/*
** $Id: lcode.c,v 2.62.1.1 2013/04/12 18:48:47 roberto Exp $
** Code generator for Lua
** See Copyright Notice in lua.h
*/

#include <stdlib.h>

#define lcode_c
#define LUA_CORE

#include "lua.h"

#include "lcode.h"
#include "ldebug.h"
#include "ldo.h"
#include "lgc.h"
#include "llex.h"
#include "lmem.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lparser.h"
#include "lstring.h"
#include "ltable.h"
#include "lvm.h"

#define hasjumps(e) ((e)->t != (e)->f)

static int isnumeral(expdesc *e)
{
	return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP);
}

void luaK_nil(FuncState *fs, int from, int n)
{
	Instruction *previous;
	int l = from + n - 1; /* last register to set nil */
	if (fs->pc > fs->lasttarget)
	{ /* no jumps to current position? */
		previous = &fs->f->code[fs->pc - 1];
		if (GET_OPCODE(*previous) == OP_LOADNIL)
		{
			int pfrom = GETARG_A(*previous);
			int pl = pfrom + GETARG_B(*previous);
			if ((pfrom <= from && from <= pl + 1) ||
				(from <= pfrom && pfrom <= l + 1))
			{                                   /* can connect both? */
				if (pfrom < from) from = pfrom; /* from = min(from, pfrom) */
				if (pl > l) l = pl;             /* l = max(l, pl) */
				SETARG_A(*previous, from);
				SETARG_B(*previous, l - from);
				return;
			}
		} /* else go through */
	}
	luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0); /* else no optimization */
}

int luaK_jump(FuncState *fs)
{
	int jpc = fs->jpc; /* save list of jumps to here */
	int j;
	fs->jpc = NO_JUMP;
	j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
	luaK_concat(fs, &j, jpc); /* keep them on hold */
	return j;
}

void luaK_ret(FuncState *fs, int first, int nret)
{
	luaK_codeABC(fs, OP_RETURN, first, nret + 1, 0);
}

static int condjump(FuncState *fs, OpCode op, int A, int B, int C)
{
	luaK_codeABC(fs, op, A, B, C);
	return luaK_jump(fs);
}

static void fixjump(FuncState *fs, int pc, int dest)
{
	Instruction *jmp = &fs->f->code[pc];
	int offset = dest - (pc + 1);
	lua_assert(dest != NO_JUMP);
	if (abs(offset) > MAXARG_sBx)
		luaX_syntaxerror(fs->ls, "control structure too long");
	SETARG_sBx(*jmp, offset);
}

/*
** returns current `pc' and marks it as a jump target (to avoid wrong
** optimizations with consecutive instructions not in the same basic block).
*/
int luaK_getlabel(FuncState *fs)
{
	fs->lasttarget = fs->pc;
	return fs->pc;
}

static int getjump(FuncState *fs, int pc)
{
	int offset = GETARG_sBx(fs->f->code[pc]);
	if (offset == NO_JUMP) /* point to itself represents end of list */
		return NO_JUMP;    /* end of list */
	else
		return (pc + 1) + offset; /* turn offset into absolute position */
}

static Instruction *getjumpcontrol(FuncState *fs, int pc)
{
	Instruction *pi = &fs->f->code[pc];
	if (pc >= 1 && testTMode(GET_OPCODE(*(pi - 1))))
		return pi - 1;
	else
		return pi;
}

/*
** check whether list has any jump that do not produce a value
** (or produce an inverted value)
*/
static int need_value(FuncState *fs, int list)
{
	for (; list != NO_JUMP; list = getjump(fs, list))
	{
		Instruction i = *getjumpcontrol(fs, list);
		if (GET_OPCODE(i) != OP_TESTSET) return 1;
	}
	return 0; /* not found */
}

static int patchtestreg(FuncState *fs, int node, int reg)
{
	Instruction *i = getjumpcontrol(fs, node);
	if (GET_OPCODE(*i) != OP_TESTSET)
		return 0; /* cannot patch other instructions */
	if (reg != NO_REG && reg != GETARG_B(*i))
		SETARG_A(*i, reg);
	else /* no register to put value or register already has the value */
		*i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));

	return 1;
}

static void removevalues(FuncState *fs, int list)
{
	for (; list != NO_JUMP; list = getjump(fs, list))
		patchtestreg(fs, list, NO_REG);
}

static void patchlistaux(FuncState *fs, int list, int vtarget, int reg,
						 int dtarget)
{
	while (list != NO_JUMP)
	{
		int next = getjump(fs, list);
		if (patchtestreg(fs, list, reg))
			fixjump(fs, list, vtarget);
		else
			fixjump(fs, list, dtarget); /* jump to default target */
		list = next;
	}
}

static void dischargejpc(FuncState *fs)
{
	patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
	fs->jpc = NO_JUMP;
}

void luaK_patchlist(FuncState *fs, int list, int target)
{
	if (target == fs->pc)
		luaK_patchtohere(fs, list);
	else
	{
		lua_assert(target < fs->pc);
		patchlistaux(fs, list, target, NO_REG, target);
	}
}

LUAI_FUNC void luaK_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);
		lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP &&
				   (GETARG_A(fs->f->code[list]) == 0 ||
					GETARG_A(fs->f->code[list]) >= level));
		SETARG_A(fs->f->code[list], level);
		list = next;
	}
}

void luaK_patchtohere(FuncState *fs, int list)
{
	luaK_getlabel(fs);
	luaK_concat(fs, &fs->jpc, list);
}

void luaK_concat(FuncState *fs, int *l1, int l2)
{
	if (l2 == NO_JUMP)
		return;
	else if (*l1 == NO_JUMP)
		*l1 = l2;
	else
	{
		int list = *l1;
		int next;
		while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */
			list = next;
		fixjump(fs, list, l2);
	}
}

static int luaK_code(FuncState *fs, Instruction i)
{
	Proto *f = fs->f;
	dischargejpc(fs); /* `pc' will change */
	/* put new instruction in code array */
	luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
					MAX_INT, "opcodes");
	f->code[fs->pc] = i;
	/* save corresponding line information */
	luaM_growvector(fs->ls->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
					MAX_INT, "opcodes");
	f->lineinfo[fs->pc] = fs->ls->lastline;
	return fs->pc++;
}

int luaK_codeABC(FuncState *fs, OpCode o, int a, int b, int c)
{
	lua_assert(getOpMode(o) == iABC);
	lua_assert(getBMode(o) != OpArgN || b == 0);
	lua_assert(getCMode(o) != OpArgN || c == 0);
	lua_assert(a <= MAXARG_A && b <= MAXARG_B && c <= MAXARG_C);
	return luaK_code(fs, CREATE_ABC(o, a, b, c));
}

int luaK_codeABx(FuncState *fs, OpCode o, int a, unsigned int bc)
{
	lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
	lua_assert(getCMode(o) == OpArgN);
	lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx);
	return luaK_code(fs, CREATE_ABx(o, a, bc));
}

static int codeextraarg(FuncState *fs, int a)
{
	lua_assert(a <= MAXARG_Ax);
	return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
}

int luaK_codek(FuncState *fs, int reg, int k)
{
	if (k <= MAXARG_Bx)
		return luaK_codeABx(fs, OP_LOADK, reg, k);
	else
	{
		int p = luaK_codeABx(fs, OP_LOADKX, reg, 0);
		codeextraarg(fs, k);
		return p;
	}
}

void luaK_checkstack(FuncState *fs, int n)
{
	int newstack = fs->freereg + n;
	if (newstack > fs->f->maxstacksize)
	{
		if (newstack >= MAXSTACK)
			luaX_syntaxerror(fs->ls, "function or expression too complex");
		fs->f->maxstacksize = cast_byte(newstack);
	}
}

void luaK_reserveregs(FuncState *fs, int n)
{
	luaK_checkstack(fs, n);
	fs->freereg += n;
}

static void freereg(FuncState *fs, int reg)
{
	if (!ISK(reg) && reg >= fs->nactvar)
	{
		fs->freereg--;
		lua_assert(reg == fs->freereg);
	}
}

static void freeexp(FuncState *fs, expdesc *e)
{
	if (e->k == VNONRELOC)
		freereg(fs, e->u.info);
}

static int addk(FuncState *fs, TValue *key, TValue *v)
{
	lua_State *L = fs->ls->L;
	TValue *idx = luaH_set(L, fs->h, key);
	Proto *f = fs->f;
	int k, oldsize;
	if (ttisnumber(idx))
	{
		lua_Number n = nvalue(idx);
		lua_number2int(k, n);
		if (luaV_rawequalobj(&f->k[k], v))
			return k;
		/* else may be a collision (e.g., between 0.0 and "\0\0\0\0\0\0\0\0");
       go through and create a new entry for this value */
	}
	/* constant not found; create a new entry */
	oldsize = f->sizek;
	k = fs->nk;
	/* numerical value does not need GC barrier;
     table has no metatable, so it does not need to invalidate cache */
	setnvalue(idx, cast_num(k));
	luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
	while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
	setobj(L, &f->k[k], v);
	fs->nk++;
	luaC_barrier(L, f, v);
	return k;
}

int luaK_stringK(FuncState *fs, TString *s)
{
	TValue o;
	setsvalue(fs->ls->L, &o, s);
	return addk(fs, &o, &o);
}

int luaK_numberK(FuncState *fs, lua_Number r)
{
	int n;
	lua_State *L = fs->ls->L;
	TValue o;
	setnvalue(&o, r);
	if (r == 0 || luai_numisnan(NULL, r))
	{ /* handle -0 and NaN */
		/* use raw representation as key to avoid numeric problems */
		setsvalue(L, L->top++, luaS_newlstr(L, (char *)&r, sizeof(r)));
		n = addk(fs, L->top - 1, &o);
		L->top--;
	}
	else
		n = addk(fs, &o, &o); /* regular case */
	return n;
}

static int boolK(FuncState *fs, int b)
{
	TValue o;
	setbvalue(&o, b);
	return addk(fs, &o, &o);
}

static int nilK(FuncState *fs)
{
	TValue k, v;
	setnilvalue(&v);
	/* cannot use nil as key; instead use table itself to represent nil */
	sethvalue(fs->ls->L, &k, fs->h);
	return addk(fs, &k, &v);
}

void luaK_setreturns(FuncState *fs, expdesc *e, int nresults)
{
	if (e->k == VCALL)
	{ /* expression is an open function call? */
		SETARG_C(getcode(fs, e), nresults + 1);
	}
	else if (e->k == VVARARG)
	{
		SETARG_B(getcode(fs, e), nresults + 1);
		SETARG_A(getcode(fs, e), fs->freereg);
		luaK_reserveregs(fs, 1);
	}
}

void luaK_setoneret(FuncState *fs, expdesc *e)
{
	if (e->k == VCALL)
	{ /* expression is an open function call? */
		e->k = VNONRELOC;
		e->u.info = GETARG_A(getcode(fs, e));
	}
	else if (e->k == VVARARG)
	{
		SETARG_B(getcode(fs, e), 2);
		e->k = VRELOCABLE; /* can relocate its simple result */
	}
}

void luaK_dischargevars(FuncState *fs, expdesc *e)
{
	switch (e->k)
	{
		case VLOCAL:
		{
			e->k = VNONRELOC;
			break;
		}
		case VUPVAL:
		{
			e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
			e->k = VRELOCABLE;
			break;
		}
		case VINDEXED:
		{
			OpCode op = OP_GETTABUP; /* assume 't' is in an upvalue */
			freereg(fs, e->u.ind.idx);
			if (e->u.ind.vt == VLOCAL)
			{ /* 't' is in a register? */
				freereg(fs, e->u.ind.t);
				op = OP_GETTABLE;
			}
			e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx);
			e->k = VRELOCABLE;
			break;
		}
		case VVARARG:
		case VCALL:
		{
			luaK_setoneret(fs, e);
			break;
		}
		default:
			break; /* there is one value available (somewhere) */
	}
}

static int code_label(FuncState *fs, int A, int b, int jump)
{
	luaK_getlabel(fs); /* those instructions may be jump targets */
	return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
}

static void discharge2reg(FuncState *fs, expdesc *e, int reg)
{
	luaK_dischargevars(fs, e);
	switch (e->k)
	{
		case VNIL:
		{
			luaK_nil(fs, reg, 1);
			break;
		}
		case VFALSE:
		case VTRUE:
		{
			luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
			break;
		}
		case VK:
		{
			luaK_codek(fs, reg, e->u.info);
			break;
		}
		case VKNUM:
		{
			luaK_codek(fs, reg, luaK_numberK(fs, e->u.nval));
			break;
		}
		case VRELOCABLE:
		{
			Instruction *pc = &getcode(fs, e);
			SETARG_A(*pc, reg);
			break;
		}
		case VNONRELOC:
		{
			if (reg != e->u.info)
				luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);
			break;
		}
		default:
		{
			lua_assert(e->k == VVOID || e->k == VJMP);
			return; /* nothing to do... */
		}
	}
	e->u.info = reg;
	e->k = VNONRELOC;
}

static void discharge2anyreg(FuncState *fs, expdesc *e)
{
	if (e->k != VNONRELOC)
	{
		luaK_reserveregs(fs, 1);
		discharge2reg(fs, e, fs->freereg - 1);
	}
}

static void exp2reg(FuncState *fs, expdesc *e, int reg)
{
	discharge2reg(fs, e, reg);
	if (e->k == VJMP)
		luaK_concat(fs, &e->t, e->u.info); /* put this jump in `t' list */
	if (hasjumps(e))
	{
		int final;         /* position after whole expression */
		int p_f = NO_JUMP; /* position of an eventual LOAD false */
		int p_t = NO_JUMP; /* position of an eventual LOAD true */
		if (need_value(fs, e->t) || need_value(fs, e->f))
		{
			int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
			p_f = code_label(fs, reg, 0, 1);
			p_t = code_label(fs, reg, 1, 0);
			luaK_patchtohere(fs, fj);
		}
		final = luaK_getlabel(fs);
		patchlistaux(fs, e->f, final, reg, p_f);
		patchlistaux(fs, e->t, final, reg, p_t);
	}
	e->f = e->t = NO_JUMP;
	e->u.info = reg;
	e->k = VNONRELOC;
}

void luaK_exp2nextreg(FuncState *fs, expdesc *e)
{
	luaK_dischargevars(fs, e);
	freeexp(fs, e);
	luaK_reserveregs(fs, 1);
	exp2reg(fs, e, fs->freereg - 1);
}

int luaK_exp2anyreg(FuncState *fs, expdesc *e)
{
	luaK_dischargevars(fs, e);
	if (e->k == VNONRELOC)
	{
		if (!hasjumps(e)) return e->u.info; /* exp is already in a register */
		if (e->u.info >= fs->nactvar)
		{                              /* reg. is not a local? */
			exp2reg(fs, e, e->u.info); /* put value on it */
			return e->u.info;
		}
	}
	luaK_exp2nextreg(fs, e); /* default */
	return e->u.info;
}

void luaK_exp2anyregup(FuncState *fs, expdesc *e)
{
	if (e->k != VUPVAL || hasjumps(e))
		luaK_exp2anyreg(fs, e);
}

void luaK_exp2val(FuncState *fs, expdesc *e)
{
	if (hasjumps(e))
		luaK_exp2anyreg(fs, e);
	else
		luaK_dischargevars(fs, e);
}

int luaK_exp2RK(FuncState *fs, expdesc *e)
{
	luaK_exp2val(fs, e);
	switch (e->k)
	{
		case VTRUE:
		case VFALSE:
		case VNIL:
		{
			if (fs->nk <= MAXINDEXRK)
			{ /* constant fits in RK operand? */
				e->u.info = (e->k == VNIL) ? nilK(fs) : boolK(fs, (e->k == VTRUE));
				e->k = VK;
				return RKASK(e->u.info);
			}
			else
				break;
		}
		case VKNUM:
		{
			e->u.info = luaK_numberK(fs, e->u.nval);
			e->k = VK;
			/* go through */
		}
		case VK:
		{
			if (e->u.info <= MAXINDEXRK) /* constant fits in argC? */
				return RKASK(e->u.info);
			else
				break;
		}
		default:
			break;
	}
	/* not a constant in the right range: put it in a register */
	return luaK_exp2anyreg(fs, e);
}

void luaK_storevar(FuncState *fs, expdesc *var, expdesc *ex)
{
	switch (var->k)
	{
		case VLOCAL:
		{
			freeexp(fs, ex);
			exp2reg(fs, ex, var->u.info);
			return;
		}
		case VUPVAL:
		{
			int e = luaK_exp2anyreg(fs, ex);
			luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0);
			break;
		}
		case VINDEXED:
		{
			OpCode op = (var->u.ind.vt == VLOCAL) ? OP_SETTABLE : OP_SETTABUP;
			int e = luaK_exp2RK(fs, ex);
			luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e);
			break;
		}
		default:
		{
			lua_assert(0); /* invalid var kind to store */
			break;
		}
	}
	freeexp(fs, ex);
}

void luaK_self(FuncState *fs, expdesc *e, expdesc *key)
{
	int ereg;
	luaK_exp2anyreg(fs, e);
	ereg = e->u.info; /* register where 'e' was placed */
	freeexp(fs, e);
	e->u.info = fs->freereg; /* base register for op_self */
	e->k = VNONRELOC;
	luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */
	luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key));
	freeexp(fs, key);
}

static void invertjump(FuncState *fs, expdesc *e)
{
	Instruction *pc = getjumpcontrol(fs, e->u.info);
	lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
			   GET_OPCODE(*pc) != OP_TEST);
	SETARG_A(*pc, !(GETARG_A(*pc)));
}

static int jumponcond(FuncState *fs, expdesc *e, int cond)
{
	if (e->k == VRELOCABLE)
	{
		Instruction ie = getcode(fs, e);
		if (GET_OPCODE(ie) == OP_NOT)
		{
			fs->pc--; /* remove previous OP_NOT */
			return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
		}
		/* else go through */
	}
	discharge2anyreg(fs, e);
	freeexp(fs, e);
	return condjump(fs, OP_TESTSET, NO_REG, e->u.info, cond);
}

void luaK_goiftrue(FuncState *fs, expdesc *e)
{
	int pc; /* pc of last jump */
	luaK_dischargevars(fs, e);
	switch (e->k)
	{
		case VJMP:
		{
			invertjump(fs, e);
			pc = e->u.info;
			break;
		}
		case VK:
		case VKNUM:
		case VTRUE:
		{
			pc = NO_JUMP; /* always true; do nothing */
			break;
		}
		default:
		{
			pc = jumponcond(fs, e, 0);
			break;
		}
	}
	luaK_concat(fs, &e->f, pc); /* insert last jump in `f' list */
	luaK_patchtohere(fs, e->t);
	e->t = NO_JUMP;
}

void luaK_goiffalse(FuncState *fs, expdesc *e)
{
	int pc; /* pc of last jump */
	luaK_dischargevars(fs, e);
	switch (e->k)
	{
		case VJMP:
		{
			pc = e->u.info;
			break;
		}
		case VNIL:
		case VFALSE:
		{
			pc = NO_JUMP; /* always false; do nothing */
			break;
		}
		default:
		{
			pc = jumponcond(fs, e, 1);
			break;
		}
	}
	luaK_concat(fs, &e->t, pc); /* insert last jump in `t' list */
	luaK_patchtohere(fs, e->f);
	e->f = NO_JUMP;
}

static void codenot(FuncState *fs, expdesc *e)
{
	luaK_dischargevars(fs, e);
	switch (e->k)
	{
		case VNIL:
		case VFALSE:
		{
			e->k = VTRUE;
			break;
		}
		case VK:
		case VKNUM:
		case VTRUE:
		{
			e->k = VFALSE;
			break;
		}
		case VJMP:
		{
			invertjump(fs, e);
			break;
		}
		case VRELOCABLE:
		case VNONRELOC:
		{
			discharge2anyreg(fs, e);
			freeexp(fs, e);
			e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
			e->k = VRELOCABLE;
			break;
		}
		default:
		{
			lua_assert(0); /* cannot happen */
			break;
		}
	}
	/* interchange true and false lists */
	{
		int temp = e->f;
		e->f = e->t;
		e->t = temp;
	}
	removevalues(fs, e->f);
	removevalues(fs, e->t);
}

void luaK_indexed(FuncState *fs, expdesc *t, expdesc *k)
{
	lua_assert(!hasjumps(t));
	t->u.ind.t = t->u.info;
	t->u.ind.idx = luaK_exp2RK(fs, k);
	t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL
								   : check_exp(vkisinreg(t->k), VLOCAL);
	t->k = VINDEXED;
}

static int constfolding(OpCode op, expdesc *e1, expdesc *e2)
{
	lua_Number r;
	if (!isnumeral(e1) || !isnumeral(e2)) return 0;
	if ((op == OP_DIV || op == OP_MOD) && e2->u.nval == 0)
		return 0; /* do not attempt to divide by 0 */
	r = luaO_arith(op - OP_ADD + LUA_OPADD, e1->u.nval, e2->u.nval);
	e1->u.nval = r;
	return 1;
}

static void codearith(FuncState *fs, OpCode op,
					  expdesc *e1, expdesc *e2, int line)
{
	if (constfolding(op, e1, e2))
		return;
	else
	{
		int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;
		int o1 = luaK_exp2RK(fs, e1);
		if (o1 > o2)
		{
			freeexp(fs, e1);
			freeexp(fs, e2);
		}
		else
		{
			freeexp(fs, e2);
			freeexp(fs, e1);
		}
		e1->u.info = luaK_codeABC(fs, op, 0, o1, o2);
		e1->k = VRELOCABLE;
		luaK_fixline(fs, line);
	}
}

static void codecomp(FuncState *fs, OpCode op, int cond, expdesc *e1,
					 expdesc *e2)
{
	int o1 = luaK_exp2RK(fs, e1);
	int o2 = luaK_exp2RK(fs, e2);
	freeexp(fs, e2);
	freeexp(fs, e1);
	if (cond == 0 && op != OP_EQ)
	{
		int temp; /* exchange args to replace by `<' or `<=' */
		temp = o1;
		o1 = o2;
		o2 = temp; /* o1 <==> o2 */
		cond = 1;
	}
	e1->u.info = condjump(fs, op, cond, o1, o2);
	e1->k = VJMP;
}

void luaK_prefix(FuncState *fs, UnOpr op, expdesc *e, int line)
{
	expdesc e2;
	e2.t = e2.f = NO_JUMP;
	e2.k = VKNUM;
	e2.u.nval = 0;
	switch (op)
	{
		case OPR_MINUS:
		{
			if (isnumeral(e))                             /* minus constant? */
				e->u.nval = luai_numunm(NULL, e->u.nval); /* fold it */
			else
			{
				luaK_exp2anyreg(fs, e);
				codearith(fs, OP_UNM, e, &e2, line);
			}
			break;
		}
		case OPR_NOT:
			codenot(fs, e);
			break;
		case OPR_LEN:
		{
			luaK_exp2anyreg(fs, e); /* cannot operate on constants */
			codearith(fs, OP_LEN, e, &e2, line);
			break;
		}
		default:
			lua_assert(0);
	}
}

void luaK_infix(FuncState *fs, BinOpr op, expdesc *v)
{
	switch (op)
	{
		case OPR_AND:
		{
			luaK_goiftrue(fs, v);
			break;
		}
		case OPR_OR:
		{
			luaK_goiffalse(fs, v);
			break;
		}
		case OPR_CONCAT:
		{
			luaK_exp2nextreg(fs, v); /* operand must be on the `stack' */
			break;
		}
		case OPR_ADD:
		case OPR_SUB:
		case OPR_MUL:
		case OPR_DIV:
		case OPR_MOD:
		case OPR_POW:
		{
			if (!isnumeral(v)) luaK_exp2RK(fs, v);
			break;
		}
		default:
		{
			luaK_exp2RK(fs, v);
			break;
		}
	}
}

void luaK_posfix(FuncState *fs, BinOpr op,
				 expdesc *e1, expdesc *e2, int line)
{
	switch (op)
	{
		case OPR_AND:
		{
			lua_assert(e1->t == NO_JUMP); /* list must be closed */
			luaK_dischargevars(fs, e2);
			luaK_concat(fs, &e2->f, e1->f);
			*e1 = *e2;
			break;
		}
		case OPR_OR:
		{
			lua_assert(e1->f == NO_JUMP); /* list must be closed */
			luaK_dischargevars(fs, e2);
			luaK_concat(fs, &e2->t, e1->t);
			*e1 = *e2;
			break;
		}
		case OPR_CONCAT:
		{
			luaK_exp2val(fs, e2);
			if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT)
			{
				lua_assert(e1->u.info == GETARG_B(getcode(fs, e2)) - 1);
				freeexp(fs, e1);
				SETARG_B(getcode(fs, e2), e1->u.info);
				e1->k = VRELOCABLE;
				e1->u.info = e2->u.info;
			}
			else
			{
				luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */
				codearith(fs, OP_CONCAT, e1, e2, line);
			}
			break;
		}
		case OPR_ADD:
		case OPR_SUB:
		case OPR_MUL:
		case OPR_DIV:
		case OPR_MOD:
		case OPR_POW:
		{
			codearith(fs, cast(OpCode, op - OPR_ADD + OP_ADD), e1, e2, line);
			break;
		}
		case OPR_EQ:
		case OPR_LT:
		case OPR_LE:
		{
			codecomp(fs, cast(OpCode, op - OPR_EQ + OP_EQ), 1, e1, e2);
			break;
		}
		case OPR_NE:
		case OPR_GT:
		case OPR_GE:
		{
			codecomp(fs, cast(OpCode, op - OPR_NE + OP_EQ), 0, e1, e2);
			break;
		}
		default:
			lua_assert(0);
	}
}

void luaK_fixline(FuncState *fs, int line)
{
	fs->f->lineinfo[fs->pc - 1] = line;
}

void luaK_setlist(FuncState *fs, int base, int nelems, int tostore)
{
	int c = (nelems - 1) / LFIELDS_PER_FLUSH + 1;
	int b = (tostore == LUA_MULTRET) ? 0 : tostore;
	lua_assert(tostore != 0);
	if (c <= MAXARG_C)
		luaK_codeABC(fs, OP_SETLIST, base, b, c);
	else if (c <= MAXARG_Ax)
	{
		luaK_codeABC(fs, OP_SETLIST, base, b, 0);
		codeextraarg(fs, c);
	}
	else
		luaX_syntaxerror(fs->ls, "constructor too long");
	fs->freereg = base + 1; /* free registers with list values */
}
