%% ``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.
%%
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%% $Id: beam_validator.erl,v 1.1 2008/12/17 09:53:41 mikpe Exp $
-module(beam_validator).
-export([file/1,files/1]).
%% Interface for compiler.
-export([module/2,format_error/1]).
-import(lists, [reverse/1,foldl/3]).
-define(MAXREG, 1024).
-define(DEBUG, 1).
-undef(DEBUG).
-ifdef(DEBUG).
-define(DBG_FORMAT(F, D), (io:format((F), (D)))).
-else.
-define(DBG_FORMAT(F, D), ok).
-endif.
%%%
%%% API functions.
%%%
files([F|Fs]) ->
?DBG_FORMAT("# Verifying: ~p~n", [F]),
case file(F) of
ok -> ok;
{error,Es} ->
io:format("~p:~n~s~n", [F,format_error(Es)])
end,
files(Fs);
files([]) -> ok.
file(Name) when is_list(Name) ->
case case filename:extension(Name) of
".S" -> s_file(Name);
".beam" -> beam_file(Name)
end of
[] -> ok;
Es -> {error,Es}
end.
%% To be called by the compiler.
module({Mod,Exp,Attr,Fs,Lc}=Code, _Opts)
when is_atom(Mod), is_list(Exp), is_list(Attr), is_integer(Lc) ->
case validate(Fs) of
[] -> {ok,Code};
Es0 ->
Es = [{?MODULE,E} || E <- Es0],
{error,[{atom_to_list(Mod),Es}]}
end.
format_error([]) -> [];
format_error([{{M,F,A},{I,Off,Desc}}|Es]) ->
[io_lib:format(" ~p:~p/~p+~p:~n ~p - ~p~n",
[M,F,A,Off,I,Desc])|format_error(Es)];
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]).
%%%
%%% Local functions follow.
%%%
s_file(Name) ->
{ok,Is} = file:consult(Name),
Fs = find_functions(Is),
validate(Fs).
find_functions(Fs) ->
find_functions_1(Fs, none, [], []).
find_functions_1([{function,Name,Arity,Entry}|Is], Func, FuncAcc, Acc0) ->
Acc = add_func(Func, FuncAcc, Acc0),
find_functions_1(Is, {Name,Arity,Entry}, [], Acc);
find_functions_1([I|Is], Func, FuncAcc, Acc) ->
find_functions_1(Is, Func, [I|FuncAcc], Acc);
find_functions_1([], Func, FuncAcc, Acc) ->
reverse(add_func(Func, FuncAcc, Acc)).
add_func(none, _, Acc) -> Acc;
add_func({Name,Arity,Entry}, Is, Acc) ->
[{function,Name,Arity,Entry,reverse(Is)}|Acc].
beam_file(Name) ->
try beam_disasm:file(Name) of
{error,beam_lib,Reason} -> [{beam_lib,Reason}];
{beam_file,L} ->
{value,{code,Code0}} = lists:keysearch(code, 1, L),
Code = beam_file_1(Code0, []),
validate(Code)
catch _:_ -> [disassembly_failed]
end.
beam_file_1([F0|Fs], Acc) ->
F = conv_func(F0),
beam_file_1(Fs, [F|Acc]);
beam_file_1([], Acc) -> reverse(Acc).
%% Convert from the disassembly format to the internal format
%% used by the compiler (as passed to the assembler).
conv_func(Is) ->
conv_func_1(labels(Is)).
conv_func_1({Ls,[{func_info,[{atom,M},{atom,F},Ar]},
{label,Entry}=Le|Is]}) ->
%% The entry label gets maybe not correct here
{function,F,Ar,Entry,
[{label,L}||L<-Ls]++[{func_info,{atom,M},{atom,F},Ar},Le|Is]}.
%%%
%%% The validator follows.
%%%
%%% The purpose of the validator is 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
%%%
%%% - That floating point registers are initialized before used.
%%% - That fclearerror and fcheckerror are used properly.
%%% - Heap allocation for floating point numbers.
%%% - Heap allocation for binaries.
%%% - That a catchtag or trytag is not overwritten by the wrong
%%% type of instruction (such as move/2).
%%% - Make sure that all catchtags and trytags have been removed
%%% from the stack at return/tail call.
%%% - Verify get_list instructions.
%%%
%% validate([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([]) -> [];
validate([{function,Name,Ar,Entry,Code}|Fs]) ->
try validate_1(Code, Name, Ar, Entry) of
_ -> validate(Fs)
catch
Error ->
[Error|validate(Fs)];
error:Error ->
[validate_error(Error, Name, Ar)|validate(Fs)]
end.
-ifdef(DEBUG).
validate_error(Error, Name, Ar) ->
exit(validate_error_1(Error, Name, Ar)).
-else.
validate_error(Error, Name, Ar) ->
validate_error_1(Error, Name, Ar).
-endif.
validate_error_1(Error, Name, Ar) ->
{{'_',Name,Ar},
{internal_error,'_',{Error,erlang:get_stacktrace()}}}.
-record(st, %Emulation state
{x=init_regs(0, term), %x register info.
y=init_regs(0, initialized), %y register info.
numy=none, %Number of y registers.
h=0, %Available heap size.
ct=[] %List of hot catch/try labels
}).
-record(vst, %Validator state
{current=none, %Current state
branched=gb_trees:empty() %States at jumps
}).
-ifdef(DEBUG).
print_st(#st{x=Xs,y=Ys,numy=NumY,h=H,ct=Ct}) ->
io:format(" #st{x=~p~n"
" y=~p~n"
" numy=~p,h=~p,ct=~w~n",
[gb_trees:to_list(Xs),gb_trees:to_list(Ys),NumY,H,Ct]).
-endif.
validate_1(Is, Name, Arity, Entry) ->
validate_2(labels(Is), Name, Arity, Entry).
validate_2({Ls1,[{func_info,{atom,Mod},{atom,Name},Arity}=_F|Is]},
Name, Arity, Entry) ->
lists:foreach(fun (_L) -> ?DBG_FORMAT(" ~p.~n", [_L]) end, Ls1),
?DBG_FORMAT(" ~p.~n", [_F]),
validate_3(labels(Is), Name, Arity, Entry, Mod, Ls1);
validate_2({Ls1,Is}, Name, Arity, _Entry) ->
error({{'_',Name,Arity},{first(Is),length(Ls1),illegal_instruction}}).
validate_3({Ls2,Is}, Name, Arity, Entry, Mod, Ls1) ->
lists:foreach(fun (_L) -> ?DBG_FORMAT(" ~p.~n", [_L]) end, Ls2),
Offset = 1 + length(Ls2),
case lists:member(Entry, Ls2) of
true ->
St = init_state(Arity),
Vst = #vst{current=St,
branched=gb_trees_from_list([{L,St} || L <- Ls1])},
valfun(Is, {Mod,Name,Arity}, Offset, Vst);
false ->
error({{Mod,Name,Arity},{first(Is),Offset,no_entry_label}})
end.
first([X|_]) -> X;
first([]) -> [].
labels(Is) ->
labels_1(Is, []).
labels_1([{label,L}|Is], R) ->
labels_1(Is, [L|R]);
labels_1(Is, R) ->
{lists:reverse(R),Is}.
init_state(Arity) ->
Xs = init_regs(Arity, term),
Ys = init_regs(0, initialized),
#st{x=Xs,y=Ys,numy=none,h=0,ct=[]}.
init_regs(0, _) ->
gb_trees:empty();
init_regs(N, Type) ->
gb_trees_from_list([{R,Type} || R <- lists:seq(0, N-1)]).
valfun([], _MFA, _Offset, Vst) -> Vst;
valfun([I|Is], MFA, Offset, Vst) ->
?DBG_FORMAT(" ~p.\n", [I]),
valfun(Is, MFA, Offset+1,
try 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,branched=B}=Vst) ->
St = merge_states(Lbl, St0, B),
Vst#vst{current=St,branched=gb_trees:enter(Lbl, St, B)};
valfun_1(_I, #vst{current=none}=Vst) ->
%% Ignore instructions after erlang:error/1,2, which
%% the original R10B compiler thought would return.
?DBG_FORMAT("Ignoring ~p\n", [_I]),
Vst;
valfun_1({badmatch,Src}, Vst) ->
assert_term(Src, Vst),
kill_state(Vst);
valfun_1({case_end,Src}, Vst) ->
assert_term(Src, Vst),
kill_state(Vst);
valfun_1(if_end, Vst) ->
kill_state(Vst);
valfun_1({try_case_end,Src}, Vst) ->
assert_term(Src, Vst),
kill_state(Vst);
%% Instructions that can not cause exceptions
valfun_1({move,Src,Dst}, Vst) ->
Type = get_term_type(Src, Vst),
set_type_reg(Type, Dst, Vst);
valfun_1({fmove,Src,{fr,_}}, Vst) ->
assert_type(float, Src, Vst);
valfun_1({fmove,{fr,_},Dst}, Vst) ->
set_type_reg({float,[]}, Dst, Vst);
valfun_1({kill,{y,_}=Reg}, Vst) ->
set_type_y(initialized, Reg, Vst);
valfun_1({test_heap,Heap,Live}, Vst) ->
test_heap(Heap, Live, Vst);
valfun_1({bif,_Op,nofail,Src,Dst}, Vst) ->
validate_src(Src, Vst),
set_type_reg(term, Dst, Vst);
%% Put instructions.
valfun_1({put_list,A,B,Dst}, Vst0) ->
assert_term(A, Vst0),
assert_term(B, Vst0),
Vst = eat_heap(2, Vst0),
set_type_reg(cons, Dst, Vst);
valfun_1({put_tuple,Sz,Dst}, Vst0) when is_integer(Sz) ->
Vst = eat_heap(1, Vst0),
set_type_reg({tuple,Sz}, Dst, Vst);
valfun_1({put,Src}, Vst) ->
assert_term(Src, Vst),
eat_heap(1, Vst);
valfun_1({put_string,Sz,_,Dst}, Vst0) when is_integer(Sz) ->
Vst = eat_heap(2*Sz, Vst0),
set_type_reg(cons, Dst, Vst);
%% Allocate and deallocate, et.al
valfun_1({allocate,Stk,Live}, Vst) ->
allocate(false, Stk, 0, Live, Vst);
valfun_1({allocate_heap,Stk,Heap,Live}, Vst) ->
allocate(false, Stk, Heap, Live, Vst);
valfun_1({allocate_zero,Stk,Live}, Vst) ->
allocate(true, Stk, 0, Live, Vst);
valfun_1({allocate_heap_zero,Stk,Heap,Live}, Vst) ->
allocate(true, Stk, Heap, Live, Vst);
valfun_1({init,{y,_}=Reg}, Vst) ->
set_type_y(initialized, Reg, Vst);
valfun_1({deallocate,StkSize}, #vst{current=#st{numy=StkSize,ct=[]}}=Vst) ->
deallocate(Vst);
valfun_1({deallocate,_}, #vst{current=#st{numy=NumY,ct=[]}}) ->
error({allocated,NumY});
valfun_1({deallocate,_}, #vst{current=#st{ct=Fails}}) ->
error({catch_try_stack,Fails});
%% Catch & try.
valfun_1({'catch',Dst,{f,Fail}}, Vst0) when Fail /= none ->
Vst = #vst{current=#st{ct=Fails}=St} =
set_type_y({catchtag,Fail}, Dst, Vst0),
Vst#vst{current=St#st{ct=[Fail|Fails]}};
valfun_1({'try',Dst,{f,Fail}}, Vst0) ->
Vst = #vst{current=#st{ct=Fails}=St} =
set_type_y({trytag,Fail}, Dst, Vst0),
Vst#vst{current=St#st{ct=[Fail|Fails]}};
%% Do a postponed state branch if necessary and try next set of instructions
valfun_1(I, #vst{current=#st{ct=[]}}=Vst) ->
valfun_2(I, Vst);
valfun_1(I, #vst{current=#st{ct=Fails}}=Vst0) ->
%% Perform a postponed state branch
Vst = #vst{current=St} = lists:foldl(fun branch_state/2, Vst0, Fails),
valfun_2(I, Vst#vst{current=St#st{ct=[]}}).
%% Instructions that can cause exceptions.
valfun_2({apply,Live}, Vst) ->
call(Live+2, Vst);
valfun_2({apply_last,Live,_}, Vst) ->
tail_call(Live+2, Vst);
valfun_2({call_fun,Live}, Vst) ->
call(Live, Vst);
valfun_2({call,Live,_}, Vst) ->
call(Live, Vst);
valfun_2({call_ext,Live,Func}, Vst) ->
call(Func, Live, Vst);
valfun_2({call_only,Live,_}, Vst) ->
tail_call(Live, Vst);
valfun_2({call_ext_only,Live,_}, Vst) ->
tail_call(Live, Vst);
valfun_2({call_last,Live,_,_}, Vst) ->
tail_call(Live, Vst);
valfun_2({call_ext_last,Live,_,_}, Vst) ->
tail_call(Live, Vst);
valfun_2({make_fun,_,_,Live}, Vst) ->
call(Live, Vst);
valfun_2({make_fun2,_,_,_,Live}, Vst) ->
call(Live, Vst);
%% Floating point.
valfun_2({fconv,Src,{fr,_}}, Vst) ->
assert_term(Src, Vst);
valfun_2({bif,fadd,_,[{fr,_},{fr,_}],{fr,_}}, Vst) ->
Vst;
valfun_2({bif,fdiv,_,[{fr,_},{fr,_}],{fr,_}}, Vst) ->
Vst;
valfun_2({bif,fmul,_,[{fr,_},{fr,_}],{fr,_}}, Vst) ->
Vst;
valfun_2({bif,fnegate,_,[{fr,_}],{fr,_}}, Vst) ->
Vst;
valfun_2({bif,fsub,_,[{fr,_},{fr,_}],{fr,_}}, Vst) ->
Vst;
valfun_2(fclearerror, Vst) ->
Vst;
valfun_2({fcheckerror,_}, Vst) ->
Vst;
%% Other BIFs
valfun_2({bif,element,{f,Fail},[Pos,Tuple],Dst}, Vst0) ->
TupleType0 = get_term_type(Tuple, Vst0),
PosType = get_term_type(Pos, Vst0),
Vst1 = branch_state(Fail, Vst0),
TupleType = upgrade_type({tuple,[get_tuple_size(PosType)]}, TupleType0),
Vst = set_type(TupleType, Tuple, Vst1),
set_type_reg(term, Dst, Vst);
valfun_2({bif,Op,{f,Fail},Src,Dst}, Vst0) ->
validate_src(Src, Vst0),
Vst = branch_state(Fail, Vst0),
Type = bif_type(Op, Src, Vst),
set_type_reg(Type, Dst, Vst);
valfun_2(return, #vst{current=#st{numy=none}}=Vst) ->
kill_state(Vst);
valfun_2(return, #vst{current=#st{numy=NumY}}) ->
error({stack_frame,NumY});
valfun_2({jump,{f,_}}, #vst{current=none}=Vst) ->
%% Must be an unreachable jump which was not optimized away.
%% Do nothing.
Vst;
valfun_2({jump,{f,Lbl}}, Vst) ->
kill_state(branch_state(Lbl, Vst));
valfun_2({loop_rec,{f,Fail},Dst}, Vst0) ->
Vst = branch_state(Fail, Vst0),
set_type_reg(term, Dst, Vst);
valfun_2(remove_message, Vst) ->
Vst;
valfun_2({wait,_}, Vst) ->
kill_state(Vst);
valfun_2({wait_timeout,_,Src}, Vst) ->
assert_term(Src, Vst);
valfun_2({loop_rec_end,_}, Vst) ->
kill_state(Vst);
valfun_2(timeout, #vst{current=St}=Vst) ->
Vst#vst{current=St#st{x=init_regs(0, term)}};
valfun_2(send, Vst) ->
call(2, Vst);
%% Catch & try.
valfun_2({catch_end,Reg}, Vst0) ->
case get_type(Reg, Vst0) of
{catchtag,_} ->
Vst = #vst{current=St} = set_type_reg(initialized, Reg, Vst0),
Xs = gb_trees_from_list([{0,term}]),
Vst#vst{current=St#st{x=Xs}};
Type ->
error({bad_type,Type})
end;
valfun_2({try_end,Reg}, Vst) ->
case get_type(Reg, Vst) of
{trytag,_} ->
set_type_reg(initialized, Reg, Vst);
Type ->
error({bad_type,Type})
end;
valfun_2({try_case,Reg}, Vst0) ->
case get_type(Reg, Vst0) of
{trytag,_} ->
Vst = #vst{current=St} = set_type_reg(initialized, Reg, Vst0),
Xs = gb_trees_from_list([{0,{atom,[]}},{1,term},{2,term}]),
Vst#vst{current=St#st{x=Xs}};
Type ->
error({bad_type,Type})
end;
valfun_2({set_tuple_element,Src,Tuple,I}, Vst) ->
assert_term(Src, Vst),
assert_type({tuple_element,I+1}, Tuple, Vst);
%% Match instructions.
valfun_2({select_val,Src,{f,Fail},{list,Choices}}, Vst) ->
assert_term(Src, Vst),
Lbls = [L || {f,L} <- Choices]++[Fail],
kill_state(foldl(fun(L, S) -> branch_state(L, S) end, Vst, Lbls));
valfun_2({select_tuple_arity,Tuple,{f,Fail},{list,Choices}}, Vst) ->
assert_type(tuple, Tuple, Vst),
kill_state(branch_arities(Choices, Tuple, branch_state(Fail, Vst)));
valfun_2({get_list,Src,D1,D2}, Vst0) ->
assert_term(Src, Vst0),
Vst = set_type_reg(term, D1, Vst0),
set_type_reg(term, D2, Vst);
valfun_2({get_tuple_element,Src,I,Dst}, Vst) ->
assert_type({tuple_element,I+1}, Src, Vst),
set_type_reg(term, Dst, Vst);
valfun_2({bs_restore,_}, Vst) ->
Vst;
valfun_2({bs_save,_}, Vst) ->
Vst;
valfun_2({bs_start_match,{f,Fail},Src}, Vst) ->
assert_term(Src, Vst),
branch_state(Fail, Vst);
valfun_2({test,bs_skip_bits,{f,Fail},[Src,_,_]}, Vst) ->
assert_term(Src, Vst),
branch_state(Fail, Vst);
valfun_2({test,_,{f,Fail},[_,_,_,Dst]}, Vst0) ->
Vst = branch_state(Fail, Vst0),
set_type_reg({integer,[]}, Dst, Vst);
valfun_2({test,bs_test_tail,{f,Fail},_}, Vst) ->
branch_state(Fail, Vst);
%% Other test instructions.
valfun_2({test,is_float,{f,Lbl},[Float]}, Vst0) ->
assert_term(Float, Vst0),
Vst = branch_state(Lbl, Vst0),
set_type({float,[]}, Float, Vst);
valfun_2({test,is_tuple,{f,Lbl},[Tuple]}, Vst0) ->
assert_term(Tuple, Vst0),
Vst = branch_state(Lbl, Vst0),
set_type({tuple,[0]}, Tuple, Vst);
valfun_2({test,test_arity,{f,Lbl},[Tuple,Sz]}, Vst0) when is_integer(Sz) ->
assert_type(tuple, Tuple, Vst0),
Vst = branch_state(Lbl, Vst0),
set_type_reg({tuple,Sz}, Tuple, Vst);
valfun_2({test,_Op,{f,Lbl},Src}, Vst) ->
validate_src(Src, Vst),
branch_state(Lbl, Vst);
valfun_2({bs_add,{f,Fail},[A,B,_],Dst}, Vst0) ->
assert_term(A, Vst0),
assert_term(B, Vst0),
Vst = branch_state(Fail, Vst0),
set_type_reg({integer,[]}, Dst, Vst);
valfun_2({bs_bits_to_bytes,{f,Fail},Src,Dst}, Vst0) ->
assert_term(Src, Vst0),
Vst = branch_state(Fail, Vst0),
set_type_reg({integer,[]}, Dst, Vst);
valfun_2({bs_init2,{f,Fail},_,Heap,_,_,Dst}, Vst0) ->
Vst1 = heap_alloc(Heap, Vst0),
Vst = branch_state(Fail, Vst1),
set_type_reg(binary, Dst, Vst);
valfun_2({bs_put_string,Sz,_}, Vst) when is_integer(Sz) ->
Vst;
valfun_2({bs_put_binary,{f,Fail},_,_,_,Src}, Vst0) ->
assert_term(Src, Vst0),
branch_state(Fail, Vst0);
valfun_2({bs_put_float,{f,Fail},_,_,_,Src}, Vst0) ->
assert_term(Src, Vst0),
branch_state(Fail, Vst0);
valfun_2({bs_put_integer,{f,Fail},_,_,_,Src}, Vst0) ->
assert_term(Src, Vst0),
branch_state(Fail, Vst0);
%% Old bit syntax construction (before R10B).
valfun_2({bs_init,_,_}, Vst) -> Vst;
valfun_2({bs_need_buf,_}, Vst) -> Vst;
valfun_2({bs_final,{f,Fail},Dst}, Vst0) ->
Vst = branch_state(Fail, Vst0),
set_type_reg(binary, Dst, Vst);
%% Misc.
valfun_2({'%live',Live}, Vst) ->
verify_live(Live, Vst),
Vst;
valfun_2(_, _) ->
error(unknown_instruction).
kill_state(#vst{current=#st{ct=[]}}=Vst) ->
Vst#vst{current=none};
kill_state(#vst{current=#st{ct=Fails}}=Vst0) ->
Vst = lists:foldl(fun branch_state/2, Vst0, Fails),
Vst#vst{current=none}.
%% A "plain" call.
%% The stackframe must have a known size and be initialized.
%% The instruction will return to the instruction following the call.
call(Live, #vst{current=St}=Vst) ->
verify_live(Live, Vst),
verify_y_init(Vst),
Xs = gb_trees_from_list([{0,term}]),
Vst#vst{current=St#st{x=Xs}}.
%% A "plain" call.
%% The stackframe must have a known size and be initialized.
%% The instruction will return to the instruction following the call.
call(Name, Live, #vst{current=St}=Vst) ->
verify_live(Live, Vst),
case return_type(Name, Vst) of
exception ->
kill_state(Vst);
Type ->
verify_y_init(Vst),
Xs = gb_trees_from_list([{0,Type}]),
Vst#vst{current=St#st{x=Xs}}
end.
%% Tail call.
%% The stackframe must have a known size and be initialized.
%% Does not return to the instruction following the call.
tail_call(Live, Vst) ->
kill_state(call(Live, Vst)).
allocate(Zero, Stk, Heap, Live, #vst{current=#st{numy=none}=St}=Vst) ->
verify_live(Live, Vst),
Ys = init_regs(case Zero of
true -> Stk;
false -> 0
end, initialized),
Vst#vst{current=St#st{y=Ys,numy=Stk,h=heap_alloc_1(Heap)}};
allocate(_, _, _, _, #vst{current=#st{numy=Numy}}) ->
error({existing_stack_frame,{size,Numy}}).
deallocate(#vst{current=St}=Vst) ->
Vst#vst{current=St#st{y=init_regs(0, initialized),numy=none}}.
test_heap(Heap, Live, Vst) ->
verify_live(Live, Vst),
heap_alloc(Heap, Vst).
heap_alloc(Heap, #vst{current=St}=Vst) ->
Vst#vst{current=St#st{h=heap_alloc_1(Heap)}}.
heap_alloc_1({alloc,Alloc}) ->
{value,{_,Heap}} = lists:keysearch(words, 1, Alloc),
Heap;
heap_alloc_1(Heap) when is_integer(Heap) -> Heap.
set_type(Type, {x,_}=Reg, Vst) -> set_type_reg(Type, Reg, Vst);
set_type(Type, {y,_}=Reg, Vst) -> set_type_y(Type, Reg, Vst);
set_type(_, _, #vst{}=Vst) -> Vst.
set_type_reg(Type, {x,X}, #vst{current=#st{x=Xs}=St}=Vst)
when 0 =< X, X < ?MAXREG ->
Vst#vst{current=St#st{x=gb_trees:enter(X, Type, Xs)}};
set_type_reg(Type, Reg, Vst) ->
set_type_y(Type, Reg, Vst).
set_type_y(Type, {y,Y}=Reg, #vst{current=#st{y=Ys,numy=NumY}=St}=Vst)
when is_integer(Y), 0 =< Y, Y < ?MAXREG ->
case {Y,NumY} of
{_,none} ->
error({no_stack_frame,Reg});
{_,_} when Y > NumY ->
error({y_reg_out_of_range,Reg,NumY});
{_,_} ->
Vst#vst{current=St#st{y=gb_trees:enter(Y, Type, Ys)}}
end;
set_type_y(Type, Reg, #vst{}) -> error({invalid_store,Reg,Type}).
assert_term(Src, Vst) ->
get_term_type(Src, Vst),
Vst.
%% The possible types.
%%
%% First non-term types:
%%
%% initialized Only for Y registers. Means that the Y 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).
%%
%% {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.
%%
%% exception Can only be used as a type returned by return_type/2
%% (which gives the type of the value returned by a BIF).
%% Thus 'exception' is never stored as type descriptor
%% for a register.
%%
%% Normal terms:
%%
%% term Any valid Erlang (but not of the special types above).
%%
%% bool The atom 'true' or the atom 'false'.
%%
%% cons Cons cell: [_|_]
%%
%% nil Empty list: []
%%
%% {tuple,[Sz]} Tuple. An element has been accessed using
%% element/2 or setelement/3 so that it is known that
%% the type is a tuple of size at least Sz.
%%
%% {tuple,Sz} Tuple. A test_arity instruction has been seen
%% so that it is known that the size is exactly Sz.
%%
%% {atom,[]} Atom.
%% {atom,Atom}
%%
%% {integer,[]} Integer.
%% {integer,Integer}
%%
%% {float,[]} Float.
%% {float,Float}
%%
%% number Integer or Float of unknown value
%%
assert_type(WantedType, Term, Vst) ->
assert_type(WantedType, get_type(Term, Vst)),
Vst.
assert_type(float, {float,_}) -> ok;
assert_type(tuple, {tuple,_}) -> ok;
assert_type({tuple_element,I}, {tuple,[Sz]})
when 1 =< I, I =< Sz ->
ok;
assert_type({tuple_element,I}, {tuple,Sz})
when is_integer(Sz), 1 =< I, I =< Sz ->
ok;
assert_type(Needed, Actual) ->
error({bad_type,{needed,Needed},{actual,Actual}}).
%% upgrade_type/2 is used when linear code finds out more and
%% more information about a type, so the type gets "narrower"
%% or perhaps inconsistent. In the case of inconsistency
%% we mostly widen the type to 'term' to make subsequent
%% code fail if it assumes anything about the type.
upgrade_type(Same, Same) -> Same;
upgrade_type(term, OldT) -> OldT;
upgrade_type(NewT, term) -> NewT;
upgrade_type({Type,New}=NewT, {Type,Old}=OldT)
when Type == atom; Type == integer; Type == float ->
if New =:= Old -> OldT;
New =:= [] -> OldT;
Old =:= [] -> NewT;
true -> term
end;
upgrade_type({Type,_}=NewT, number)
when Type == integer; Type == float ->
NewT;
upgrade_type(number, {Type,_}=OldT)
when Type == integer; Type == float ->
OldT;
upgrade_type(bool, {atom,A}) ->
upgrade_bool(A);
upgrade_type({atom,A}, bool) ->
upgrade_bool(A);
upgrade_type({tuple,[Sz]}, {tuple,[OldSz]})
when is_integer(Sz) ->
{tuple,[max(Sz, OldSz)]};
upgrade_type({tuple,Sz}=T, {tuple,[_]})
when is_integer(Sz) ->
%% This also takes care of the user error when a tuple element
%% is accesed outside the known exact tuple size; there is
%% no more type information, just a runtime error which is not
%% our problem.
T;
upgrade_type({tuple,[Sz]}, {tuple,_}=T)
when is_integer(Sz) ->
%% Same as the previous clause but mirrored.
T;
upgrade_type(_A, _B) ->
%%io:format("upgrade_type: ~p ~p\n", [_A,_B]),
term.
upgrade_bool([]) -> bool;
upgrade_bool(true) -> {atom,true};
upgrade_bool(false) -> {atom,false};
upgrade_bool(_) -> term.
get_tuple_size({integer,[]}) -> 0;
get_tuple_size({integer,Sz}) -> Sz;
get_tuple_size(_) -> 0.
validate_src(Ss, Vst) when is_list(Ss) ->
foldl(fun(S, _) -> get_type(S, Vst) end, ok, Ss).
get_term_type(Src, Vst) ->
case get_type(Src, Vst) of
initialized -> error({not_assigned,Src});
exception -> error({exception,Src});
{catchtag,_} -> error({catchtag,Src});
{trytag,_} -> error({trytag,Src});
Type -> Type
end.
get_type(nil=T, _) -> T;
get_type({atom,A}=T, _) when is_atom(A) -> T;
get_type({float,F}=T, _) when is_float(F) -> T;
get_type({integer,I}=T, _) when is_integer(I) -> T;
get_type({x,X}=Reg, #vst{current=#st{x=Xs}}) when is_integer(X) ->
case gb_trees:lookup(X, Xs) of
{value,Type} -> Type;
none -> error({uninitialized_reg,Reg})
end;
get_type({y,Y}=Reg, #vst{current=#st{y=Ys}}) when is_integer(Y) ->
case gb_trees:lookup(Y, Ys) of
{value,initialized} -> error({unassigned_reg,Reg});
{value,Type} -> Type;
none -> error({uninitialized_reg,Reg})
end;
get_type(Src, _) -> error({bad_source,Src}).
branch_arities([], _, #vst{}=Vst) -> Vst;
branch_arities([Sz,{f,L}|T], Tuple, #vst{current=St}=Vst0)
when is_integer(Sz) ->
Vst1 = set_type_reg({tuple,Sz}, Tuple, Vst0),
Vst = branch_state(L, Vst1),
branch_arities(T, Tuple, Vst#vst{current=St}).
branch_state(0, #vst{}=Vst) -> Vst;
branch_state(L, #vst{current=St,branched=B}=Vst) ->
Vst#vst{
branched=case gb_trees:is_defined(L, B) of
false ->
gb_trees:insert(L, St#st{ct=[]}, B);
true ->
MergedSt = merge_states(L, St, B),
gb_trees:update(L, MergedSt#st{ct=[]}, B)
end}.
%% merge_states/3 is used when there are more than one way to arrive
%% at this point, and the type states for the different paths has
%% to be merged. The type states are downgraded to the least common
%% subset for the subsequent code.
merge_states(0, St, _Branched) -> St;
merge_states(L, St, Branched) ->
case gb_trees:lookup(L, Branched) of
none -> St;
{value,OtherSt} when St == none -> OtherSt;
{value,OtherSt} ->
merge_states_1(St, OtherSt)
end.
merge_states_1(#st{x=Xs0,y=Ys0,numy=NumY0,h=H0}=St,
#st{x=Xs1,y=Ys1,numy=NumY1,h=H1}) ->
NumY = merge_stk(NumY0, NumY1),
Xs = merge_regs(Xs0, Xs1),
Ys = merge_regs(Ys0, Ys1),
St#st{x=Xs,y=Ys,numy=NumY,h=min(H0, H1)}.
merge_stk(S, S) -> S;
merge_stk(_, _) -> undecided.
merge_regs(Rs0, Rs1) ->
Rs = merge_regs_1(gb_trees:to_list(Rs0), gb_trees:to_list(Rs1)),
gb_trees_from_list(Rs).
merge_regs_1([Same|Rs1], [Same|Rs2]) ->
[Same|merge_regs_1(Rs1, Rs2)];
merge_regs_1([{R1,_}|Rs1], [{R2,_}|_]=Rs2) when R1 < R2 ->
merge_regs_1(Rs1, Rs2);
merge_regs_1([{R1,_}|_]=Rs1, [{R2,_}|Rs2]) when R1 > R2 ->
merge_regs_1(Rs1, Rs2);
merge_regs_1([{R,Type1}|Rs1], [{R,Type2}|Rs2]) ->
[{R,merge_types(Type1, Type2)}|merge_regs_1(Rs1, Rs2)];
merge_regs_1([], []) -> [];
merge_regs_1([], [_|_]) -> [];
merge_regs_1([_|_], []) -> [].
merge_types(T, T) -> T;
merge_types(initialized=I, _) -> I;
merge_types(_, initialized=I) -> I;
merge_types({tuple,Same}=T, {tuple,Same}) -> T;
merge_types({tuple,A}, {tuple,B}) ->
{tuple,[min(tuple_sz(A), tuple_sz(B))]};
merge_types({Type,A}, {Type,B})
when Type == atom; Type == integer; Type == float ->
if A =:= B -> {Type,A};
true -> {Type,[]}
end;
merge_types({Type,_}, number)
when Type == integer; Type == float ->
number;
merge_types(number, {Type,_})
when Type == integer; Type == float ->
number;
merge_types(bool, {atom,A}) ->
merge_bool(A);
merge_types({atom,A}, bool) ->
merge_bool(A);
merge_types(_, _) -> term.
tuple_sz([Sz]) -> Sz;
tuple_sz(Sz) -> Sz.
merge_bool([]) -> {atom,[]};
merge_bool(true) -> bool;
merge_bool(false) -> bool;
merge_bool(_) -> {atom,[]}.
verify_y_init(#vst{current=#st{numy=none}}) -> ok;
verify_y_init(#vst{current=#st{numy=undecided}}) ->
error(unknown_size_of_stackframe);
verify_y_init(#vst{current=#st{y=Ys,numy=NumY}}) ->
verify_y_init_1(NumY, Ys).
verify_y_init_1(0, _) -> ok;
verify_y_init_1(N, Ys) ->
Y = N-1,
case gb_trees:is_defined(Y, Ys) of
false -> error({{y,Y},not_initialized});
true -> verify_y_init_1(Y, Ys)
end.
verify_live(0, #vst{}) -> ok;
verify_live(N, #vst{current=#st{x=Xs}}) ->
verify_live_1(N, Xs).
verify_live_1(0, _) -> ok;
verify_live_1(N, Xs) ->
X = N-1,
case gb_trees:is_defined(X, Xs) of
false -> error({{x,X},not_live});
true -> verify_live_1(X, Xs)
end.
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.
bif_type('-', Src, Vst) ->
arith_type(Src, Vst);
bif_type('+', Src, Vst) ->
arith_type(Src, Vst);
bif_type('*', Src, Vst) ->
arith_type(Src, Vst);
bif_type(abs, [Num], Vst) ->
case get_type(Num, Vst) of
{float,_}=T -> T;
{integer,_}=T -> T;
_ -> number
end;
bif_type(float, _, _) -> {float,[]};
bif_type('/', _, _) -> {float,[]};
%% Integer operations.
bif_type('div', [_,_], _) -> {integer,[]};
bif_type('rem', [_,_], _) -> {integer,[]};
bif_type(length, [_], _) -> {integer,[]};
bif_type(size, [_], _) -> {integer,[]};
bif_type(trunc, [_], _) -> {integer,[]};
bif_type(round, [_], _) -> {integer,[]};
bif_type('band', [_,_], _) -> {integer,[]};
bif_type('bor', [_,_], _) -> {integer,[]};
bif_type('bxor', [_,_], _) -> {integer,[]};
bif_type('bnot', [_], _) -> {integer,[]};
bif_type('bsl', [_,_], _) -> {integer,[]};
bif_type('bsr', [_,_], _) -> {integer,[]};
%% Booleans.
bif_type('==', [_,_], _) -> bool;
bif_type('/=', [_,_], _) -> bool;
bif_type('=<', [_,_], _) -> bool;
bif_type('<', [_,_], _) -> bool;
bif_type('>=', [_,_], _) -> bool;
bif_type('>', [_,_], _) -> bool;
bif_type('=:=', [_,_], _) -> bool;
bif_type('=/=', [_,_], _) -> bool;
bif_type('not', [_], _) -> bool;
bif_type('and', [_,_], _) -> bool;
bif_type('or', [_,_], _) -> bool;
bif_type('xor', [_,_], _) -> bool;
bif_type(is_atom, [_], _) -> bool;
bif_type(is_boolean, [_], _) -> bool;
bif_type(is_binary, [_], _) -> bool;
bif_type(is_constant, [_], _) -> bool;
bif_type(is_float, [_], _) -> bool;
bif_type(is_function, [_], _) -> bool;
bif_type(is_integer, [_], _) -> bool;
bif_type(is_list, [_], _) -> bool;
bif_type(is_number, [_], _) -> bool;
bif_type(is_pid, [_], _) -> bool;
bif_type(is_port, [_], _) -> bool;
bif_type(is_reference, [_], _) -> bool;
bif_type(is_tuple, [_], _) -> bool;
%% Misc.
bif_type(node, [], _) -> {atom,[]};
bif_type(node, [_], _) -> {atom,[]};
bif_type(hd, [_], _) -> term;
bif_type(tl, [_], _) -> term;
bif_type(get, [_], _) -> term;
bif_type(raise, [_,_], _) -> exception;
bif_type(_, _, _) -> term.
arith_type([A,B], Vst) ->
case {get_type(A, Vst),get_type(B, Vst)} of
{{float,_},_} -> {float,[]};
{_,{float,_}} -> {float,[]};
{_,_} -> number
end;
arith_type(_, _) -> number.
return_type({extfunc,M,F,A}, Vst) ->
return_type_1(M, F, A, Vst).
return_type_1(erlang, setelement, 3, Vst) ->
Tuple = {x,1},
TupleType =
case get_type(Tuple, Vst) of
{tuple,_}=TT -> TT;
_ -> {tuple,[0]}
end,
case get_type({x,0}, Vst) of
{integer,[]} -> TupleType;
{integer,I} -> upgrade_type({tuple,[I]}, TupleType);
_ -> TupleType
end;
return_type_1(erlang, F, A, _) ->
return_type_erl(F, A);
return_type_1(math, F, A, _) ->
return_type_math(F, A);
return_type_1(_, _, _, _) -> term.
return_type_erl(exit, 1) -> exception;
return_type_erl(throw, 1) -> exception;
return_type_erl(fault, 1) -> exception;
return_type_erl(fault, 2) -> exception;
return_type_erl(error, 1) -> exception;
return_type_erl(error, 2) -> exception;
return_type_erl(_, _) -> term.
return_type_math(cos, 1) -> {float,[]};
return_type_math(cosh, 1) -> {float,[]};
return_type_math(sin, 1) -> {float,[]};
return_type_math(sinh, 1) -> {float,[]};
return_type_math(tan, 1) -> {float,[]};
return_type_math(tanh, 1) -> {float,[]};
return_type_math(acos, 1) -> {float,[]};
return_type_math(acosh, 1) -> {float,[]};
return_type_math(asin, 1) -> {float,[]};
return_type_math(asinh, 1) -> {float,[]};
return_type_math(atan, 1) -> {float,[]};
return_type_math(atanh, 1) -> {float,[]};
return_type_math(erf, 1) -> {float,[]};
return_type_math(erfc, 1) -> {float,[]};
return_type_math(exp, 1) -> {float,[]};
return_type_math(log, 1) -> {float,[]};
return_type_math(log10, 1) -> {float,[]};
return_type_math(sqrt, 1) -> {float,[]};
return_type_math(atan2, 2) -> {float,[]};
return_type_math(pow, 2) -> {float,[]};
return_type_math(pi, 0) -> {float,[]};
return_type_math(_, _) -> term.
min(A, B) when is_integer(A), is_integer(B), A < B -> A;
min(A, B) when is_integer(A), is_integer(B) -> B.
max(A, B) when is_integer(A), is_integer(B), A > B -> A;
max(A, B) when is_integer(A), is_integer(B) -> B.
gb_trees_from_list(L) -> gb_trees:from_orddict(orddict:from_list(L)).
-ifdef(DEBUG).
error(Error) -> exit(Error).
-else.
error(Error) -> throw(Error).
-endif.
