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keep control of stack top in Lua functions concentrated in 'luaV_execute'

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This commit is contained in:
Roberto Ierusalimschy
2017-12-28 13:42:57 -02:00
parent 8691612f01
commit cf7eff45f3
4 changed files with 40 additions and 48 deletions
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46
lvm.c
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@@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 2.328 2017/12/20 14:58:05 roberto Exp roberto $
** $Id: lvm.c,v 2.329 2017/12/22 14:16:46 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -464,8 +464,6 @@ int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
}
if (tm == NULL) /* no TM? */
return 0; /* objects are different */
if (isLuacode(L->ci))
L->top = L->ci->top; /* prepare top */
luaT_callTMres(L, tm, t1, t2, L->top); /* call TM */
return !l_isfalse(s2v(L->top));
}
@@ -780,20 +778,29 @@ void luaV_finishOp (lua_State *L) {
#define donextjump(ci) { i = *pc; dojump(ci, i, 1); }
/*
** Whenever code can raise errors (including memory errors), the global
** 'pc' must be correct to report occasional errors.
** Correct global 'pc'.
*/
#define savepc(L) (ci->u.l.savedpc = pc)
/*
** Whenever code can raise errors, the global 'pc' and the global
** 'top' must be correct to report occasional errors.
*/
#define savestate(L,ci) (savepc(L), L->top = ci->top)
/*
** Protect code that, in general, can raise errors, reallocate the
** stack, and change the hooks.
*/
#define Protect(exp) (savepc(L), (exp), updatetrap(ci))
#define Protect(exp) (savestate(L,ci), (exp), updatetrap(ci))
/* special version that does not change the top */
#define ProtectNT(exp) (savepc(L), (exp), updatetrap(ci))
/*
** Protect code that will return.
** Protect code that will finish the loop (returns).
*/
#define halfProtect(exp) (savepc(L), (exp))
@@ -842,6 +849,7 @@ 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);
vmdispatch (GET_OPCODE(i)) {
vmcase(OP_MOVE) {
setobjs2s(L, ra, RB(i));
@@ -1000,10 +1008,11 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
int b = GETARG_B(i);
int c = GETARG_C(i);
Table *t;
t = luaH_new(L);
L->top = ci->top; /* correct top in case of GC */
t = luaH_new(L); /* memory allocation */
sethvalue2s(L, ra, t);
if (b != 0 || c != 0)
luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c));
luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c)); /* idem */
checkGC(L, ra + 1);
vmbreak;
}
@@ -1371,7 +1380,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
int c = GETARG_C(i);
StkId rb;
L->top = base + c + 1; /* mark the end of concat operands */
Protect(luaV_concat(L, c - b + 1));
ProtectNT(luaV_concat(L, c - b + 1));
if (trap) { /* 'luaV_concat' may move the stack */
updatebase(ci);
ra = RA(i);
@@ -1481,7 +1490,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
if (b != 0) /* fixed number of arguments? */
L->top = ra + b; /* top signals number of arguments */
/* else previous instruction set top */
Protect(luaD_call(L, ra, nresults));
ProtectNT(luaD_call(L, ra, nresults));
vmbreak;
}
vmcase(OP_TAILCALL) {
@@ -1493,12 +1502,12 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
if (!ttisfunction(vra)) { /* not a function? */
/* try to get '__call' metamethod */
Protect(ra = luaD_tryfuncTM(L, ra));
ProtectNT(ra = luaD_tryfuncTM(L, ra));
vra = s2v(ra);
b++; /* there is now one extra argument */
}
if (!ttisLclosure(vra)) { /* C function? */
Protect(luaD_call(L, ra, LUA_MULTRET)); /* call it */
ProtectNT(luaD_call(L, ra, LUA_MULTRET)); /* call it */
/* next instruction will do the return */
}
else { /* tail call */
@@ -1568,7 +1577,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
lua_Integer ilimit, initv;
int stopnow;
if (!forlimit(plimit, &ilimit, 1, &stopnow)) {
savepc(L); /* for the error message */
savestate(L, ci); /* for the error message */
luaG_runerror(L, "'for' limit must be a number");
}
initv = (stopnow ? 0 : ivalue(init));
@@ -1618,7 +1627,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
}
else { /* try making all values floats */
lua_Number ninit; lua_Number nlimit; lua_Number nstep;
savepc(L); /* in case of errors */
savestate(L, ci); /* in case of errors */
if (!tonumber(plimit, &nlimit))
luaG_runerror(L, "'for' limit must be a number");
setfltvalue(plimit, nlimit);
@@ -1659,7 +1668,10 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
int c = GETARG_C(i);
unsigned int last;
Table *h;
if (n == 0) n = cast_int(L->top - ra) - 1;
if (n == 0)
n = cast_int(L->top - ra) - 1;
else
L->top = ci->top; /* correct top in case of GC */
if (c == 0) {
c = GETARG_Ax(*pc); pc++;
}
@@ -1679,7 +1691,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
Proto *p = cl->p->p[GETARG_Bx(i)];
LClosure *ncl = getcached(p, cl->upvals, base); /* cached closure */
if (ncl == NULL) { /* no match? */
savepc(L); /* in case of allocation errors */
savestate(L, ci); /* in case of allocation errors */
pushclosure(L, p, cl->upvals, base, ra); /* create a new one */
}
else