private static bool PatchTestReg(FuncState fs, int node, int reg)
{
InstructionPtr pi = GetJumpControl(fs, node);
if (pi.Value.GET_OPCODE() != OpCode.OP_TESTSET)
{
return(false); // cannot patch other instructions
}
if (reg != NO_REG && reg != pi.Value.GETARG_B())
{
pi.Value = pi.Value.SETARG_A(reg);
}
else
{
pi.Value = Instruction.CreateABC(OpCode.OP_TEST,
pi.Value.GETARG_B(), 0, pi.Value.GETARG_C());
}
return(true);
}
public static void PatchClose( FuncState fs, int list, int level )
{
level++; // argument is +1 to reserve 0 as non-op
while( list != NO_JUMP )
{
int next = GetJump( fs, list );
var pi = new InstructionPtr( fs.Proto.Code, list );;
Utl.Assert( pi.Value.GET_OPCODE() == OpCode.OP_JMP &&
( pi.Value.GETARG_A() == 0 ||
pi.Value.GETARG_A() >= level ) );
pi.Value = pi.Value.SETARG_A( level );
list = next;
}
}
private static InstructionPtr GetJumpControl( FuncState fs, int pc )
{
InstructionPtr pi = new InstructionPtr( fs.Proto.Code, pc );
if( pc >= 1 && TestTMode( (pi-1).Value.GET_OPCODE() ))
return (pi-1);
else
return pi;
}
public static void CodeNil( FuncState fs, int from, int n )
{
int l = from + n - 1; // last register to set nil
if( fs.Pc > fs.LastTarget ) // no jumps to current position?
{
var previous = new InstructionPtr( fs.Proto.Code, fs.Pc-1 );
if( previous.Value.GET_OPCODE() == OpCode.OP_LOADNIL )
{
int pfrom = previous.Value.GETARG_A();
int pl = pfrom + previous.Value.GETARG_B();
// can connect both?
if( (pfrom <= from && from <= pl + 1) ||
(from <= pfrom && pfrom <= l + 1))
{
if( pfrom < from ) from = pfrom; // from=min(from,pfrom)
if( pl > l ) l = pl; // l=max(l,pl)
previous.Value = previous.Value.SETARG_A( from );
previous.Value = previous.Value.SETARG_B( l - from );
return;
}
}
// else go through
}
// else no optimization
CodeABC( fs, OpCode.OP_LOADNIL, from, n-1, 0 );
}
public static int pcRel(InstructionPtr pc, Proto p)
{
debug_assert(pc.codes == p.code);
return(pc.pc - 1);
}