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Change in the handling of 'L->top' when calling metamethods

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Instead of updating 'L->top' in every place that may call a
metamethod, the metamethod functions themselves (luaT_trybinTM and
luaT_callorderTM) correct the top. (When calling metamethods from
the C API, however, the callers must preserve 'L->top'.)
This commit is contained in:
Roberto Ierusalimschy
2019-07-26 14:59:39 -03:00
parent e70f275f32
commit b80077b8f3
10 changed files with 75 additions and 29 deletions
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44
lvm.c
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@@ -515,8 +515,11 @@ int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
}
if (tm == NULL) /* no TM? */
return 0; /* objects are different */
luaT_callTMres(L, tm, t1, t2, L->top); /* call TM */
return !l_isfalse(s2v(L->top));
else {
L->top = L->ci->top;
luaT_callTMres(L, tm, t1, t2, L->top); /* call TM */
return !l_isfalse(s2v(L->top));
}
}
@@ -548,7 +551,7 @@ void luaV_concat (lua_State *L, int total) {
int n = 2; /* number of elements handled in this pass (at least 2) */
if (!(ttisstring(s2v(top - 2)) || cvt2str(s2v(top - 2))) ||
!tostring(L, s2v(top - 1)))
luaT_trybinTM(L, s2v(top - 2), s2v(top - 1), top - 2, TM_CONCAT);
luaT_tryconcatTM(L);
else if (isemptystr(s2v(top - 1))) /* second operand is empty? */
cast_void(tostring(L, s2v(top - 2))); /* result is first operand */
else if (isemptystr(s2v(top - 2))) { /* first operand is empty string? */
@@ -747,7 +750,7 @@ void luaV_finishOp (lua_State *L) {
break;
}
case OP_CONCAT: {
StkId top = L->top - 1; /* top when 'luaT_trybinTM' was called */
StkId top = L->top - 1; /* top when 'luaT_tryconcatTM' was called */
int a = GETARG_A(inst); /* first element to concatenate */
int total = cast_int(top - 1 - (base + a)); /* yet to concatenate */
setobjs2s(L, top - 2, top); /* put TM result in proper position */
@@ -801,7 +804,7 @@ void luaV_finishOp (lua_State *L) {
setfltvalue(s2v(ra), fop(L, nb, fimm)); \
} \
else \
Protect(luaT_trybiniTM(L, v1, imm, flip, ra, tm)); }
ProtectNT(luaT_trybiniTM(L, v1, imm, flip, ra, tm)); }
/*
@@ -836,7 +839,7 @@ void luaV_finishOp (lua_State *L) {
setfltvalue(s2v(ra), fop(L, n1, n2)); \
} \
else \
Protect(luaT_trybinTM(L, v1, v2, ra, tm)); }
ProtectNT(luaT_trybinTM(L, v1, v2, ra, tm)); }
/*
@@ -877,7 +880,7 @@ void luaV_finishOp (lua_State *L) {
setfltvalue(s2v(ra), fop(L, n1, n2)); \
} \
else \
Protect(luaT_trybinassocTM(L, v1, v2, ra, flip, tm)); } }
ProtectNT(luaT_trybinassocTM(L, v1, v2, ra, flip, tm)); } }
/*
@@ -891,7 +894,7 @@ void luaV_finishOp (lua_State *L) {
setfltvalue(s2v(ra), fop(L, n1, n2)); \
} \
else \
Protect(luaT_trybinTM(L, v1, v2, ra, tm)); }
ProtectNT(luaT_trybinTM(L, v1, v2, ra, tm)); }
/*
@@ -906,7 +909,7 @@ void luaV_finishOp (lua_State *L) {
setivalue(s2v(ra), op(L, i1, i2)); \
} \
else \
Protect(luaT_trybiniTM(L, v1, i2, TESTARG_k(i), ra, tm)); }
ProtectNT(luaT_trybiniTM(L, v1, i2, TESTARG_k(i), ra, tm)); }
/*
@@ -920,7 +923,7 @@ void luaV_finishOp (lua_State *L) {
setivalue(s2v(ra), op(L, i1, i2)); \
} \
else \
Protect(luaT_trybinTM(L, v1, v2, ra, tm)); }
ProtectNT(luaT_trybinTM(L, v1, v2, ra, tm)); }
/*
@@ -937,7 +940,7 @@ void luaV_finishOp (lua_State *L) {
else if (ttisnumber(s2v(ra)) && ttisnumber(rb)) \
cond = opf(s2v(ra), rb); \
else \
Protect(cond = other(L, s2v(ra), rb)); \
ProtectNT(cond = other(L, s2v(ra), rb)); \
docondjump(); }
@@ -956,7 +959,7 @@ void luaV_finishOp (lua_State *L) {
} \
else { \
int isf = GETARG_C(i); \
Protect(cond = luaT_callorderiTM(L, s2v(ra), im, inv, isf, tm)); \
ProtectNT(cond = luaT_callorderiTM(L, s2v(ra), im, inv, isf, tm)); \
} \
docondjump(); }
@@ -1094,7 +1097,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmfetch();
lua_assert(base == ci->func + 1);
lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
lua_assert(ci->top < L->stack + L->stacksize);
/* invalidate top for instructions not expecting it */
lua_assert(isIT(i) || (L->top = base));
vmdispatch (GET_OPCODE(i)) {
vmcase(OP_MOVE) {
setobjs2s(L, ra, RB(i));
@@ -1359,7 +1363,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
if (TESTARG_k(i)) {
ic = -ic; ev = TM_SHL;
}
Protect(luaT_trybiniTM(L, rb, ic, 0, ra, ev));
ProtectNT(luaT_trybiniTM(L, rb, ic, 0, ra, ev));
}
vmbreak;
}
@@ -1371,7 +1375,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
setivalue(s2v(ra), luaV_shiftl(ic, ib));
}
else
Protect(luaT_trybiniTM(L, rb, ic, 1, ra, TM_SHL));
ProtectNT(luaT_trybiniTM(L, rb, ic, 1, ra, TM_SHL));
vmbreak;
}
vmcase(OP_ADD) {
@@ -1422,7 +1426,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
setivalue(s2v(ra), luaV_shiftl(ib, -ic));
}
else
Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHR));
ProtectNT(luaT_trybinTM(L, rb, rc, ra, TM_SHR));
vmbreak;
}
vmcase(OP_SHL) {
@@ -1433,7 +1437,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
setivalue(s2v(ra), luaV_shiftl(ib, ic));
}
else
Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHL));
ProtectNT(luaT_trybinTM(L, rb, rc, ra, TM_SHL));
vmbreak;
}
vmcase(OP_UNM) {
@@ -1447,7 +1451,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
setfltvalue(s2v(ra), luai_numunm(L, nb));
}
else
Protect(luaT_trybinTM(L, rb, rb, ra, TM_UNM));
ProtectNT(luaT_trybinTM(L, rb, rb, ra, TM_UNM));
vmbreak;
}
vmcase(OP_BNOT) {
@@ -1457,7 +1461,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
setivalue(s2v(ra), intop(^, ~l_castS2U(0), ib));
}
else
Protect(luaT_trybinTM(L, rb, rb, ra, TM_BNOT));
ProtectNT(luaT_trybinTM(L, rb, rb, ra, TM_BNOT));
vmbreak;
}
vmcase(OP_NOT) {
@@ -1493,7 +1497,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmcase(OP_EQ) {
int cond;
TValue *rb = vRB(i);
Protect(cond = luaV_equalobj(L, s2v(ra), rb));
ProtectNT(cond = luaV_equalobj(L, s2v(ra), rb));
docondjump();
vmbreak;
}