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Towards "to closed" local variables

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Start of the implementation of "scoped variables" or "to be closed"
variables, local variables whose '__close' (or themselves) are called
when they go out of scope. This commit implements the syntax, the
opcode, and the creation of the corresponding upvalue, but it still
does not call the finalizations when the variable goes out of scope
(the most important part).

Currently, the syntax is 'local scoped name = exp', but that will
probably change.
This commit is contained in:
Roberto Ierusalimschy 2018-10-08 10:42:07 -03:00
parent b114c7d487
commit 4cd1f4aac0
15 changed files with 81 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
lcode.c
View File

@ -1673,13 +1673,13 @@ void luaK_finish (FuncState *fs) {
lua_assert(i == 0 || isOT(*(pc - 1)) == isIT(*pc));
switch (GET_OPCODE(*pc)) {
case OP_RETURN0: case OP_RETURN1: {
if (p->sizep == 0 && !p->is_vararg)
if (!(fs->needclose || p->is_vararg))
break; /* no extra work */
/* else use OP_RETURN to do the extra work */
SET_OPCODE(*pc, OP_RETURN);
} /* FALLTHROUGH */
case OP_RETURN: case OP_TAILCALL: {
if (p->sizep > 0 || p->is_vararg) {
if (fs->needclose || p->is_vararg) {
SETARG_C(*pc, p->is_vararg ? p->numparams + 1 : 0);
SETARG_k(*pc, 1); /* signal that there is extra work */
}

3
ldo.c
View File

@ -91,8 +91,7 @@ struct lua_longjmp {
static void seterrorobj (lua_State *L, int errcode, StkId oldtop) {
switch (errcode) {
case LUA_ERRMEM: { /* memory error? */
TString *memerrmsg = luaS_newliteral(L, MEMERRMSG);
setsvalue2s(L, oldtop, memerrmsg); /* reuse preregistered msg. */
setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
break;
}
case LUA_ERRERR: {

4
lgc.c
View File

@ -293,7 +293,8 @@ static void reallymarkobject (global_State *g, GCObject *o) {
gray2black(o);
break;
}
case LUA_TUPVAL: {
case LUA_TUPVAL:
case LUA_TUPVALTBC: {
UpVal *uv = gco2upv(o);
if (!upisopen(uv)) /* open upvalues are kept gray */
gray2black(o);
@ -760,6 +761,7 @@ static void freeobj (lua_State *L, GCObject *o) {
luaF_freeproto(L, gco2p(o));
break;
case LUA_TUPVAL:
case LUA_TUPVALTBC:
freeupval(L, gco2upv(o));
break;
case LUA_TLCL:

1
ljumptab.h
View File

@ -74,6 +74,7 @@ static void *disptab[] = {
&&L_OP_LEN,
&&L_OP_CONCAT,
&&L_OP_CLOSE,
&&L_OP_TBC,
&&L_OP_JMP,
&&L_OP_EQ,
&&L_OP_LT,

4
lobject.h
View File

@ -588,6 +588,10 @@ typedef struct UpVal {
} UpVal;
/* variant for "To Be Closed" upvalues */
#define LUA_TUPVALTBC (LUA_TUPVAL | (1 << 4))
#define ClosureHeader \
CommonHeader; lu_byte nupvalues; GCObject *gclist

1
lopcodes.c
View File

@ -68,6 +68,7 @@ LUAI_DDEF const lu_byte luaP_opmodes[NUM_OPCODES] = {
,opmode(0, 0, 0, 1, iABC) /* OP_LEN */
,opmode(0, 0, 0, 1, iABC) /* OP_CONCAT */
,opmode(0, 0, 0, 0, iABC) /* OP_CLOSE */
,opmode(0, 0, 0, 0, iABC) /* OP_TBC */
,opmode(0, 0, 0, 0, isJ) /* OP_JMP */
,opmode(0, 0, 1, 0, iABC) /* OP_EQ */
,opmode(0, 0, 1, 0, iABC) /* OP_LT */

1
lopcodes.h
View File

@ -251,6 +251,7 @@ OP_LEN,/* A B R(A) := length of R(B) */
OP_CONCAT,/* A B R(A) := R(A).. ... ..R(A + B - 1) */
OP_CLOSE,/* A close all upvalues >= R(A) */
OP_TBC,/* A mark variable A "to be closed" */
OP_JMP,/* k sJ pc += sJ (k is used in code generation) */
OP_EQ,/* A B if ((R(A) == R(B)) ~= k) then pc++ */
OP_LT,/* A B if ((R(A) < R(B)) ~= k) then pc++ */

1
lopnames.h
View File

@ -59,6 +59,7 @@ static const char *const opnames[] = {
"LEN",
"CONCAT",
"CLOSE",
"TBC",
"JMP",
"EQ",
"LT",

34
lparser.c
View File

@ -255,6 +255,7 @@ static void markupval (FuncState *fs, int level) {
while (bl->nactvar > level)
bl = bl->previous;
bl->upval = 1;
fs->needclose = 1;
}
@ -547,6 +548,7 @@ static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
fs->nups = 0;
fs->nlocvars = 0;
fs->nactvar = 0;
fs->needclose = 0;
fs->firstlocal = ls->dyd->actvar.n;
fs->bl = NULL;
f->source = ls->source;
@ -1509,15 +1511,16 @@ static void localfunc (LexState *ls) {
}
static void localstat (LexState *ls) {
static void commonlocalstat (LexState *ls, TString *firstvar) {
/* stat -> LOCAL NAME {',' NAME} ['=' explist] */
int nvars = 0;
int nvars = 1;
int nexps;
expdesc e;
do {
new_localvar(ls, firstvar);
while (testnext(ls, ',')) {
new_localvar(ls, str_checkname(ls));
nvars++;
} while (testnext(ls, ','));
}
if (testnext(ls, '='))
nexps = explist(ls, &e);
else {
@ -1529,6 +1532,29 @@ static void localstat (LexState *ls) {
}
static void scopedlocalstat (LexState *ls) {
FuncState *fs = ls->fs;
new_localvar(ls, str_checkname(ls));
checknext(ls, '=');
luaK_codeABC(fs, OP_TBC, fs->nactvar, 0, 0);
markupval(fs, fs->nactvar);
exp1(ls, 0);
adjustlocalvars(ls, 1);
}
static void localstat (LexState *ls) {
/* stat -> LOCAL NAME {',' NAME} ['=' explist]
| LOCAL SCOPED NAME '=' exp */
TString *firstvar = str_checkname(ls);
if (ls->t.token == TK_NAME &&
eqshrstr(firstvar, luaS_newliteral(ls->L, "scoped")))
scopedlocalstat(ls);
else
commonlocalstat(ls, firstvar);
}
static int funcname (LexState *ls, expdesc *v) {
/* funcname -> NAME {fieldsel} [':' NAME] */
int ismethod = 0;

1
lparser.h
View File

@ -133,6 +133,7 @@ typedef struct FuncState {
lu_byte nups; /* number of upvalues */
lu_byte freereg; /* first free register */
lu_byte iwthabs; /* instructions issued since last absolute line info */
lu_byte needclose; /* function needs to close upvalues when returning */
} FuncState;

3
lstate.h
View File

@ -267,7 +267,8 @@ union GCUnion {
#define gco2t(o) check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h))
#define gco2p(o) check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p))
#define gco2th(o) check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th))
#define gco2upv(o) check_exp((o)->tt == LUA_TUPVAL, &((cast_u(o))->upv))
#define gco2upv(o) \
check_exp(novariant((o)->tt) == LUA_TUPVAL, &((cast_u(o))->upv))
/*

25
ltests.c
View File

@ -357,7 +357,8 @@ static void checkrefs (global_State *g, GCObject *o) {
checkudata(g, gco2u(o));
break;
}
case LUA_TUPVAL: {
case LUA_TUPVAL:
case LUA_TUPVALTBC: {
checkvalref(g, o, gco2upv(o)->v);
break;
}
@ -522,35 +523,37 @@ int lua_checkmemory (lua_State *L) {
static char *buildop (Proto *p, int pc, char *buff) {
char *obuff = buff;
Instruction i = p->code[pc];
OpCode o = GET_OPCODE(i);
const char *name = opnames[o];
int line = luaG_getfuncline(p, pc);
int lineinfo = (p->lineinfo != NULL) ? p->lineinfo[pc] : 0;
sprintf(buff, "(%2d - %4d) %4d - ", lineinfo, line, pc);
if (lineinfo == ABSLINEINFO)
buff += sprintf(buff, "(__");
else
buff += sprintf(buff, "(%2d", lineinfo);
buff += sprintf(buff, " - %4d) %4d - ", line, pc);
switch (getOpMode(o)) {
case iABC:
sprintf(buff+strlen(buff), "%-12s%4d %4d %4d%s", name,
sprintf(buff, "%-12s%4d %4d %4d%s", name,
GETARG_A(i), GETARG_B(i), GETARG_C(i),
GETARG_k(i) ? " (k)" : "");
break;
case iABx:
sprintf(buff+strlen(buff), "%-12s%4d %4d", name, GETARG_A(i),
GETARG_Bx(i));
sprintf(buff, "%-12s%4d %4d", name, GETARG_A(i), GETARG_Bx(i));
break;
case iAsBx:
sprintf(buff+strlen(buff), "%-12s%4d %4d", name, GETARG_A(i),
GETARG_sBx(i));
sprintf(buff, "%-12s%4d %4d", name, GETARG_A(i), GETARG_sBx(i));
break;
case iAx:
sprintf(buff+strlen(buff), "%-12s%4d", name, GETARG_Ax(i));
sprintf(buff, "%-12s%4d", name, GETARG_Ax(i));
break;
case isJ:
sprintf(buff+strlen(buff), "%-12s%4d (%1d)", name, GETARG_sJ(i),
!!GETARG_m(i));
sprintf(buff, "%-12s%4d (%1d)", name, GETARG_sJ(i), !!GETARG_m(i));
break;
}
return buff;
return obuff;
}

6
lvm.c
View File

@ -1455,6 +1455,12 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
luaF_close(L, ra);
vmbreak;
}
vmcase(OP_TBC) {
UpVal *up = luaF_findupval(L, ra); /* create new upvalue */
up->tt = LUA_TUPVALTBC; /* mark it to be closed */
setnilvalue(s2v(ra)); /* intialize it with nil */
vmbreak;
}
vmcase(OP_JMP) {
dojump(ci, i, 0);
vmbreak;

6
testes/code.lua
View File

@ -64,8 +64,12 @@ end
-- some basic instructions
check(function ()
check(function () -- function does not create upvalues
(function () end){f()}
end, 'CLOSURE', 'NEWTABLE', 'GETTABUP', 'CALL', 'SETLIST', 'CALL', 'RETURN0')
check(function (x) -- function creates upvalues
(function () return x end){f()}
end, 'CLOSURE', 'NEWTABLE', 'GETTABUP', 'CALL', 'SETLIST', 'CALL', 'RETURN')

9
testes/locals.lua
View File

@ -173,6 +173,15 @@ end
assert(x==20)
-- tests for to-be-closed variables
do
local scoped x = 3
local a
local scoped y = 5
assert(x == 3 and y == 5)
end
print('OK')
return 5,f