versions of the same value, so it's safe to
%% reuse old entries if the type's unchanged.
#value{type=TypeA}=EntryA = map_get(Same, VsA),
#value{type=TypeB}=EntryB = map_get(Same, VsB),
Entry = case join(TypeA, TypeB) of
TypeA -> EntryA;
TypeB -> EntryB;
JoinedType -> EntryA#value{type=JoinedType}
end,
Acc#{ Same => Entry };
merge_values_1({RefA, RefB}, New, VsA, VsB, Acc) ->
#value{type=TypeA} = map_get(RefA, VsA),
#value{type=TypeB} = map_get(RefB, VsB),
Acc#{ New => #value{op=join,args=[],type=join(TypeA, TypeB)} }.
merge_fragility(FragileA, FragileB) ->
cerl_sets:union(FragileA, FragileB).
merge_stk(S, S) -> S;
merge_stk(_, _) -> undecided.
merge_ct(S, S) -> S;
merge_ct(Ct0, Ct1) -> merge_ct_1(Ct0, Ct1).
merge_ct_1([C0|Ct0], [C1|Ct1]) ->
[ordsets:from_list(C0++C1)|merge_ct_1(Ct0, Ct1)];
merge_ct_1([], []) -> [];
merge_ct_1(_, _) -> undecided.
verify_y_init(#vst{current=#st{numy=NumY,ys=Ys}}=Vst) when is_integer(NumY) ->
HighestY = maps:fold(fun({y,Y}, _, Acc) -> max(Y, Acc) end, -1, Ys),
true = NumY > HighestY, %Assertion.
verify_y_init_1(NumY - 1, Vst),
ok;
verify_y_init(#vst{current=#st{numy=undecided,ys=Ys}}=Vst) ->
HighestY = maps:fold(fun({y,Y}, _, Acc) -> max(Y, Acc) end, -1, Ys),
verify_y_init_1(HighestY, Vst);
verify_y_init(#vst{}) ->
ok.
verify_y_init_1(-1, _Vst) ->
ok;
verify_y_init_1(Y, Vst) ->
Reg = {y, Y},
assert_not_fragile(Reg, Vst),
case get_raw_type(Reg, Vst) of
uninitialized -> error({uninitialized_reg,Reg});
_ -> verify_y_init_1(Y - 1, Vst)
end.
verify_live(0, _Vst) ->
ok;
verify_live(Live, Vst) when is_integer(Live), 0 < Live, Live =< 1023 ->
verify_live_1(Live - 1, Vst);
verify_live(Live, _Vst) ->
error({bad_number_of_live_regs,Live}).
verify_live_1(-1, _) ->
ok;
verify_live_1(X, Vst) when is_integer(X) ->
Reg = {x, X},
case get_raw_type(Reg, Vst) of
uninitialized -> error({Reg, not_live});
_ -> verify_live_1(X - 1, Vst)
end.
verify_no_ct(#vst{current=#st{numy=none}}) ->
ok;
verify_no_ct(#vst{current=#st{numy=undecided}}) ->
error(unknown_size_of_stackframe);
verify_no_ct(#vst{current=St}=Vst) ->
case collect_try_catch_tags(St#st.numy - 1, Vst, []) of
[_|_]=Bad -> error({unfinished_catch_try,Bad});
[] -> ok
end.
%% Collects all try/catch tags, walking down from the Nth stack position.
collect_try_catch_tags(-1, _Vst, Acc) ->
Acc;
collect_try_catch_tags(Y, Vst, Acc0) ->
Tag = get_raw_type({y, Y}, Vst),
Acc = case is_try_catch_tag(Tag) of
true -> [{{y, Y}, Tag} | Acc0];
false -> Acc0
end,
collect_try_catch_tags(Y - 1, Vst, Acc).
is_try_catch_tag({catchtag,_}) -> true;
is_try_catch_tag({trytag,_}) -> true;
is_try_catch_tag(_) -> false.
eat_heap(N, #vst{current=#st{h=Heap0}=St}=Vst) ->
case Heap0-N of
Neg when Neg < 0 ->
error({heap_overflow,{left,Heap0},{wanted,N}});
Heap ->
Vst#vst{current=St#st{h=Heap}}
end.
eat_heap_float(#vst{current=#st{hf=HeapFloats0}=St}=Vst) ->
case HeapFloats0-1 of
Neg when Neg < 0 ->
error({heap_overflow,{left,{HeapFloats0,floats}},{wanted,{1,floats}}});
HeapFloats ->
Vst#vst{current=St#st{hf=HeapFloats}}
end.
%%% FRAGILITY
%%%
%%% The loop_rec/2 instruction may return a reference to a term that is not
%%% part of the root set. That term or any part of it must not be included in a
%%% garbage collection. Therefore, the term (or any part of it) must not be
%%% passed to another function, placed in another term, or live in a Y register
%%% over an instruction that may GC.
%%%
%%% Fragility is marked on a per-register (rather than per-value) basis.
%% Marks Reg as fragile.
mark_fragile(Reg, Vst) ->
#vst{current=#st{fragile=Fragile0}=St0} = Vst,
Fragile = cerl_sets:add_element(Reg, Fragile0),
St = St0#st{fragile=Fragile},
Vst#vst{current=St}.
propagate_fragility(Reg, Args, #vst{current=St0}=Vst) ->
#st{fragile=Fragile0} = St0,
Sources = cerl_sets:from_list(Args),
Fragile = case cerl_sets:is_disjoint(Sources, Fragile0) of
true -> cerl_sets:del_element(Reg, Fragile0);
false -> cerl_sets:add_element(Reg, Fragile0)
end,
St = St0#st{fragile=Fragile},
Vst#vst{current=St}.
%% Marks Reg as durable, must be used when assigning a newly created value to
%% a register.
remove_fragility(Reg, Vst) ->
#vst{current=#st{fragile=Fragile0}=St0} = Vst,
case cerl_sets:is_element(Reg, Fragile0) of
true ->
Fragile = cerl_sets:del_element(Reg, Fragile0),
St = St0#st{fragile=Fragile},
Vst#vst{current=St};
false ->
Vst
end.
%% Marks all registers as durable.
remove_fragility(#vst{current=St0}=Vst) ->
St = St0#st{fragile=cerl_sets:new()},
Vst#vst{current=St}.
assert_durable_term(Src, Vst) ->
assert_term(Src, Vst),
assert_not_fragile(Src, Vst).
assert_not_fragile({Kind,_}=Src, Vst) when Kind =:= x; Kind =:= y ->
check_limit(Src),
#vst{current=#st{fragile=Fragile}} = Vst,
case cerl_sets:is_element(Src, Fragile) of
true -> error({fragile_message_reference, Src});
false -> ok
end;
assert_not_fragile(Lit, #vst{}) ->
assert_literal(Lit),
ok.
%%%
%%% Return/argument types of calls and BIFs
%%%
bif_types(Op, Ss, Vst) ->
Args = [normalize(get_term_type(Arg, Vst)) || Arg <- Ss],
beam_call_types:types(erlang, Op, Args).
call_types({extfunc,M,F,A}, A, Vst) ->
Args = get_call_args(A, Vst),
beam_call_types:types(M, F, Args);
call_types(_, A, Vst) ->
{any, get_call_args(A, Vst), false}.
get_call_args(Arity, Vst) ->
get_call_args_1(0, Arity, Vst).
get_call_args_1(Arity, Arity, _) ->
[];
get_call_args_1(N, Arity, Vst) when N < Arity ->
ArgType = normalize(get_movable_term_type({x,N}, Vst)),
[ArgType | get_call_args_1(N + 1, Arity, Vst)].
check_limit({x,X}=Src) when is_integer(X) ->
if
%% Note: x(1023) is reserved for use by the BEAM loader.
0 =< X, X < 1023 -> ok;
1023 =< X -> error(limit);
X < 0 -> error({bad_register, Src})
end;
check_limit({y,Y}=Src) when is_integer(Y) ->
if
0 =< Y, Y < 1024 -> ok;
1024 =< Y -> error(limit);
Y < 0 -> error({bad_register, Src})
end;
check_limit({fr,Fr}=Src) when is_integer(Fr) ->
if
0 =< Fr, Fr < 1023 -> ok;
1023 =< Fr -> error(limit);
Fr < 0 -> error({bad_register, Src})
end.
min(A, B) when is_integer(A), is_integer(B), A < B -> A;
min(A, B) when is_integer(A), is_integer(B) -> B.
gb_trees_from_list(L) -> gb_trees:from_orddict(sort(L)).
error(Error) -> throw(Error).