static const char *getobjname (Proto *p, int lastpc, int reg,
const char **name) {
int pc;
*name = luaF_getlocalname(p, reg + 1, lastpc);
if (*name) /* is a local? */
return "local";
/* else try symbolic execution */
pc = findsetreg(p, lastpc, reg);
if (pc != -1) { /* could find instruction? */
Instruction i = p->code[pc];
OpCode op = GET_OPCODE(i);
switch (op) {
case OP_MOVE: {
int b = GETARG_B(i); /* move from 'b' to 'a' */
if (b < GETARG_A(i))
return getobjname(p, pc, b, name); /* get name for 'b' */
break;
}
case OP_GETTABUP:
case OP_GETTABLE: {
int k = GETARG_C(i); /* key index */
int t = GETARG_B(i); /* table index */
const char *vn = (op == OP_GETTABLE) /* name of indexed variable */
? luaF_getlocalname(p, t + 1, pc)
: upvalname(p, t);
kname(p, pc, k, name);
return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
}
case OP_GETUPVAL: {
*name = upvalname(p, GETARG_B(i));
return "upvalue";
}
case OP_LOADK:
case OP_LOADKX: {
int b = (op == OP_LOADK) ? GETARG_Bx(i)
: GETARG_Ax(p->code[pc + 1]);
if (ttisstring(&p->k[b])) {
*name = svalue(&p->k[b]);
return "constant";
}
break;
}
case OP_SELF: {
int k = GETARG_C(i); /* key index */
kname(p, pc, k, name);
return "method";
}
default:
break; /* go through to return NULL */
}
}
return NULL; /* could not find reasonable name */
}
static const char *getupvalname (CallInfo *ci, const TValue *o,
const char **name) {
LClosure *c = ci_func(ci);
int i;
for (i = 0; i < c->nupvalues; i++) {
if (c->upvals[i]->v == o) {
*name = upvalname(c->p, i);
return "upvalue";
}
}
return NULL;
}
