/*
** try to find last instruction before 'lastpc' that modified register 'reg'
*/
static int findsetreg (Proto *p, int lastpc, int reg) {
int pc;
int setreg = -1; /* keep last instruction that changed 'reg' */
int jmptarget = 0; /* any code before this address is conditional */
for (pc = 0; pc < lastpc; pc++) {
Instruction i = p->code[pc];
OpCode op = GET_OPCODE(i);
int a = GETARG_A(i);
switch (op) {
case OP_LOADNIL: {
int b = GETARG_B(i);
if (a <= reg && reg <= a + b) /* set registers from 'a' to 'a+b' */
setreg = filterpc(pc, jmptarget);
break;
}
case OP_TFORCALL: {
if (reg >= a + 2) /* affect all regs above its base */
setreg = filterpc(pc, jmptarget);
break;
}
case OP_CALL:
case OP_TAILCALL: {
if (reg >= a) /* affect all registers above base */
setreg = filterpc(pc, jmptarget);
break;
}
case OP_JMP: {
int b = GETARG_sBx(i);
int dest = pc + 1 + b;
/* jump is forward and do not skip `lastpc'? */
if (pc < dest && dest <= lastpc) {
if (dest > jmptarget)
jmptarget = dest; /* update 'jmptarget' */
}
break;
}
case OP_TEST: {
if (reg == a) /* jumped code can change 'a' */
setreg = filterpc(pc, jmptarget);
break;
}
default:
if (testAMode(op) && reg == a) /* any instruction that set A */
setreg = filterpc(pc, jmptarget);
break;
}
}
return setreg;
}
/*
** try to find last instruction before 'lastpc' that modified register 'reg'
*/
static int findsetreg (Proto *p, int lastpc, int reg) {
int pc;
int setreg = -1; /* keep last instruction that changed 'reg' */
for (pc = 0; pc < lastpc; pc++) {
Instruction i = p->code[pc];
OpCode op = GET_OPCODE(i);
int a = GETARG_A(i);
switch (op) {
case OP_LOADNIL: {
int b = GETARG_B(i);
if (a <= reg && reg <= a + b) /* set registers from 'a' to 'a+b' */
setreg = pc;
break;
}
case OP_TFORCALL: {
if (reg >= a + 2) setreg = pc; /* affect all regs above its base */
break;
}
case OP_CALL:
case OP_TAILCALL: {
if (reg >= a) setreg = pc; /* affect all registers above base */
break;
}
case OP_JMP: {
int b = GETARG_sBx(i);
int dest = pc + 1 + b;
/* jump is forward and do not skip `lastpc'? */
if (pc < dest && dest <= lastpc)
pc += b; /* do the jump */
break;
}
case OP_TEST: {
if (reg == a) setreg = pc; /* jumped code can change 'a' */
break;
}
default:
if (testAMode(op) && reg == a) /* any instruction that set A */
setreg = pc;
break;
}
}
return setreg;
}
static Instruction symbexec(const Proto* pt, int lastpc, int reg)
{
int pc;
int last; /* stores position of last instruction that changed `reg' */
last = pt->sizecode - 1; /* points to final return (a `neutral' instruction) */
check(precheck(pt));
for (pc = 0; pc < lastpc; pc++)
{
Instruction i = pt->code[pc];
OpCode op = GET_OPCODE(i);
int a = GETARG_A(i);
int b = 0;
int c = 0;
check(op < NUM_OPCODES);
checkreg(pt, a);
switch (getOpMode(op))
{
case iABC:
{
b = GETARG_B(i);
c = GETARG_C(i);
check(checkArgMode(pt, b, getBMode(op)));
check(checkArgMode(pt, c, getCMode(op)));
break;
}
case iABx:
{
b = GETARG_Bx(i);
if (getBMode(op) == OpArgK) check(b < pt->sizek);
break;
}
case iAsBx:
{
b = GETARG_sBx(i);
if (getBMode(op) == OpArgR)
{
int dest = pc + 1 + b;
check(0 <= dest && dest < pt->sizecode);
if (dest > 0)
{
int j;
/* check that it does not jump to a setlist count; this
is tricky, because the count from a previous setlist may
have the same value of an invalid setlist; so, we must
go all the way back to the first of them (if any) */
for (j = 0; j < dest; j++)
{
Instruction d = pt->code[dest - 1 - j];
if (!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0)) break;
}
/* if 'j' is even, previous value is not a setlist (even if
it looks like one) */
check((j & 1) == 0);
}
}
break;
}
}
if (testAMode(op))
{
if (a == reg) last = pc; /* change register `a' */
}
if (testTMode(op))
{
check(pc + 2 < pt->sizecode); /* check skip */
check(GET_OPCODE(pt->code[pc + 1]) == OP_JMP);
}
switch (op)
{
case OP_LOADBOOL:
{
if (c == 1) /* does it jump? */
{
check(pc + 2 < pt->sizecode); /* check its jump */
check(GET_OPCODE(pt->code[pc + 1]) != OP_SETLIST ||
GETARG_C(pt->code[pc + 1]) != 0);
}
break;
}
case OP_LOADNIL:
{
if (a <= reg && reg <= b)
last = pc; /* set registers from `a' to `b' */
break;
}
case OP_GETUPVAL:
case OP_SETUPVAL:
{
check(b < pt->nups);
break;
}
case OP_GETGLOBAL:
case OP_SETGLOBAL:
{
check(ttisstring(&pt->k[b]));
break;
}
case OP_SELF:
{
checkreg(pt, a + 1);
if (reg == a + 1) last = pc;
break;
}
case OP_CONCAT:
{
check(b < c); /* at least two operands */
break;
}
case OP_TFORLOOP:
{
check(c >= 1); /* at least one result (control variable) */
checkreg(pt, a + 2 + c); /* space for results */
if (reg >= a + 2) last = pc; /* affect all regs above its base */
break;
}
case OP_FORLOOP:
case OP_FORPREP:
checkreg(pt, a + 3);
/* go through */
case OP_JMP:
{
int dest = pc + 1 + b;
/* not full check and jump is forward and do not skip `lastpc'? */
if (reg != NO_REG && pc < dest && dest <= lastpc)
pc += b; /* do the jump */
break;
}
case OP_CALL:
case OP_TAILCALL:
{
if (b != 0)
{
checkreg(pt, a + b - 1);
}
c--; /* c = num. returns */
if (c == LUA_MULTRET)
{
check(checkopenop(pt, pc));
}
else if (c != 0)
checkreg(pt, a + c - 1);
if (reg >= a) last = pc; /* affect all registers above base */
break;
}
case OP_RETURN:
{
b--; /* b = num. returns */
if (b > 0) checkreg(pt, a + b - 1);
break;
}
case OP_SETLIST:
{
if (b > 0) checkreg(pt, a + b);
if (c == 0)
{
pc++;
check(pc < pt->sizecode - 1);
}
break;
}
case OP_CLOSURE:
{
int nup, j;
check(b < pt->sizep);
nup = pt->p[b]->nups;
check(pc + nup < pt->sizecode);
for (j = 1; j <= nup; j++)
{
OpCode op1 = GET_OPCODE(pt->code[pc + j]);
check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
}
if (reg != NO_REG) /* tracing? */
pc += nup; /* do not 'execute' these pseudo-instructions */
break;
}
case OP_VARARG:
{
check((pt->is_vararg & VARARG_ISVARARG) &&
!(pt->is_vararg & VARARG_NEEDSARG));
b--;
if (b == LUA_MULTRET) check(checkopenop(pt, pc));
checkreg(pt, a + b - 1);
break;
}
default:
break;
}
}
return pt->code[last];
}
static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
int pc;
int last; /* stores position of last instruction that changed `reg' */
last = pt->sizecode-1; /* points to final return (a `neutral' instruction) */
check(precheck(pt));
for (pc = 0; pc < lastpc; pc++) {
Instruction i = pt->code[pc];
OpCode op = GET_OPCODE(i);
int a = GETARG_A(i);
int b = 0;
int c = 0;
check(op < NUM_OPCODES);
checkreg(pt, a);
switch (getOpMode(op)) {
case iABC: {
b = GETARG_B(i);
c = GETARG_C(i);
check(checkArgMode(pt, b, getBMode(op)));
check(checkArgMode(pt, c, getCMode(op)));
break;
}
case iABx: {
b = GETARG_Bx(i);
if (getBMode(op) == OpArgK) check(b < pt->sizek);
break;
}
case iAsBx: {
b = GETARG_sBx(i);
if (getBMode(op) == OpArgR) {
int dest = pc+1+b;
check(0 <= dest && dest < pt->sizecode);
if (dest > 0) {
/* cannot jump to a setlist count */
Instruction d = pt->code[dest-1];
check(!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0));
}
}
break;
}
}
if (testAMode(op)) {
if (a == reg) last = pc; /* change register `a' */
}
if (testTMode(op)) {
check(pc+2 < pt->sizecode); /* check skip */
check(GET_OPCODE(pt->code[pc+1]) == OP_JMP);
}
switch (op) {
case OP_LOADBOOL: {
check(c == 0 || pc+2 < pt->sizecode); /* check its jump */
break;
}
case OP_LOADNIL: {
if (a <= reg && reg <= b)
last = pc; /* set registers from `a' to `b' */
break;
}
case OP_GETUPVAL:
case OP_SETUPVAL: {
check(b < pt->nups);
break;
}
case OP_GETGLOBAL:
case OP_SETGLOBAL: {
check(ttisstring(&pt->k[b]));
break;
}
case OP_SELF: {
checkreg(pt, a+1);
if (reg == a+1) last = pc;
break;
}
case OP_CONCAT: {
check(b < c); /* at least two operands */
break;
}
case OP_TFORLOOP: {
check(c >= 1); /* at least one result (control variable) */
checkreg(pt, a+2+c); /* space for results */
if (reg >= a+2) last = pc; /* affect all regs above its base */
break;
}
case OP_FORLOOP:
case OP_FORPREP:
checkreg(pt, a+3);
/* go through */
case OP_JMP: {
int dest = pc+1+b;
/* not full check and jump is forward and do not skip `lastpc'? */
if (reg != NO_REG && pc < dest && dest <= lastpc)
pc += b; /* do the jump */
break;
}
case OP_CALL:
case OP_TAILCALL: {
if (b != 0) {
checkreg(pt, a+b-1);
}
c--; /* c = num. returns */
if (c == LUA_MULTRET) {
check(checkopenop(pt, pc));
}
else if (c != 0)
checkreg(pt, a+c-1);
if (reg >= a) last = pc; /* affect all registers above base */
break;
}
case OP_RETURN: {
b--; /* b = num. returns */
if (b > 0) checkreg(pt, a+b-1);
break;
}
case OP_SETLIST: {
if (b > 0) checkreg(pt, a + b);
if (c == 0) pc++;
break;
}
case OP_CLOSURE: {
int nup;
check(b < pt->sizep);
nup = pt->p[b]->nups;
check(pc + nup < pt->sizecode);
for (; nup>0; nup--) {
OpCode op1 = GET_OPCODE(pt->code[pc+nup]);
check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
}
break;
}
case OP_VARARG: {
check((pt->is_vararg & VARARG_ISVARARG) &&
!(pt->is_vararg & VARARG_NEEDSARG));
b--;
if (b == LUA_MULTRET) check(checkopenop(pt, pc));
checkreg(pt, a+b-1);
break;
}
default: break;
}
}
return pt->code[last];
}