/home/mrjunejune/zenbu: third_party/luajit/src/lj

comparison third_party/luajit/src/lj_parse.c @ 186:8cf4ec5e2191 hg-web

Fixed merge conflict.

author	MrJuneJune <me@mrjunejune.com>
date	Fri, 23 Jan 2026 22:38:59 -0800
parents	94705b5986b3
children

comparison

equal deleted inserted replaced

-:fed99fc04e12
+:8cf4ec5e2191
+/*
+** Lua parser (source code -> bytecode).
+** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
+**
+** Major portions taken verbatim or adapted from the Lua interpreter.
+** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
+*/
+#define lj_parse_c
+#define LUA_CORE
+#include "lj_obj.h"
+#include "lj_gc.h"
+#include "lj_err.h"
+#include "lj_debug.h"
+#include "lj_buf.h"
+#include "lj_str.h"
+#include "lj_tab.h"
+#include "lj_func.h"
+#include "lj_state.h"
+#include "lj_bc.h"
+#if LJ_HASFFI
+#include "lj_ctype.h"
+#endif
+#include "lj_strfmt.h"
+#include "lj_lex.h"
+#include "lj_parse.h"
+#include "lj_vm.h"
+#include "lj_vmevent.h"
+/* -- Parser structures and definitions ----------------------------------- */
+/* Expression kinds. */
+typedef enum {
+/* Constant expressions must be first and in this order: */
+VKNIL,
+VKFALSE,
+VKTRUE,
+VKSTR,	/* sval = string value */
+VKNUM,	/* nval = number value */
+VKLAST = VKNUM,
+VKCDATA,	/* nval = cdata value, not treated as a constant expression */
+/* Non-constant expressions follow: */
+VLOCAL,	/* info = local register, aux = vstack index */
+VUPVAL,	/* info = upvalue index, aux = vstack index */
+VGLOBAL,	/* sval = string value */
+VINDEXED,	/* info = table register, aux = index reg/byte/string const */
+VJMP,		/* info = instruction PC */
+VRELOCABLE,	/* info = instruction PC */
+VNONRELOC,	/* info = result register */
+VCALL,	/* info = instruction PC, aux = base */
+VVOID
+} ExpKind;
+/* Expression descriptor. */
+typedef struct ExpDesc {
+union {
+struct {
+uint32_t info;	/* Primary info. */
+uint32_t aux;	/* Secondary info. */
+} s;
+TValue nval;	/* Number value. */
+GCstr *sval;	/* String value. */
+} u;
+ExpKind k;
+BCPos t;		/* True condition jump list. */
+BCPos f;		/* False condition jump list. */
+} ExpDesc;
+/* Macros for expressions. */
+#define expr_hasjump(e)		((e)->t != (e)->f)
+#define expr_isk(e)		((e)->k <= VKLAST)
+#define expr_isk_nojump(e)	(expr_isk(e) && !expr_hasjump(e))
+#define expr_isnumk(e)		((e)->k == VKNUM)
+#define expr_isnumk_nojump(e)	(expr_isnumk(e) && !expr_hasjump(e))
+#define expr_isstrk(e)		((e)->k == VKSTR)
+#define expr_numtv(e)		check_exp(expr_isnumk((e)), &(e)->u.nval)
+#define expr_numberV(e)		numberVnum(expr_numtv((e)))
+/* Initialize expression. */
+static LJ_AINLINE void expr_init(ExpDesc *e, ExpKind k, uint32_t info)
+{
+e->k = k;
+e->u.s.info = info;
+e->f = e->t = NO_JMP;
+}
+/* Check number constant for +-0. */
+static int expr_numiszero(ExpDesc *e)
+{
+TValue *o = expr_numtv(e);
+return tvisint(o) ? (intV(o) == 0) : tviszero(o);
+}
+/* Per-function linked list of scope blocks. */
+typedef struct FuncScope {
+struct FuncScope *prev;	/* Link to outer scope. */
+MSize vstart;			/* Start of block-local variables. */
+uint8_t nactvar;		/* Number of active vars outside the scope. */
+uint8_t flags;		/* Scope flags. */
+} FuncScope;
+#define FSCOPE_LOOP		0x01	/* Scope is a (breakable) loop. */
+#define FSCOPE_BREAK		0x02	/* Break used in scope. */
+#define FSCOPE_GOLA		0x04	/* Goto or label used in scope. */
+#define FSCOPE_UPVAL		0x08	/* Upvalue in scope. */
+#define FSCOPE_NOCLOSE		0x10	/* Do not close upvalues. */
+#define NAME_BREAK		((GCstr *)(uintptr_t)1)
+/* Index into variable stack. */
+typedef uint16_t VarIndex;
+#define LJ_MAX_VSTACK		(65536 - LJ_MAX_UPVAL)
+/* Variable/goto/label info. */
+#define VSTACK_VAR_RW		0x01	/* R/W variable. */
+#define VSTACK_GOTO		0x02	/* Pending goto. */
+#define VSTACK_LABEL		0x04	/* Label. */
+/* Per-function state. */
+typedef struct FuncState {
+GCtab *kt;			/* Hash table for constants. */
+LexState *ls;			/* Lexer state. */
+lua_State *L;			/* Lua state. */
+FuncScope *bl;		/* Current scope. */
+struct FuncState *prev;	/* Enclosing function. */
+BCPos pc;			/* Next bytecode position. */
+BCPos lasttarget;		/* Bytecode position of last jump target. */
+BCPos jpc;			/* Pending jump list to next bytecode. */
+BCReg freereg;		/* First free register. */
+BCReg nactvar;		/* Number of active local variables. */
+BCReg nkn, nkgc;		/* Number of lua_Number/GCobj constants */
+BCLine linedefined;		/* First line of the function definition. */
+BCInsLine *bcbase;		/* Base of bytecode stack. */
+BCPos bclim;			/* Limit of bytecode stack. */
+MSize vbase;			/* Base of variable stack for this function. */
+uint8_t flags;		/* Prototype flags. */
+uint8_t numparams;		/* Number of parameters. */
+uint8_t framesize;		/* Fixed frame size. */
+uint8_t nuv;			/* Number of upvalues */
+VarIndex varmap[LJ_MAX_LOCVAR];  /* Map from register to variable idx. */
+VarIndex uvmap[LJ_MAX_UPVAL];	/* Map from upvalue to variable idx. */
+VarIndex uvtmp[LJ_MAX_UPVAL];	/* Temporary upvalue map. */
+} FuncState;
+/* Binary and unary operators. ORDER OPR */
+typedef enum BinOpr {
+OPR_ADD, OPR_SUB, OPR_MUL, OPR_DIV, OPR_MOD, OPR_POW,  /* ORDER ARITH */
+OPR_CONCAT,
+OPR_NE, OPR_EQ,
+OPR_LT, OPR_GE, OPR_LE, OPR_GT,
+OPR_AND, OPR_OR,
+OPR_NOBINOPR
+} BinOpr;
+LJ_STATIC_ASSERT((int)BC_ISGE-(int)BC_ISLT == (int)OPR_GE-(int)OPR_LT);
+LJ_STATIC_ASSERT((int)BC_ISLE-(int)BC_ISLT == (int)OPR_LE-(int)OPR_LT);
+LJ_STATIC_ASSERT((int)BC_ISGT-(int)BC_ISLT == (int)OPR_GT-(int)OPR_LT);
+LJ_STATIC_ASSERT((int)BC_SUBVV-(int)BC_ADDVV == (int)OPR_SUB-(int)OPR_ADD);
+LJ_STATIC_ASSERT((int)BC_MULVV-(int)BC_ADDVV == (int)OPR_MUL-(int)OPR_ADD);
+LJ_STATIC_ASSERT((int)BC_DIVVV-(int)BC_ADDVV == (int)OPR_DIV-(int)OPR_ADD);
+LJ_STATIC_ASSERT((int)BC_MODVV-(int)BC_ADDVV == (int)OPR_MOD-(int)OPR_ADD);
+#ifdef LUA_USE_ASSERT
+#define lj_assertFS(c, ...)	(lj_assertG_(G(fs->L), (c), __VA_ARGS__))
+#else
+#define lj_assertFS(c, ...)	((void)fs)
+#endif
+/* -- Error handling ------------------------------------------------------ */
+LJ_NORET LJ_NOINLINE static void err_syntax(LexState *ls, ErrMsg em)
+{
+lj_lex_error(ls, ls->tok, em);
+}
+LJ_NORET LJ_NOINLINE static void err_token(LexState *ls, LexToken tok)
+{
+lj_lex_error(ls, ls->tok, LJ_ERR_XTOKEN, lj_lex_token2str(ls, tok));
+}
+LJ_NORET static void err_limit(FuncState *fs, uint32_t limit, const char *what)
+{
+if (fs->linedefined == 0)
+lj_lex_error(fs->ls, 0, LJ_ERR_XLIMM, limit, what);
+else
+lj_lex_error(fs->ls, 0, LJ_ERR_XLIMF, fs->linedefined, limit, what);
+}
+#define checklimit(fs, v, l, m)		if ((v) >= (l)) err_limit(fs, l, m)
+#define checklimitgt(fs, v, l, m)	if ((v) > (l)) err_limit(fs, l, m)
+#define checkcond(ls, c, em)		{ if (!(c)) err_syntax(ls, em); }
+/* -- Management of constants --------------------------------------------- */
+/* Return bytecode encoding for primitive constant. */
+#define const_pri(e)		check_exp((e)->k <= VKTRUE, (e)->k)
+#define tvhaskslot(o)	((o)->u32.hi == 0)
+#define tvkslot(o)	((o)->u32.lo)
+/* Add a number constant. */
+static BCReg const_num(FuncState *fs, ExpDesc *e)
+{
+lua_State *L = fs->L;
+TValue *o;
+lj_assertFS(expr_isnumk(e), "bad usage");
+o = lj_tab_set(L, fs->kt, &e->u.nval);
+if (tvhaskslot(o))
+return tvkslot(o);
+o->u64 = fs->nkn;
+return fs->nkn++;
+}
+/* Add a GC object constant. */
+static BCReg const_gc(FuncState *fs, GCobj *gc, uint32_t itype)
+{
+lua_State *L = fs->L;
+TValue key, *o;
+setgcV(L, &key, gc, itype);
+/* NOBARRIER: the key is new or kept alive. */
+o = lj_tab_set(L, fs->kt, &key);
+if (tvhaskslot(o))
+return tvkslot(o);
+o->u64 = fs->nkgc;
+return fs->nkgc++;
+}
+/* Add a string constant. */
+static BCReg const_str(FuncState *fs, ExpDesc *e)
+{
+lj_assertFS(expr_isstrk(e) || e->k == VGLOBAL, "bad usage");
+return const_gc(fs, obj2gco(e->u.sval), LJ_TSTR);
+}
+/* Anchor string constant to avoid GC. */
+GCstr *lj_parse_keepstr(LexState *ls, const char *str, size_t len)
+{
+/* NOBARRIER: the key is new or kept alive. */
+lua_State *L = ls->L;
+GCstr *s = lj_str_new(L, str, len);
+TValue *tv = lj_tab_setstr(L, ls->fs->kt, s);
+if (tvisnil(tv)) setboolV(tv, 1);
+lj_gc_check(L);
+return s;
+}
+#if LJ_HASFFI
+/* Anchor cdata to avoid GC. */
+void lj_parse_keepcdata(LexState *ls, TValue *tv, GCcdata *cd)
+{
+/* NOBARRIER: the key is new or kept alive. */
+lua_State *L = ls->L;
+setcdataV(L, tv, cd);
+setboolV(lj_tab_set(L, ls->fs->kt, tv), 1);
+}
+#endif
+/* -- Jump list handling -------------------------------------------------- */
+/* Get next element in jump list. */
+static BCPos jmp_next(FuncState *fs, BCPos pc)
+{
+ptrdiff_t delta = bc_j(fs->bcbase[pc].ins);
+if ((BCPos)delta == NO_JMP)
+return NO_JMP;
+else
+return (BCPos)(((ptrdiff_t)pc+1)+delta);
+}
+/* Check if any of the instructions on the jump list produce no value. */
+static int jmp_novalue(FuncState *fs, BCPos list)
+{
+for (; list != NO_JMP; list = jmp_next(fs, list)) {
+BCIns p = fs->bcbase[list >= 1 ? list-1 : list].ins;
+if (!(bc_op(p) == BC_ISTC || bc_op(p) == BC_ISFC || bc_a(p) == NO_REG))
+return 1;
+}
+return 0;
+}
+/* Patch register of test instructions. */
+static int jmp_patchtestreg(FuncState *fs, BCPos pc, BCReg reg)
+{
+BCInsLine *ilp = &fs->bcbase[pc >= 1 ? pc-1 : pc];
+BCOp op = bc_op(ilp->ins);
+if (op == BC_ISTC || op == BC_ISFC) {
+if (reg != NO_REG && reg != bc_d(ilp->ins)) {
+setbc_a(&ilp->ins, reg);
+} else {  /* Nothing to store or already in the right register. */
+setbc_op(&ilp->ins, op+(BC_IST-BC_ISTC));
+setbc_a(&ilp->ins, 0);
+}
+} else if (bc_a(ilp->ins) == NO_REG) {
+if (reg == NO_REG) {
+ilp->ins = BCINS_AJ(BC_JMP, bc_a(fs->bcbase[pc].ins), 0);
+} else {
+setbc_a(&ilp->ins, reg);
+if (reg >= bc_a(ilp[1].ins))
+	setbc_a(&ilp[1].ins, reg+1);
+}
+} else {
+return 0;  /* Cannot patch other instructions. */
+}
+return 1;
+}
+/* Drop values for all instructions on jump list. */
+static void jmp_dropval(FuncState *fs, BCPos list)
+{
+for (; list != NO_JMP; list = jmp_next(fs, list))
+jmp_patchtestreg(fs, list, NO_REG);
+}
+/* Patch jump instruction to target. */
+static void jmp_patchins(FuncState *fs, BCPos pc, BCPos dest)
+{
+BCIns *jmp = &fs->bcbase[pc].ins;
+BCPos offset = dest-(pc+1)+BCBIAS_J;
+lj_assertFS(dest != NO_JMP, "uninitialized jump target");
+if (offset > BCMAX_D)
+err_syntax(fs->ls, LJ_ERR_XJUMP);
+setbc_d(jmp, offset);
+}
+/* Append to jump list. */
+static void jmp_append(FuncState *fs, BCPos *l1, BCPos l2)
+{
+if (l2 == NO_JMP) {
+return;
+} else if (*l1 == NO_JMP) {
+*l1 = l2;
+} else {
+BCPos list = *l1;
+BCPos next;
+while ((next = jmp_next(fs, list)) != NO_JMP)  /* Find last element. */
+list = next;
+jmp_patchins(fs, list, l2);
+}
+}
+/* Patch jump list and preserve produced values. */
+static void jmp_patchval(FuncState *fs, BCPos list, BCPos vtarget,
+			 BCReg reg, BCPos dtarget)
+{
+while (list != NO_JMP) {
+BCPos next = jmp_next(fs, list);
+if (jmp_patchtestreg(fs, list, reg))
+jmp_patchins(fs, list, vtarget);  /* Jump to target with value. */
+else
+jmp_patchins(fs, list, dtarget);  /* Jump to default target. */
+list = next;
+}
+}
+/* Jump to following instruction. Append to list of pending jumps. */
+static void jmp_tohere(FuncState *fs, BCPos list)
+{
+fs->lasttarget = fs->pc;
+jmp_append(fs, &fs->jpc, list);
+}
+/* Patch jump list to target. */
+static void jmp_patch(FuncState *fs, BCPos list, BCPos target)
+{
+if (target == fs->pc) {
+jmp_tohere(fs, list);
+} else {
+lj_assertFS(target < fs->pc, "bad jump target");
+jmp_patchval(fs, list, target, NO_REG, target);
+}
+}
+/* -- Bytecode register allocator ----------------------------------------- */
+/* Bump frame size. */
+static void bcreg_bump(FuncState *fs, BCReg n)
+{
+BCReg sz = fs->freereg + n;
+if (sz > fs->framesize) {
+if (sz >= LJ_MAX_SLOTS)
+err_syntax(fs->ls, LJ_ERR_XSLOTS);
+fs->framesize = (uint8_t)sz;
+}
+}
+/* Reserve registers. */
+static void bcreg_reserve(FuncState *fs, BCReg n)
+{
+bcreg_bump(fs, n);
+fs->freereg += n;
+}
+/* Free register. */
+static void bcreg_free(FuncState *fs, BCReg reg)
+{
+if (reg >= fs->nactvar) {
+fs->freereg--;
+lj_assertFS(reg == fs->freereg, "bad regfree");
+}
+}
+/* Free register for expression. */
+static void expr_free(FuncState *fs, ExpDesc *e)
+{
+if (e->k == VNONRELOC)
+bcreg_free(fs, e->u.s.info);
+}
+/* -- Bytecode emitter ---------------------------------------------------- */
+/* Emit bytecode instruction. */
+static BCPos bcemit_INS(FuncState *fs, BCIns ins)
+{
+BCPos pc = fs->pc;
+LexState *ls = fs->ls;
+jmp_patchval(fs, fs->jpc, pc, NO_REG, pc);
+fs->jpc = NO_JMP;
+if (LJ_UNLIKELY(pc >= fs->bclim)) {
+ptrdiff_t base = fs->bcbase - ls->bcstack;
+checklimit(fs, ls->sizebcstack, LJ_MAX_BCINS, "bytecode instructions");
+lj_mem_growvec(fs->L, ls->bcstack, ls->sizebcstack, LJ_MAX_BCINS,BCInsLine);
+fs->bclim = (BCPos)(ls->sizebcstack - base);
+fs->bcbase = ls->bcstack + base;
+}
+fs->bcbase[pc].ins = ins;
+fs->bcbase[pc].line = ls->lastline;
+fs->pc = pc+1;
+return pc;
+}
+#define bcemit_ABC(fs, o, a, b, c)	bcemit_INS(fs, BCINS_ABC(o, a, b, c))
+#define bcemit_AD(fs, o, a, d)		bcemit_INS(fs, BCINS_AD(o, a, d))
+#define bcemit_AJ(fs, o, a, j)		bcemit_INS(fs, BCINS_AJ(o, a, j))
+#define bcptr(fs, e)			(&(fs)->bcbase[(e)->u.s.info].ins)
+/* -- Bytecode emitter for expressions ------------------------------------ */
+/* Discharge non-constant expression to any register. */
+static void expr_discharge(FuncState *fs, ExpDesc *e)
+{
+BCIns ins;
+if (e->k == VUPVAL) {
+ins = BCINS_AD(BC_UGET, 0, e->u.s.info);
+} else if (e->k == VGLOBAL) {
+ins = BCINS_AD(BC_GGET, 0, const_str(fs, e));
+} else if (e->k == VINDEXED) {
+BCReg rc = e->u.s.aux;
+if ((int32_t)rc < 0) {
+ins = BCINS_ABC(BC_TGETS, 0, e->u.s.info, ~rc);
+} else if (rc > BCMAX_C) {
+ins = BCINS_ABC(BC_TGETB, 0, e->u.s.info, rc-(BCMAX_C+1));
+} else {
+bcreg_free(fs, rc);
+ins = BCINS_ABC(BC_TGETV, 0, e->u.s.info, rc);
+}
+bcreg_free(fs, e->u.s.info);
+} else if (e->k == VCALL) {
+e->u.s.info = e->u.s.aux;
+e->k = VNONRELOC;
+return;
+} else if (e->k == VLOCAL) {
+e->k = VNONRELOC;
+return;
+} else {
+return;
+}
+e->u.s.info = bcemit_INS(fs, ins);
+e->k = VRELOCABLE;
+}
+/* Emit bytecode to set a range of registers to nil. */
+static void bcemit_nil(FuncState *fs, BCReg from, BCReg n)
+{
+if (fs->pc > fs->lasttarget) {  /* No jumps to current position? */
+BCIns *ip = &fs->bcbase[fs->pc-1].ins;
+BCReg pto, pfrom = bc_a(*ip);
+switch (bc_op(*ip)) {  /* Try to merge with the previous instruction. */
+case BC_KPRI:
+if (bc_d(*ip) != ~LJ_TNIL) break;
+if (from == pfrom) {
+	if (n == 1) return;
+} else if (from == pfrom+1) {
+	from = pfrom;
+	n++;
+} else {
+	break;
+}
+*ip = BCINS_AD(BC_KNIL, from, from+n-1);  /* Replace KPRI. */
+return;
+case BC_KNIL:
+pto = bc_d(*ip);
+if (pfrom <= from && from <= pto+1) {  /* Can we connect both ranges? */
+	if (from+n-1 > pto)
+	  setbc_d(ip, from+n-1);  /* Patch previous instruction range. */
+	return;
+}
+break;
+default:
+break;
+}
+}
+/* Emit new instruction or replace old instruction. */
+bcemit_INS(fs, n == 1 ? BCINS_AD(BC_KPRI, from, VKNIL) :
+			  BCINS_AD(BC_KNIL, from, from+n-1));
+}
+/* Discharge an expression to a specific register. Ignore branches. */
+static void expr_toreg_nobranch(FuncState *fs, ExpDesc *e, BCReg reg)
+{
+BCIns ins;
+expr_discharge(fs, e);
+if (e->k == VKSTR) {
+ins = BCINS_AD(BC_KSTR, reg, const_str(fs, e));
+} else if (e->k == VKNUM) {
+#if LJ_DUALNUM
+cTValue *tv = expr_numtv(e);
+if (tvisint(tv) && checki16(intV(tv)))
+ins = BCINS_AD(BC_KSHORT, reg, (BCReg)(uint16_t)intV(tv));
+else
+#else
+lua_Number n = expr_numberV(e);
+int32_t k = lj_num2int(n);
+if (checki16(k) && n == (lua_Number)k)
+ins = BCINS_AD(BC_KSHORT, reg, (BCReg)(uint16_t)k);
+else
+#endif
+ins = BCINS_AD(BC_KNUM, reg, const_num(fs, e));
+#if LJ_HASFFI
+} else if (e->k == VKCDATA) {
+fs->flags |= PROTO_FFI;
+ins = BCINS_AD(BC_KCDATA, reg,
+		   const_gc(fs, obj2gco(cdataV(&e->u.nval)), LJ_TCDATA));
+#endif
+} else if (e->k == VRELOCABLE) {
+setbc_a(bcptr(fs, e), reg);
+goto noins;
+} else if (e->k == VNONRELOC) {
+if (reg == e->u.s.info)
+goto noins;
+ins = BCINS_AD(BC_MOV, reg, e->u.s.info);
+} else if (e->k == VKNIL) {
+bcemit_nil(fs, reg, 1);
+goto noins;
+} else if (e->k <= VKTRUE) {
+ins = BCINS_AD(BC_KPRI, reg, const_pri(e));
+} else {
+lj_assertFS(e->k == VVOID || e->k == VJMP, "bad expr type %d", e->k);
+return;
+}
+bcemit_INS(fs, ins);
+noins:
+e->u.s.info = reg;
+e->k = VNONRELOC;
+}
+/* Forward declaration. */
+static BCPos bcemit_jmp(FuncState *fs);
+/* Discharge an expression to a specific register. */
+static void expr_toreg(FuncState *fs, ExpDesc *e, BCReg reg)
+{
+expr_toreg_nobranch(fs, e, reg);
+if (e->k == VJMP)
+jmp_append(fs, &e->t, e->u.s.info);  /* Add it to the true jump list. */
+if (expr_hasjump(e)) {  /* Discharge expression with branches. */
+BCPos jend, jfalse = NO_JMP, jtrue = NO_JMP;
+if (jmp_novalue(fs, e->t) || jmp_novalue(fs, e->f)) {
+BCPos jval = (e->k == VJMP) ? NO_JMP : bcemit_jmp(fs);
+jfalse = bcemit_AD(fs, BC_KPRI, reg, VKFALSE);
+bcemit_AJ(fs, BC_JMP, fs->freereg, 1);
+jtrue = bcemit_AD(fs, BC_KPRI, reg, VKTRUE);
+jmp_tohere(fs, jval);
+}
+jend = fs->pc;
+fs->lasttarget = jend;
+jmp_patchval(fs, e->f, jend, reg, jfalse);
+jmp_patchval(fs, e->t, jend, reg, jtrue);
+}
+e->f = e->t = NO_JMP;
+e->u.s.info = reg;
+e->k = VNONRELOC;
+}
+/* Discharge an expression to the next free register. */
+static void expr_tonextreg(FuncState *fs, ExpDesc *e)
+{
+expr_discharge(fs, e);
+expr_free(fs, e);
+bcreg_reserve(fs, 1);
+expr_toreg(fs, e, fs->freereg - 1);
+}
+/* Discharge an expression to any register. */
+static BCReg expr_toanyreg(FuncState *fs, ExpDesc *e)
+{
+expr_discharge(fs, e);
+if (e->k == VNONRELOC) {
+if (!expr_hasjump(e)) return e->u.s.info;  /* Already in a register. */
+if (e->u.s.info >= fs->nactvar) {
+expr_toreg(fs, e, e->u.s.info);  /* Discharge to temp. register. */
+return e->u.s.info;
+}
+}
+expr_tonextreg(fs, e);  /* Discharge to next register. */
+return e->u.s.info;
+}
+/* Partially discharge expression to a value. */
+static void expr_toval(FuncState *fs, ExpDesc *e)
+{
+if (expr_hasjump(e))
+expr_toanyreg(fs, e);
+else
+expr_discharge(fs, e);
+}
+/* Emit store for LHS expression. */
+static void bcemit_store(FuncState *fs, ExpDesc *var, ExpDesc *e)
+{
+BCIns ins;
+if (var->k == VLOCAL) {
+fs->ls->vstack[var->u.s.aux].info |= VSTACK_VAR_RW;
+expr_free(fs, e);
+expr_toreg(fs, e, var->u.s.info);
+return;
+} else if (var->k == VUPVAL) {
+fs->ls->vstack[var->u.s.aux].info |= VSTACK_VAR_RW;
+expr_toval(fs, e);
+if (e->k <= VKTRUE)
+ins = BCINS_AD(BC_USETP, var->u.s.info, const_pri(e));
+else if (e->k == VKSTR)
+ins = BCINS_AD(BC_USETS, var->u.s.info, const_str(fs, e));
+else if (e->k == VKNUM)
+ins = BCINS_AD(BC_USETN, var->u.s.info, const_num(fs, e));
+else
+ins = BCINS_AD(BC_USETV, var->u.s.info, expr_toanyreg(fs, e));
+} else if (var->k == VGLOBAL) {
+BCReg ra = expr_toanyreg(fs, e);
+ins = BCINS_AD(BC_GSET, ra, const_str(fs, var));
+} else {
+BCReg ra, rc;
+lj_assertFS(var->k == VINDEXED, "bad expr type %d", var->k);
+ra = expr_toanyreg(fs, e);
+rc = var->u.s.aux;
+if ((int32_t)rc < 0) {
+ins = BCINS_ABC(BC_TSETS, ra, var->u.s.info, ~rc);
+} else if (rc > BCMAX_C) {
+ins = BCINS_ABC(BC_TSETB, ra, var->u.s.info, rc-(BCMAX_C+1));
+} else {
+#ifdef LUA_USE_ASSERT
+/* Free late alloced key reg to avoid assert on free of value reg. */
+/* This can only happen when called from expr_table(). */
+if (e->k == VNONRELOC && ra >= fs->nactvar && rc >= ra)
+	bcreg_free(fs, rc);
+#endif
+ins = BCINS_ABC(BC_TSETV, ra, var->u.s.info, rc);
+}
+}
+bcemit_INS(fs, ins);
+expr_free(fs, e);
+}
+/* Emit method lookup expression. */
+static void bcemit_method(FuncState *fs, ExpDesc *e, ExpDesc *key)
+{
+BCReg idx, func, obj = expr_toanyreg(fs, e);
+expr_free(fs, e);
+func = fs->freereg;
+bcemit_AD(fs, BC_MOV, func+1+LJ_FR2, obj);  /* Copy object to 1st argument. */
+lj_assertFS(expr_isstrk(key), "bad usage");
+idx = const_str(fs, key);
+if (idx <= BCMAX_C) {
+bcreg_reserve(fs, 2+LJ_FR2);
+bcemit_ABC(fs, BC_TGETS, func, obj, idx);
+} else {
+bcreg_reserve(fs, 3+LJ_FR2);
+bcemit_AD(fs, BC_KSTR, func+2+LJ_FR2, idx);
+bcemit_ABC(fs, BC_TGETV, func, obj, func+2+LJ_FR2);
+fs->freereg--;
+}
+e->u.s.info = func;
+e->k = VNONRELOC;
+}
+/* -- Bytecode emitter for branches --------------------------------------- */
+/* Emit unconditional branch. */
+static BCPos bcemit_jmp(FuncState *fs)
+{
+BCPos jpc = fs->jpc;
+BCPos j = fs->pc - 1;
+BCIns *ip = &fs->bcbase[j].ins;
+fs->jpc = NO_JMP;
+if ((int32_t)j >= (int32_t)fs->lasttarget && bc_op(*ip) == BC_UCLO) {
+setbc_j(ip, NO_JMP);
+fs->lasttarget = j+1;
+} else {
+j = bcemit_AJ(fs, BC_JMP, fs->freereg, NO_JMP);
+}
+jmp_append(fs, &j, jpc);
+return j;
+}
+/* Invert branch condition of bytecode instruction. */
+static void invertcond(FuncState *fs, ExpDesc *e)
+{
+BCIns *ip = &fs->bcbase[e->u.s.info - 1].ins;
+setbc_op(ip, bc_op(*ip)^1);
+}
+/* Emit conditional branch. */
+static BCPos bcemit_branch(FuncState *fs, ExpDesc *e, int cond)
+{
+BCPos pc;
+if (e->k == VRELOCABLE) {
+BCIns *ip = bcptr(fs, e);
+if (bc_op(*ip) == BC_NOT) {
+*ip = BCINS_AD(cond ? BC_ISF : BC_IST, 0, bc_d(*ip));
+return bcemit_jmp(fs);
+}
+}
+if (e->k != VNONRELOC) {
+bcreg_reserve(fs, 1);
+expr_toreg_nobranch(fs, e, fs->freereg-1);
+}
+bcemit_AD(fs, cond ? BC_ISTC : BC_ISFC, NO_REG, e->u.s.info);
+pc = bcemit_jmp(fs);
+expr_free(fs, e);
+return pc;
+}
+/* Emit branch on true condition. */
+static void bcemit_branch_t(FuncState *fs, ExpDesc *e)
+{
+BCPos pc;
+expr_discharge(fs, e);
+if (e->k == VKSTR || e->k == VKNUM || e->k == VKTRUE)
+pc = NO_JMP;  /* Never jump. */
+else if (e->k == VJMP)
+invertcond(fs, e), pc = e->u.s.info;
+else if (e->k == VKFALSE || e->k == VKNIL)
+expr_toreg_nobranch(fs, e, NO_REG), pc = bcemit_jmp(fs);
+else
+pc = bcemit_branch(fs, e, 0);
+jmp_append(fs, &e->f, pc);
+jmp_tohere(fs, e->t);
+e->t = NO_JMP;
+}
+/* Emit branch on false condition. */
+static void bcemit_branch_f(FuncState *fs, ExpDesc *e)
+{
+BCPos pc;
+expr_discharge(fs, e);
+if (e->k == VKNIL || e->k == VKFALSE)
+pc = NO_JMP;  /* Never jump. */
+else if (e->k == VJMP)
+pc = e->u.s.info;
+else if (e->k == VKSTR || e->k == VKNUM || e->k == VKTRUE)
+expr_toreg_nobranch(fs, e, NO_REG), pc = bcemit_jmp(fs);
+else
+pc = bcemit_branch(fs, e, 1);
+jmp_append(fs, &e->t, pc);
+jmp_tohere(fs, e->f);
+e->f = NO_JMP;
+}
+/* -- Bytecode emitter for operators -------------------------------------- */
+/* Try constant-folding of arithmetic operators. */
+static int foldarith(BinOpr opr, ExpDesc *e1, ExpDesc *e2)
+{
+TValue o;
+lua_Number n;
+if (!expr_isnumk_nojump(e1) || !expr_isnumk_nojump(e2)) return 0;
+n = lj_vm_foldarith(expr_numberV(e1), expr_numberV(e2), (int)opr-OPR_ADD);
+setnumV(&o, n);
+if (tvisnan(&o) || tvismzero(&o)) return 0;  /* Avoid NaN and -0 as consts. */
+if (LJ_DUALNUM) {
+int32_t k = lj_num2int(n);
+if ((lua_Number)k == n) {
+setintV(&e1->u.nval, k);
+return 1;
+}
+}
+setnumV(&e1->u.nval, n);
+return 1;
+}
+/* Emit arithmetic operator. */
+static void bcemit_arith(FuncState *fs, BinOpr opr, ExpDesc *e1, ExpDesc *e2)
+{
+BCReg rb, rc, t;
+uint32_t op;
+if (foldarith(opr, e1, e2))
+return;
+if (opr == OPR_POW) {
+op = BC_POW;
+rc = expr_toanyreg(fs, e2);
+rb = expr_toanyreg(fs, e1);
+} else {
+op = opr-OPR_ADD+BC_ADDVV;
+/* Must discharge 2nd operand first since VINDEXED might free regs. */
+expr_toval(fs, e2);
+if (expr_isnumk(e2) && (rc = const_num(fs, e2)) <= BCMAX_C)
+op -= BC_ADDVV-BC_ADDVN;
+else
+rc = expr_toanyreg(fs, e2);
+/* 1st operand discharged by bcemit_binop_left, but need KNUM/KSHORT. */
+lj_assertFS(expr_isnumk(e1) || e1->k == VNONRELOC,
+		"bad expr type %d", e1->k);
+expr_toval(fs, e1);
+/* Avoid two consts to satisfy bytecode constraints. */
+if (expr_isnumk(e1) && !expr_isnumk(e2) &&
+	(t = const_num(fs, e1)) <= BCMAX_B) {
+rb = rc; rc = t; op -= BC_ADDVV-BC_ADDNV;
+} else {
+rb = expr_toanyreg(fs, e1);
+}
+}
+/* Using expr_free might cause asserts if the order is wrong. */
+if (e1->k == VNONRELOC && e1->u.s.info >= fs->nactvar) fs->freereg--;
+if (e2->k == VNONRELOC && e2->u.s.info >= fs->nactvar) fs->freereg--;
+e1->u.s.info = bcemit_ABC(fs, op, 0, rb, rc);
+e1->k = VRELOCABLE;
+}
+/* Emit comparison operator. */
+static void bcemit_comp(FuncState *fs, BinOpr opr, ExpDesc *e1, ExpDesc *e2)
+{
+ExpDesc *eret = e1;
+BCIns ins;
+expr_toval(fs, e1);
+if (opr == OPR_EQ || opr == OPR_NE) {
+BCOp op = opr == OPR_EQ ? BC_ISEQV : BC_ISNEV;
+BCReg ra;
+if (expr_isk(e1)) { e1 = e2; e2 = eret; }  /* Need constant in 2nd arg. */
+ra = expr_toanyreg(fs, e1);  /* First arg must be in a reg. */
+expr_toval(fs, e2);
+switch (e2->k) {
+case VKNIL: case VKFALSE: case VKTRUE:
+ins = BCINS_AD(op+(BC_ISEQP-BC_ISEQV), ra, const_pri(e2));
+break;
+case VKSTR:
+ins = BCINS_AD(op+(BC_ISEQS-BC_ISEQV), ra, const_str(fs, e2));
+break;
+case VKNUM:
+ins = BCINS_AD(op+(BC_ISEQN-BC_ISEQV), ra, const_num(fs, e2));
+break;
+default:
+ins = BCINS_AD(op, ra, expr_toanyreg(fs, e2));
+break;
+}
+} else {
+uint32_t op = opr-OPR_LT+BC_ISLT;
+BCReg ra, rd;
+if ((op-BC_ISLT) & 1) {  /* GT -> LT, GE -> LE */
+e1 = e2; e2 = eret;  /* Swap operands. */
+op = ((op-BC_ISLT)^3)+BC_ISLT;
+expr_toval(fs, e1);
+ra = expr_toanyreg(fs, e1);
+rd = expr_toanyreg(fs, e2);
+} else {
+rd = expr_toanyreg(fs, e2);
+ra = expr_toanyreg(fs, e1);
+}
+ins = BCINS_AD(op, ra, rd);
+}
+/* Using expr_free might cause asserts if the order is wrong. */
+if (e1->k == VNONRELOC && e1->u.s.info >= fs->nactvar) fs->freereg--;
+if (e2->k == VNONRELOC && e2->u.s.info >= fs->nactvar) fs->freereg--;
+bcemit_INS(fs, ins);
+eret->u.s.info = bcemit_jmp(fs);
+eret->k = VJMP;
+}
+/* Fixup left side of binary operator. */
+static void bcemit_binop_left(FuncState *fs, BinOpr op, ExpDesc *e)
+{
+if (op == OPR_AND) {
+bcemit_branch_t(fs, e);
+} else if (op == OPR_OR) {
+bcemit_branch_f(fs, e);
+} else if (op == OPR_CONCAT) {
+expr_tonextreg(fs, e);
+} else if (op == OPR_EQ || op == OPR_NE) {
+if (!expr_isk_nojump(e)) expr_toanyreg(fs, e);
+} else {
+if (!expr_isnumk_nojump(e)) expr_toanyreg(fs, e);
+}
+}
+/* Emit binary operator. */
+static void bcemit_binop(FuncState *fs, BinOpr op, ExpDesc *e1, ExpDesc *e2)
+{
+if (op <= OPR_POW) {
+bcemit_arith(fs, op, e1, e2);
+} else if (op == OPR_AND) {
+lj_assertFS(e1->t == NO_JMP, "jump list not closed");
+expr_discharge(fs, e2);
+jmp_append(fs, &e2->f, e1->f);
+*e1 = *e2;
+} else if (op == OPR_OR) {
+lj_assertFS(e1->f == NO_JMP, "jump list not closed");
+expr_discharge(fs, e2);
+jmp_append(fs, &e2->t, e1->t);
+*e1 = *e2;
+} else if (op == OPR_CONCAT) {
+expr_toval(fs, e2);
+if (e2->k == VRELOCABLE && bc_op(*bcptr(fs, e2)) == BC_CAT) {
+lj_assertFS(e1->u.s.info == bc_b(*bcptr(fs, e2))-1,
+		  "bad CAT stack layout");
+expr_free(fs, e1);
+setbc_b(bcptr(fs, e2), e1->u.s.info);
+e1->u.s.info = e2->u.s.info;
+} else {
+expr_tonextreg(fs, e2);
+expr_free(fs, e2);
+expr_free(fs, e1);
+e1->u.s.info = bcemit_ABC(fs, BC_CAT, 0, e1->u.s.info, e2->u.s.info);
+}
+e1->k = VRELOCABLE;
+} else {
+lj_assertFS(op == OPR_NE || op == OPR_EQ ||
+	       op == OPR_LT || op == OPR_GE || op == OPR_LE || op == OPR_GT,
+	       "bad binop %d", op);
+bcemit_comp(fs, op, e1, e2);
+}
+}
+/* Emit unary operator. */
+static void bcemit_unop(FuncState *fs, BCOp op, ExpDesc *e)
+{
+if (op == BC_NOT) {
+/* Swap true and false lists. */
+{ BCPos temp = e->f; e->f = e->t; e->t = temp; }
+jmp_dropval(fs, e->f);
+jmp_dropval(fs, e->t);
+expr_discharge(fs, e);
+if (e->k == VKNIL || e->k == VKFALSE) {
+e->k = VKTRUE;
+return;
+} else if (expr_isk(e) || (LJ_HASFFI && e->k == VKCDATA)) {
+e->k = VKFALSE;
+return;
+} else if (e->k == VJMP) {
+invertcond(fs, e);
+return;
+} else if (e->k == VRELOCABLE) {
+bcreg_reserve(fs, 1);
+setbc_a(bcptr(fs, e), fs->freereg-1);
+e->u.s.info = fs->freereg-1;
+e->k = VNONRELOC;
+} else {
+lj_assertFS(e->k == VNONRELOC, "bad expr type %d", e->k);
+}
+} else {
+lj_assertFS(op == BC_UNM || op == BC_LEN, "bad unop %d", op);
+if (op == BC_UNM && !expr_hasjump(e)) {  /* Constant-fold negations. */
+#if LJ_HASFFI
+if (e->k == VKCDATA) {  /* Fold in-place since cdata is not interned. */
+	GCcdata *cd = cdataV(&e->u.nval);
+	uint64_t *p = (uint64_t *)cdataptr(cd);
+	if (cd->ctypeid == CTID_COMPLEX_DOUBLE)
+	  p[1] ^= U64x(80000000,00000000);
+	else
+	  *p = ~*p+1u;
+	return;
+} else
+#endif
+if (expr_isnumk(e) && !expr_numiszero(e)) {  /* Avoid folding to -0. */
+	TValue *o = expr_numtv(e);
+	if (tvisint(o)) {
+	  int32_t k = intV(o), negk = (int32_t)(~(uint32_t)k+1u);
+	  if (k == negk)
+	    setnumV(o, -(lua_Number)k);
+	  else
+	    setintV(o, negk);
+	  return;
+	} else {
+	  o->u64 ^= U64x(80000000,00000000);
+	  return;
+	}
+}
+}
+expr_toanyreg(fs, e);
+}
+expr_free(fs, e);
+e->u.s.info = bcemit_AD(fs, op, 0, e->u.s.info);
+e->k = VRELOCABLE;
+}
+/* -- Lexer support ------------------------------------------------------- */
+/* Check and consume optional token. */
+static int lex_opt(LexState *ls, LexToken tok)
+{
+if (ls->tok == tok) {
+lj_lex_next(ls);
+return 1;
+}
+return 0;
+}
+/* Check and consume token. */
+static void lex_check(LexState *ls, LexToken tok)
+{
+if (ls->tok != tok)
+err_token(ls, tok);
+lj_lex_next(ls);
+}
+/* Check for matching token. */
+static void lex_match(LexState *ls, LexToken what, LexToken who, BCLine line)
+{
+if (!lex_opt(ls, what)) {
+if (line == ls->linenumber) {
+err_token(ls, what);
+} else {
+const char *swhat = lj_lex_token2str(ls, what);
+const char *swho = lj_lex_token2str(ls, who);
+lj_lex_error(ls, ls->tok, LJ_ERR_XMATCH, swhat, swho, line);
+}
+}
+}
+/* Check for string token. */
+static GCstr *lex_str(LexState *ls)
+{
+GCstr *s;
+if (ls->tok != TK_name && (LJ_52 || ls->tok != TK_goto))
+err_token(ls, TK_name);
+s = strV(&ls->tokval);
+lj_lex_next(ls);
+return s;
+}
+/* -- Variable handling --------------------------------------------------- */
+#define var_get(ls, fs, i)	((ls)->vstack[(fs)->varmap[(i)]])
+/* Define a new local variable. */
+static void var_new(LexState *ls, BCReg n, GCstr *name)
+{
+FuncState *fs = ls->fs;
+MSize vtop = ls->vtop;
+checklimit(fs, fs->nactvar+n, LJ_MAX_LOCVAR, "local variables");
+if (LJ_UNLIKELY(vtop >= ls->sizevstack)) {
+if (ls->sizevstack >= LJ_MAX_VSTACK)
+lj_lex_error(ls, 0, LJ_ERR_XLIMC, LJ_MAX_VSTACK);
+lj_mem_growvec(ls->L, ls->vstack, ls->sizevstack, LJ_MAX_VSTACK, VarInfo);
+}
+lj_assertFS((uintptr_t)name < VARNAME__MAX ||
+	      lj_tab_getstr(fs->kt, name) != NULL,
+	      "unanchored variable name");
+/* NOBARRIER: name is anchored in fs->kt and ls->vstack is not a GCobj. */
+setgcref(ls->vstack[vtop].name, obj2gco(name));
+fs->varmap[fs->nactvar+n] = (uint16_t)vtop;
+ls->vtop = vtop+1;
+}
+#define var_new_lit(ls, n, v) \
+var_new(ls, (n), lj_parse_keepstr(ls, "" v, sizeof(v)-1))
+#define var_new_fixed(ls, n, vn) \
+var_new(ls, (n), (GCstr *)(uintptr_t)(vn))
+/* Add local variables. */
+static void var_add(LexState *ls, BCReg nvars)
+{
+FuncState *fs = ls->fs;
+BCReg nactvar = fs->nactvar;
+while (nvars--) {
+VarInfo *v = &var_get(ls, fs, nactvar);
+v->startpc = fs->pc;
+v->slot = nactvar++;
+v->info = 0;
+}
+fs->nactvar = nactvar;
+}
+/* Remove local variables. */
+static void var_remove(LexState *ls, BCReg tolevel)
+{
+FuncState *fs = ls->fs;
+while (fs->nactvar > tolevel)
+var_get(ls, fs, --fs->nactvar).endpc = fs->pc;
+}
+/* Lookup local variable name. */
+static BCReg var_lookup_local(FuncState *fs, GCstr *n)
+{
+int i;
+for (i = fs->nactvar-1; i >= 0; i--) {
+if (n == strref(var_get(fs->ls, fs, i).name))
+return (BCReg)i;
+}
+return (BCReg)-1;  /* Not found. */
+}
+/* Lookup or add upvalue index. */
+static MSize var_lookup_uv(FuncState *fs, MSize vidx, ExpDesc *e)
+{
+MSize i, n = fs->nuv;
+for (i = 0; i < n; i++)
+if (fs->uvmap[i] == vidx)
+return i;  /* Already exists. */
+/* Otherwise create a new one. */
+checklimit(fs, fs->nuv, LJ_MAX_UPVAL, "upvalues");
+lj_assertFS(e->k == VLOCAL || e->k == VUPVAL, "bad expr type %d", e->k);
+fs->uvmap[n] = (uint16_t)vidx;
+fs->uvtmp[n] = (uint16_t)(e->k == VLOCAL ? vidx : LJ_MAX_VSTACK+e->u.s.info);
+fs->nuv = n+1;
+return n;
+}
+/* Forward declaration. */
+static void fscope_uvmark(FuncState *fs, BCReg level);
+/* Recursively lookup variables in enclosing functions. */
+static MSize var_lookup_(FuncState *fs, GCstr *name, ExpDesc *e, int first)
+{
+if (fs) {
+BCReg reg = var_lookup_local(fs, name);
+if ((int32_t)reg >= 0) {  /* Local in this function? */
+expr_init(e, VLOCAL, reg);
+if (!first)
+	fscope_uvmark(fs, reg);  /* Scope now has an upvalue. */
+return (MSize)(e->u.s.aux = (uint32_t)fs->varmap[reg]);
+} else {
+MSize vidx = var_lookup_(fs->prev, name, e, 0);  /* Var in outer func? */
+if ((int32_t)vidx >= 0) {  /* Yes, make it an upvalue here. */
+	e->u.s.info = (uint8_t)var_lookup_uv(fs, vidx, e);
+	e->k = VUPVAL;
+	return vidx;
+}
+}
+} else {  /* Not found in any function, must be a global. */
+expr_init(e, VGLOBAL, 0);
+e->u.sval = name;
+}
+return (MSize)-1;  /* Global. */
+}
+/* Lookup variable name. */
+#define var_lookup(ls, e) \
+var_lookup_((ls)->fs, lex_str(ls), (e), 1)
+/* -- Goto an label handling ---------------------------------------------- */
+/* Add a new goto or label. */
+static MSize gola_new(LexState *ls, GCstr *name, uint8_t info, BCPos pc)
+{
+FuncState *fs = ls->fs;
+MSize vtop = ls->vtop;
+if (LJ_UNLIKELY(vtop >= ls->sizevstack)) {
+if (ls->sizevstack >= LJ_MAX_VSTACK)
+lj_lex_error(ls, 0, LJ_ERR_XLIMC, LJ_MAX_VSTACK);
+lj_mem_growvec(ls->L, ls->vstack, ls->sizevstack, LJ_MAX_VSTACK, VarInfo);
+}
+lj_assertFS(name == NAME_BREAK || lj_tab_getstr(fs->kt, name) != NULL,
+	      "unanchored label name");
+/* NOBARRIER: name is anchored in fs->kt and ls->vstack is not a GCobj. */
+setgcref(ls->vstack[vtop].name, obj2gco(name));
+ls->vstack[vtop].startpc = pc;
+ls->vstack[vtop].slot = (uint8_t)fs->nactvar;
+ls->vstack[vtop].info = info;
+ls->vtop = vtop+1;
+return vtop;
+}
+#define gola_isgoto(v)		((v)->info & VSTACK_GOTO)
+#define gola_islabel(v)		((v)->info & VSTACK_LABEL)
+#define gola_isgotolabel(v)	((v)->info & (VSTACK_GOTO|VSTACK_LABEL))
+/* Patch goto to jump to label. */
+static void gola_patch(LexState *ls, VarInfo *vg, VarInfo *vl)
+{
+FuncState *fs = ls->fs;
+BCPos pc = vg->startpc;
+setgcrefnull(vg->name);  /* Invalidate pending goto. */
+setbc_a(&fs->bcbase[pc].ins, vl->slot);
+jmp_patch(fs, pc, vl->startpc);
+}
+/* Patch goto to close upvalues. */
+static void gola_close(LexState *ls, VarInfo *vg)
+{
+FuncState *fs = ls->fs;
+BCPos pc = vg->startpc;
+BCIns *ip = &fs->bcbase[pc].ins;
+lj_assertFS(gola_isgoto(vg), "expected goto");
+lj_assertFS(bc_op(*ip) == BC_JMP || bc_op(*ip) == BC_UCLO,
+	      "bad bytecode op %d", bc_op(*ip));
+setbc_a(ip, vg->slot);
+if (bc_op(*ip) == BC_JMP) {
+BCPos next = jmp_next(fs, pc);
+if (next != NO_JMP) jmp_patch(fs, next, pc);  /* Jump to UCLO. */
+setbc_op(ip, BC_UCLO);  /* Turn into UCLO. */
+setbc_j(ip, NO_JMP);
+}
+}
+/* Resolve pending forward gotos for label. */
+static void gola_resolve(LexState *ls, FuncScope *bl, MSize idx)
+{
+VarInfo *vg = ls->vstack + bl->vstart;
+VarInfo *vl = ls->vstack + idx;
+for (; vg < vl; vg++)
+if (gcrefeq(vg->name, vl->name) && gola_isgoto(vg)) {
+if (vg->slot < vl->slot) {
+	GCstr *name = strref(var_get(ls, ls->fs, vg->slot).name);
+	lj_assertLS((uintptr_t)name >= VARNAME__MAX, "expected goto name");
+	ls->linenumber = ls->fs->bcbase[vg->startpc].line;
+	lj_assertLS(strref(vg->name) != NAME_BREAK, "unexpected break");
+	lj_lex_error(ls, 0, LJ_ERR_XGSCOPE,
+		     strdata(strref(vg->name)), strdata(name));
+}
+gola_patch(ls, vg, vl);
+}
+}
+/* Fixup remaining gotos and labels for scope. */
+static void gola_fixup(LexState *ls, FuncScope *bl)
+{
+VarInfo *v = ls->vstack + bl->vstart;
+VarInfo *ve = ls->vstack + ls->vtop;
+for (; v < ve; v++) {
+GCstr *name = strref(v->name);
+if (name != NULL) {  /* Only consider remaining valid gotos/labels. */
+if (gola_islabel(v)) {
+	VarInfo *vg;
+	setgcrefnull(v->name);  /* Invalidate label that goes out of scope. */
+	for (vg = v+1; vg < ve; vg++)  /* Resolve pending backward gotos. */
+	  if (strref(vg->name) == name && gola_isgoto(vg)) {
+	    if ((bl->flags&FSCOPE_UPVAL) && vg->slot > v->slot)
+	      gola_close(ls, vg);
+	    gola_patch(ls, vg, v);
+	  }
+} else if (gola_isgoto(v)) {
+	if (bl->prev) {  /* Propagate goto or break to outer scope. */
+	  bl->prev->flags |= name == NAME_BREAK ? FSCOPE_BREAK : FSCOPE_GOLA;
+	  v->slot = bl->nactvar;
+	  if ((bl->flags & FSCOPE_UPVAL))
+	    gola_close(ls, v);
+	} else {  /* No outer scope: undefined goto label or no loop. */
+	  ls->linenumber = ls->fs->bcbase[v->startpc].line;
+	  if (name == NAME_BREAK)
+	    lj_lex_error(ls, 0, LJ_ERR_XBREAK);
+	  else
+	    lj_lex_error(ls, 0, LJ_ERR_XLUNDEF, strdata(name));
+	}
+}
+}
+}
+}
+/* Find existing label. */
+static VarInfo *gola_findlabel(LexState *ls, GCstr *name)
+{
+VarInfo *v = ls->vstack + ls->fs->bl->vstart;
+VarInfo *ve = ls->vstack + ls->vtop;
+for (; v < ve; v++)
+if (strref(v->name) == name && gola_islabel(v))
+return v;
+return NULL;
+}
+/* -- Scope handling ------------------------------------------------------ */
+/* Begin a scope. */
+static void fscope_begin(FuncState *fs, FuncScope *bl, int flags)
+{
+bl->nactvar = (uint8_t)fs->nactvar;
+bl->flags = flags;
+bl->vstart = fs->ls->vtop;
+bl->prev = fs->bl;
+fs->bl = bl;
+lj_assertFS(fs->freereg == fs->nactvar, "bad regalloc");
+}
+/* End a scope. */
+static void fscope_end(FuncState *fs)
+{
+FuncScope *bl = fs->bl;
+LexState *ls = fs->ls;
+fs->bl = bl->prev;
+var_remove(ls, bl->nactvar);
+fs->freereg = fs->nactvar;
+lj_assertFS(bl->nactvar == fs->nactvar, "bad regalloc");
+if ((bl->flags & (FSCOPE_UPVAL|FSCOPE_NOCLOSE)) == FSCOPE_UPVAL)
+bcemit_AJ(fs, BC_UCLO, bl->nactvar, 0);
+if ((bl->flags & FSCOPE_BREAK)) {
+if ((bl->flags & FSCOPE_LOOP)) {
+MSize idx = gola_new(ls, NAME_BREAK, VSTACK_LABEL, fs->pc);
+ls->vtop = idx;  /* Drop break label immediately. */
+gola_resolve(ls, bl, idx);
+} else {  /* Need the fixup step to propagate the breaks. */
+gola_fixup(ls, bl);
+return;
+}
+}
+if ((bl->flags & FSCOPE_GOLA)) {
+gola_fixup(ls, bl);
+}
+}
+/* Mark scope as having an upvalue. */
+static void fscope_uvmark(FuncState *fs, BCReg level)
+{
+FuncScope *bl;
+for (bl = fs->bl; bl && bl->nactvar > level; bl = bl->prev)
+;
+if (bl)
+bl->flags |= FSCOPE_UPVAL;
+}
+/* -- Function state management ------------------------------------------- */
+/* Fixup bytecode for prototype. */
+static void fs_fixup_bc(FuncState *fs, GCproto *pt, BCIns *bc, MSize n)
+{
+BCInsLine *base = fs->bcbase;
+MSize i;
+pt->sizebc = n;
+bc[0] = BCINS_AD((fs->flags & PROTO_VARARG) ? BC_FUNCV : BC_FUNCF,
+		   fs->framesize, 0);
+for (i = 1; i < n; i++)
+bc[i] = base[i].ins;
+}
+/* Fixup upvalues for child prototype, step #2. */
+static void fs_fixup_uv2(FuncState *fs, GCproto *pt)
+{
+VarInfo *vstack = fs->ls->vstack;
+uint16_t *uv = proto_uv(pt);
+MSize i, n = pt->sizeuv;
+for (i = 0; i < n; i++) {
+VarIndex vidx = uv[i];
+if (vidx >= LJ_MAX_VSTACK)
+uv[i] = vidx - LJ_MAX_VSTACK;
+else if ((vstack[vidx].info & VSTACK_VAR_RW))
+uv[i] = vstack[vidx].slot | PROTO_UV_LOCAL;
+else
+uv[i] = vstack[vidx].slot | PROTO_UV_LOCAL | PROTO_UV_IMMUTABLE;
+}
+}
+/* Fixup constants for prototype. */
+static void fs_fixup_k(FuncState *fs, GCproto *pt, void *kptr)
+{
+GCtab *kt;
+TValue *array;
+Node *node;
+MSize i, hmask;
+checklimitgt(fs, fs->nkn, BCMAX_D+1, "constants");
+checklimitgt(fs, fs->nkgc, BCMAX_D+1, "constants");
+setmref(pt->k, kptr);
+pt->sizekn = fs->nkn;
+pt->sizekgc = fs->nkgc;
+kt = fs->kt;
+array = tvref(kt->array);
+for (i = 0; i < kt->asize; i++)
+if (tvhaskslot(&array[i])) {
+TValue *tv = &((TValue *)kptr)[tvkslot(&array[i])];
+if (LJ_DUALNUM)
+	setintV(tv, (int32_t)i);
+else
+	setnumV(tv, (lua_Number)i);
+}
+node = noderef(kt->node);
+hmask = kt->hmask;
+for (i = 0; i <= hmask; i++) {
+Node *n = &node[i];
+if (tvhaskslot(&n->val)) {
+ptrdiff_t kidx = (ptrdiff_t)tvkslot(&n->val);
+lj_assertFS(!tvisint(&n->key), "unexpected integer key");
+if (tvisnum(&n->key)) {
+	TValue *tv = &((TValue *)kptr)[kidx];
+	if (LJ_DUALNUM) {
+	  lua_Number nn = numV(&n->key);
+	  int32_t k = lj_num2int(nn);
+	  lj_assertFS(!tvismzero(&n->key), "unexpected -0 key");
+	  if ((lua_Number)k == nn)
+	    setintV(tv, k);
+	  else
+	    *tv = n->key;
+	} else {
+	  *tv = n->key;
+	}
+} else {
+	GCobj *o = gcV(&n->key);
+	setgcref(((GCRef *)kptr)[~kidx], o);
+	lj_gc_objbarrier(fs->L, pt, o);
+	if (tvisproto(&n->key))
+	  fs_fixup_uv2(fs, gco2pt(o));
+}
+}
+}
+}
+/* Fixup upvalues for prototype, step #1. */
+static void fs_fixup_uv1(FuncState *fs, GCproto *pt, uint16_t *uv)
+{
+setmref(pt->uv, uv);
+pt->sizeuv = fs->nuv;
+memcpy(uv, fs->uvtmp, fs->nuv*sizeof(VarIndex));
+}
+#ifndef LUAJIT_DISABLE_DEBUGINFO
+/* Prepare lineinfo for prototype. */
+static size_t fs_prep_line(FuncState *fs, BCLine numline)
+{
+return (fs->pc-1) << (numline < 256 ? 0 : numline < 65536 ? 1 : 2);
+}
+/* Fixup lineinfo for prototype. */
+static void fs_fixup_line(FuncState *fs, GCproto *pt,
+			  void *lineinfo, BCLine numline)
+{
+BCInsLine *base = fs->bcbase + 1;
+BCLine first = fs->linedefined;
+MSize i = 0, n = fs->pc-1;
+pt->firstline = fs->linedefined;
+pt->numline = numline;
+setmref(pt->lineinfo, lineinfo);
+if (LJ_LIKELY(numline < 256)) {
+uint8_t *li = (uint8_t *)lineinfo;
+do {
+BCLine delta = base[i].line - first;
+lj_assertFS(delta >= 0 && delta < 256, "bad line delta");
+li[i] = (uint8_t)delta;
+} while (++i < n);
+} else if (LJ_LIKELY(numline < 65536)) {
+uint16_t *li = (uint16_t *)lineinfo;
+do {
+BCLine delta = base[i].line - first;
+lj_assertFS(delta >= 0 && delta < 65536, "bad line delta");
+li[i] = (uint16_t)delta;
+} while (++i < n);
+} else {
+uint32_t *li = (uint32_t *)lineinfo;
+do {
+BCLine delta = base[i].line - first;
+lj_assertFS(delta >= 0, "bad line delta");
+li[i] = (uint32_t)delta;
+} while (++i < n);
+}
+}
+/* Prepare variable info for prototype. */
+static size_t fs_prep_var(LexState *ls, FuncState *fs, size_t *ofsvar)
+{
+VarInfo *vs =ls->vstack, *ve;
+MSize i, n;
+BCPos lastpc;
+lj_buf_reset(&ls->sb);  /* Copy to temp. string buffer. */
+/* Store upvalue names. */
+for (i = 0, n = fs->nuv; i < n; i++) {
+GCstr *s = strref(vs[fs->uvmap[i]].name);
+MSize len = s->len+1;
+char *p = lj_buf_more(&ls->sb, len);
+p = lj_buf_wmem(p, strdata(s), len);
+ls->sb.w = p;
+}
+*ofsvar = sbuflen(&ls->sb);
+lastpc = 0;
+/* Store local variable names and compressed ranges. */
+for (ve = vs + ls->vtop, vs += fs->vbase; vs < ve; vs++) {
+if (!gola_isgotolabel(vs)) {
+GCstr *s = strref(vs->name);
+BCPos startpc;
+char *p;
+if ((uintptr_t)s < VARNAME__MAX) {
+	p = lj_buf_more(&ls->sb, 1 + 2*5);
+	*p++ = (char)(uintptr_t)s;
+} else {
+	MSize len = s->len+1;
+	p = lj_buf_more(&ls->sb, len + 2*5);
+	p = lj_buf_wmem(p, strdata(s), len);
+}
+startpc = vs->startpc;
+p = lj_strfmt_wuleb128(p, startpc-lastpc);
+p = lj_strfmt_wuleb128(p, vs->endpc-startpc);
+ls->sb.w = p;
+lastpc = startpc;
+}
+}
+lj_buf_putb(&ls->sb, '\0');  /* Terminator for varinfo. */
+return sbuflen(&ls->sb);
+}
+/* Fixup variable info for prototype. */
+static void fs_fixup_var(LexState *ls, GCproto *pt, uint8_t *p, size_t ofsvar)
+{
+setmref(pt->uvinfo, p);
+setmref(pt->varinfo, (char *)p + ofsvar);
+memcpy(p, ls->sb.b, sbuflen(&ls->sb));  /* Copy from temp. buffer. */
+}
+#else
+/* Initialize with empty debug info, if disabled. */
+#define fs_prep_line(fs, numline)		(UNUSED(numline), 0)
+#define fs_fixup_line(fs, pt, li, numline) \
+pt->firstline = pt->numline = 0, setmref((pt)->lineinfo, NULL)
+#define fs_prep_var(ls, fs, ofsvar)		(UNUSED(ofsvar), 0)
+#define fs_fixup_var(ls, pt, p, ofsvar) \
+setmref((pt)->uvinfo, NULL), setmref((pt)->varinfo, NULL)
+#endif
+/* Check if bytecode op returns. */
+static int bcopisret(BCOp op)
+{
+switch (op) {
+case BC_CALLMT: case BC_CALLT:
+case BC_RETM: case BC_RET: case BC_RET0: case BC_RET1:
+return 1;
+default:
+return 0;
+}
+}
+/* Fixup return instruction for prototype. */
+static void fs_fixup_ret(FuncState *fs)
+{
+BCPos lastpc = fs->pc;
+if (lastpc <= fs->lasttarget || !bcopisret(bc_op(fs->bcbase[lastpc-1].ins))) {
+if ((fs->bl->flags & FSCOPE_UPVAL))
+bcemit_AJ(fs, BC_UCLO, 0, 0);
+bcemit_AD(fs, BC_RET0, 0, 1);  /* Need final return. */
+}
+fs->bl->flags |= FSCOPE_NOCLOSE;  /* Handled above. */
+fscope_end(fs);
+lj_assertFS(fs->bl == NULL, "bad scope nesting");
+/* May need to fixup returns encoded before first function was created. */
+if (fs->flags & PROTO_FIXUP_RETURN) {
+BCPos pc;
+for (pc = 1; pc < lastpc; pc++) {
+BCIns ins = fs->bcbase[pc].ins;
+BCPos offset;
+switch (bc_op(ins)) {
+case BC_CALLMT: case BC_CALLT:
+case BC_RETM: case BC_RET: case BC_RET0: case BC_RET1:
+	offset = bcemit_INS(fs, ins);  /* Copy original instruction. */
+	fs->bcbase[offset].line = fs->bcbase[pc].line;
+	offset = offset-(pc+1)+BCBIAS_J;
+	if (offset > BCMAX_D)
+	  err_syntax(fs->ls, LJ_ERR_XFIXUP);
+	/* Replace with UCLO plus branch. */
+	fs->bcbase[pc].ins = BCINS_AD(BC_UCLO, 0, offset);
+	break;
+case BC_FNEW:
+	return;  /* We're done. */
+default:
+	break;
+}
+}
+}
+}
+/* Finish a FuncState and return the new prototype. */
+static GCproto *fs_finish(LexState *ls, BCLine line)
+{
+lua_State *L = ls->L;
+FuncState *fs = ls->fs;
+BCLine numline = line - fs->linedefined;
+size_t sizept, ofsk, ofsuv, ofsli, ofsdbg, ofsvar;
+GCproto *pt;
+/* Apply final fixups. */
+fs_fixup_ret(fs);
+/* Calculate total size of prototype including all colocated arrays. */
+sizept = sizeof(GCproto) + fs->pc*sizeof(BCIns) + fs->nkgc*sizeof(GCRef);
+sizept = (sizept + sizeof(TValue)-1) & ~(sizeof(TValue)-1);
+ofsk = sizept; sizept += fs->nkn*sizeof(TValue);
+ofsuv = sizept; sizept += ((fs->nuv+1)&~1)*2;
+ofsli = sizept; sizept += fs_prep_line(fs, numline);
+ofsdbg = sizept; sizept += fs_prep_var(ls, fs, &ofsvar);
+/* Allocate prototype and initialize its fields. */
+pt = (GCproto *)lj_mem_newgco(L, (MSize)sizept);
+pt->gct = ~LJ_TPROTO;
+pt->sizept = (MSize)sizept;
+pt->trace = 0;
+pt->flags = (uint8_t)(fs->flags & ~(PROTO_HAS_RETURN|PROTO_FIXUP_RETURN));
+pt->numparams = fs->numparams;
+pt->framesize = fs->framesize;
+setgcref(pt->chunkname, obj2gco(ls->chunkname));
+/* Close potentially uninitialized gap between bc and kgc. */
+*(uint32_t *)((char *)pt + ofsk - sizeof(GCRef)*(fs->nkgc+1)) = 0;
+fs_fixup_bc(fs, pt, (BCIns *)((char *)pt + sizeof(GCproto)), fs->pc);
+fs_fixup_k(fs, pt, (void *)((char *)pt + ofsk));
+fs_fixup_uv1(fs, pt, (uint16_t *)((char *)pt + ofsuv));
+fs_fixup_line(fs, pt, (void *)((char *)pt + ofsli), numline);
+fs_fixup_var(ls, pt, (uint8_t *)((char *)pt + ofsdbg), ofsvar);
+lj_vmevent_send(L, BC,
+setprotoV(L, L->top++, pt);
+);
+L->top--;  /* Pop table of constants. */
+ls->vtop = fs->vbase;  /* Reset variable stack. */
+ls->fs = fs->prev;
+lj_assertL(ls->fs != NULL || ls->tok == TK_eof, "bad parser state");
+return pt;
+}
+/* Initialize a new FuncState. */
+static void fs_init(LexState *ls, FuncState *fs)
+{
+lua_State *L = ls->L;
+fs->prev = ls->fs; ls->fs = fs;  /* Append to list. */
+fs->ls = ls;
+fs->vbase = ls->vtop;
+fs->L = L;
+fs->pc = 0;
+fs->lasttarget = 0;
+fs->jpc = NO_JMP;
+fs->freereg = 0;
+fs->nkgc = 0;
+fs->nkn = 0;
+fs->nactvar = 0;
+fs->nuv = 0;
+fs->bl = NULL;
+fs->flags = 0;
+fs->framesize = 1;  /* Minimum frame size. */
+fs->kt = lj_tab_new(L, 0, 0);
+/* Anchor table of constants in stack to avoid being collected. */
+settabV(L, L->top, fs->kt);
+incr_top(L);
+}
+/* -- Expressions --------------------------------------------------------- */
+/* Forward declaration. */
+static void expr(LexState *ls, ExpDesc *v);
+/* Return string expression. */
+static void expr_str(LexState *ls, ExpDesc *e)
+{
+expr_init(e, VKSTR, 0);
+e->u.sval = lex_str(ls);
+}
+/* Return index expression. */
+static void expr_index(FuncState *fs, ExpDesc *t, ExpDesc *e)
+{
+/* Already called: expr_toval(fs, e). */
+t->k = VINDEXED;
+if (expr_isnumk(e)) {
+#if LJ_DUALNUM
+if (tvisint(expr_numtv(e))) {
+int32_t k = intV(expr_numtv(e));
+if (checku8(k)) {
+	t->u.s.aux = BCMAX_C+1+(uint32_t)k;  /* 256..511: const byte key */
+	return;
+}
+}
+#else
+lua_Number n = expr_numberV(e);
+int32_t k = lj_num2int(n);
+if (checku8(k) && n == (lua_Number)k) {
+t->u.s.aux = BCMAX_C+1+(uint32_t)k;  /* 256..511: const byte key */
+return;
+}
+#endif
+} else if (expr_isstrk(e)) {
+BCReg idx = const_str(fs, e);
+if (idx <= BCMAX_C) {
+t->u.s.aux = ~idx;  /* -256..-1: const string key */
+return;
+}
+}
+t->u.s.aux = expr_toanyreg(fs, e);  /* 0..255: register */
+}
+/* Parse index expression with named field. */
+static void expr_field(LexState *ls, ExpDesc *v)
+{
+FuncState *fs = ls->fs;
+ExpDesc key;
+expr_toanyreg(fs, v);
+lj_lex_next(ls);  /* Skip dot or colon. */
+expr_str(ls, &key);
+expr_index(fs, v, &key);
+}
+/* Parse index expression with brackets. */
+static void expr_bracket(LexState *ls, ExpDesc *v)
+{
+lj_lex_next(ls);  /* Skip '['. */
+expr(ls, v);
+expr_toval(ls->fs, v);
+lex_check(ls, ']');
+}
+/* Get value of constant expression. */
+static void expr_kvalue(FuncState *fs, TValue *v, ExpDesc *e)
+{
+UNUSED(fs);
+if (e->k <= VKTRUE) {
+setpriV(v, ~(uint32_t)e->k);
+} else if (e->k == VKSTR) {
+setgcVraw(v, obj2gco(e->u.sval), LJ_TSTR);
+} else {
+lj_assertFS(tvisnumber(expr_numtv(e)), "bad number constant");
+*v = *expr_numtv(e);
+}
+}
+/* Parse table constructor expression. */
+static void expr_table(LexState *ls, ExpDesc *e)
+{
+FuncState *fs = ls->fs;
+BCLine line = ls->linenumber;
+GCtab *t = NULL;
+int vcall = 0, needarr = 0, fixt = 0;
+uint32_t narr = 1;  /* First array index. */
+uint32_t nhash = 0;  /* Number of hash entries. */
+BCReg freg = fs->freereg;
+BCPos pc = bcemit_AD(fs, BC_TNEW, freg, 0);
+expr_init(e, VNONRELOC, freg);
+bcreg_reserve(fs, 1);
+freg++;
+lex_check(ls, '{');
+while (ls->tok != '}') {
+ExpDesc key, val;
+vcall = 0;
+if (ls->tok == '[') {
+expr_bracket(ls, &key);  /* Already calls expr_toval. */
+if (!expr_isk(&key)) expr_index(fs, e, &key);
+if (expr_isnumk(&key) && expr_numiszero(&key)) needarr = 1; else nhash++;
+lex_check(ls, '=');
+} else if ((ls->tok == TK_name || (!LJ_52 && ls->tok == TK_goto)) &&
+	       lj_lex_lookahead(ls) == '=') {
+expr_str(ls, &key);
+lex_check(ls, '=');
+nhash++;
+} else {
+expr_init(&key, VKNUM, 0);
+setintV(&key.u.nval, (int)narr);
+narr++;
+needarr = vcall = 1;
+}
+expr(ls, &val);
+if (expr_isk(&key) && key.k != VKNIL &&
+	(key.k == VKSTR || expr_isk_nojump(&val))) {
+TValue k, *v;
+if (!t) {  /* Create template table on demand. */
+	BCReg kidx;
+	t = lj_tab_new(fs->L, needarr ? narr : 0, hsize2hbits(nhash));
+	kidx = const_gc(fs, obj2gco(t), LJ_TTAB);
+	fs->bcbase[pc].ins = BCINS_AD(BC_TDUP, freg-1, kidx);
+}
+vcall = 0;
+expr_kvalue(fs, &k, &key);
+v = lj_tab_set(fs->L, t, &k);
+lj_gc_anybarriert(fs->L, t);
+if (expr_isk_nojump(&val)) {  /* Add const key/value to template table. */
+	expr_kvalue(fs, v, &val);
+} else {  /* Otherwise create dummy string key (avoids lj_tab_newkey). */
+	settabV(fs->L, v, t);  /* Preserve key with table itself as value. */
+	fixt = 1;   /* Fix this later, after all resizes. */
+	goto nonconst;
+}
+} else {
+nonconst:
+if (val.k != VCALL) { expr_toanyreg(fs, &val); vcall = 0; }
+if (expr_isk(&key)) expr_index(fs, e, &key);
+bcemit_store(fs, e, &val);
+}
+fs->freereg = freg;
+if (!lex_opt(ls, ',') && !lex_opt(ls, ';')) break;
+}
+lex_match(ls, '}', '{', line);
+if (vcall) {
+BCInsLine *ilp = &fs->bcbase[fs->pc-1];
+ExpDesc en;
+lj_assertFS(bc_a(ilp->ins) == freg &&
+		bc_op(ilp->ins) == (narr > 256 ? BC_TSETV : BC_TSETB),
+		"bad CALL code generation");
+expr_init(&en, VKNUM, 0);
+en.u.nval.u32.lo = narr-1;
+en.u.nval.u32.hi = 0x43300000;  /* Biased integer to avoid denormals. */
+if (narr > 256) { fs->pc--; ilp--; }
+ilp->ins = BCINS_AD(BC_TSETM, freg, const_num(fs, &en));
+setbc_b(&ilp[-1].ins, 0);
+}
+if (pc == fs->pc-1) {  /* Make expr relocable if possible. */
+e->u.s.info = pc;
+fs->freereg--;
+e->k = VRELOCABLE;
+} else {
+e->k = VNONRELOC;  /* May have been changed by expr_index. */
+}
+if (!t) {  /* Construct TNEW RD: hhhhhaaaaaaaaaaa. */
+BCIns *ip = &fs->bcbase[pc].ins;
+if (!needarr) narr = 0;
+else if (narr < 3) narr = 3;
+else if (narr > 0x7ff) narr = 0x7ff;
+setbc_d(ip, narr|(hsize2hbits(nhash)<<11));
+} else {
+if (needarr && t->asize < narr)
+lj_tab_reasize(fs->L, t, narr-1);
+if (fixt) {  /* Fix value for dummy keys in template table. */
+Node *node = noderef(t->node);
+uint32_t i, hmask = t->hmask;
+for (i = 0; i <= hmask; i++) {
+	Node *n = &node[i];
+	if (tvistab(&n->val)) {
+	  lj_assertFS(tabV(&n->val) == t, "bad dummy key in template table");
+	  setnilV(&n->val);  /* Turn value into nil. */
+	}
+}
+}
+lj_gc_check(fs->L);
+}
+}
+/* Parse function parameters. */
+static BCReg parse_params(LexState *ls, int needself)
+{
+FuncState *fs = ls->fs;
+BCReg nparams = 0;
+lex_check(ls, '(');
+if (needself)
+var_new_lit(ls, nparams++, "self");
+if (ls->tok != ')') {
+do {
+if (ls->tok == TK_name || (!LJ_52 && ls->tok == TK_goto)) {
+	var_new(ls, nparams++, lex_str(ls));
+} else if (ls->tok == TK_dots) {
+	lj_lex_next(ls);
+	fs->flags |= PROTO_VARARG;
+	break;
+} else {
+	err_syntax(ls, LJ_ERR_XPARAM);
+}
+} while (lex_opt(ls, ','));
+}
+var_add(ls, nparams);
+lj_assertFS(fs->nactvar == nparams, "bad regalloc");
+bcreg_reserve(fs, nparams);
+lex_check(ls, ')');
+return nparams;
+}
+/* Forward declaration. */
+static void parse_chunk(LexState *ls);
+/* Parse body of a function. */
+static void parse_body(LexState *ls, ExpDesc *e, int needself, BCLine line)
+{
+FuncState fs, *pfs = ls->fs;
+FuncScope bl;
+GCproto *pt;
+ptrdiff_t oldbase = pfs->bcbase - ls->bcstack;
+fs_init(ls, &fs);
+fscope_begin(&fs, &bl, 0);
+fs.linedefined = line;
+fs.numparams = (uint8_t)parse_params(ls, needself);
+fs.bcbase = pfs->bcbase + pfs->pc;
+fs.bclim = pfs->bclim - pfs->pc;
+bcemit_AD(&fs, BC_FUNCF, 0, 0);  /* Placeholder. */
+parse_chunk(ls);
+if (ls->tok != TK_end) lex_match(ls, TK_end, TK_function, line);
+pt = fs_finish(ls, (ls->lastline = ls->linenumber));
+pfs->bcbase = ls->bcstack + oldbase;  /* May have been reallocated. */
+pfs->bclim = (BCPos)(ls->sizebcstack - oldbase);
+/* Store new prototype in the constant array of the parent. */
+expr_init(e, VRELOCABLE,
+	    bcemit_AD(pfs, BC_FNEW, 0, const_gc(pfs, obj2gco(pt), LJ_TPROTO)));
+#if LJ_HASFFI
+pfs->flags |= (fs.flags & PROTO_FFI);
+#endif
+if (!(pfs->flags & PROTO_CHILD)) {
+if (pfs->flags & PROTO_HAS_RETURN)
+pfs->flags |= PROTO_FIXUP_RETURN;
+pfs->flags |= PROTO_CHILD;
+}
+lj_lex_next(ls);
+}
+/* Parse expression list. Last expression is left open. */
+static BCReg expr_list(LexState *ls, ExpDesc *v)
+{
+BCReg n = 1;
+expr(ls, v);
+while (lex_opt(ls, ',')) {
+expr_tonextreg(ls->fs, v);
+expr(ls, v);
+n++;
+}
+return n;
+}
+/* Parse function argument list. */
+static void parse_args(LexState *ls, ExpDesc *e)
+{
+FuncState *fs = ls->fs;
+ExpDesc args;
+BCIns ins;
+BCReg base;
+BCLine line = ls->linenumber;
+if (ls->tok == '(') {
+#if !LJ_52
+if (line != ls->lastline)
+err_syntax(ls, LJ_ERR_XAMBIG);
+#endif
+lj_lex_next(ls);
+if (ls->tok == ')') {  /* f(). */
+args.k = VVOID;
+} else {
+expr_list(ls, &args);
+if (args.k == VCALL)  /* f(a, b, g()) or f(a, b, ...). */
+	setbc_b(bcptr(fs, &args), 0);  /* Pass on multiple results. */
+}
+lex_match(ls, ')', '(', line);
+} else if (ls->tok == '{') {
+expr_table(ls, &args);
+} else if (ls->tok == TK_string) {
+expr_init(&args, VKSTR, 0);
+args.u.sval = strV(&ls->tokval);
+lj_lex_next(ls);
+} else {
+err_syntax(ls, LJ_ERR_XFUNARG);
+return;  /* Silence compiler. */
+}
+lj_assertFS(e->k == VNONRELOC, "bad expr type %d", e->k);
+base = e->u.s.info;  /* Base register for call. */
+if (args.k == VCALL) {
+ins = BCINS_ABC(BC_CALLM, base, 2, args.u.s.aux - base - 1 - LJ_FR2);
+} else {
+if (args.k != VVOID)
+expr_tonextreg(fs, &args);
+ins = BCINS_ABC(BC_CALL, base, 2, fs->freereg - base - LJ_FR2);
+}
+expr_init(e, VCALL, bcemit_INS(fs, ins));
+e->u.s.aux = base;
+fs->bcbase[fs->pc - 1].line = line;
+fs->freereg = base+1;  /* Leave one result by default. */
+}
+/* Parse primary expression. */
+static void expr_primary(LexState *ls, ExpDesc *v)
+{
+FuncState *fs = ls->fs;
+/* Parse prefix expression. */
+if (ls->tok == '(') {
+BCLine line = ls->linenumber;
+lj_lex_next(ls);
+expr(ls, v);
+lex_match(ls, ')', '(', line);
+expr_discharge(ls->fs, v);
+} else if (ls->tok == TK_name || (!LJ_52 && ls->tok == TK_goto)) {
+var_lookup(ls, v);
+} else {
+err_syntax(ls, LJ_ERR_XSYMBOL);
+}
+for (;;) {  /* Parse multiple expression suffixes. */
+if (ls->tok == '.') {
+expr_field(ls, v);
+} else if (ls->tok == '[') {
+ExpDesc key;
+expr_toanyreg(fs, v);
+expr_bracket(ls, &key);
+expr_index(fs, v, &key);
+} else if (ls->tok == ':') {
+ExpDesc key;
+lj_lex_next(ls);
+expr_str(ls, &key);
+bcemit_method(fs, v, &key);
+parse_args(ls, v);
+} else if (ls->tok == '(' || ls->tok == TK_string || ls->tok == '{') {
+expr_tonextreg(fs, v);
+if (LJ_FR2) bcreg_reserve(fs, 1);
+parse_args(ls, v);
+} else {
+break;
+}
+}
+}
+/* Parse simple expression. */
+static void expr_simple(LexState *ls, ExpDesc *v)
+{
+switch (ls->tok) {
+case TK_number:
+expr_init(v, (LJ_HASFFI && tviscdata(&ls->tokval)) ? VKCDATA : VKNUM, 0);
+copyTV(ls->L, &v->u.nval, &ls->tokval);
+break;
+case TK_string:
+expr_init(v, VKSTR, 0);
+v->u.sval = strV(&ls->tokval);
+break;
+case TK_nil:
+expr_init(v, VKNIL, 0);
+break;
+case TK_true:
+expr_init(v, VKTRUE, 0);
+break;
+case TK_false:
+expr_init(v, VKFALSE, 0);
+break;
+case TK_dots: {  /* Vararg. */
+FuncState *fs = ls->fs;
+BCReg base;
+checkcond(ls, fs->flags & PROTO_VARARG, LJ_ERR_XDOTS);
+bcreg_reserve(fs, 1);
+base = fs->freereg-1;
+expr_init(v, VCALL, bcemit_ABC(fs, BC_VARG, base, 2, fs->numparams));
+v->u.s.aux = base;
+break;
+}
+case '{':  /* Table constructor. */
+expr_table(ls, v);
+return;
+case TK_function:
+lj_lex_next(ls);
+parse_body(ls, v, 0, ls->linenumber);
+return;
+default:
+expr_primary(ls, v);
+return;
+}
+lj_lex_next(ls);
+}
+/* Manage syntactic levels to avoid blowing up the stack. */
+static void synlevel_begin(LexState *ls)
+{
+if (++ls->level >= LJ_MAX_XLEVEL)
+lj_lex_error(ls, 0, LJ_ERR_XLEVELS);
+}
+#define synlevel_end(ls)	((ls)->level--)
+/* Convert token to binary operator. */
+static BinOpr token2binop(LexToken tok)
+{
+switch (tok) {
+case '+':	return OPR_ADD;
+case '-':	return OPR_SUB;
+case '*':	return OPR_MUL;
+case '/':	return OPR_DIV;
+case '%':	return OPR_MOD;
+case '^':	return OPR_POW;
+case TK_concat: return OPR_CONCAT;
+case TK_ne:	return OPR_NE;
+case TK_eq:	return OPR_EQ;
+case '<':	return OPR_LT;
+case TK_le:	return OPR_LE;
+case '>':	return OPR_GT;
+case TK_ge:	return OPR_GE;
+case TK_and:	return OPR_AND;
+case TK_or:	return OPR_OR;
+default:	return OPR_NOBINOPR;
+}
+}
+/* Priorities for each binary operator. ORDER OPR. */
+static const struct {
+uint8_t left;		/* Left priority. */
+uint8_t right;	/* Right priority. */
+} priority[] = {
+{6,6}, {6,6}, {7,7}, {7,7}, {7,7},	/* ADD SUB MUL DIV MOD */
+{10,9}, {5,4},			/* POW CONCAT (right associative) */
+{3,3}, {3,3},				/* EQ NE */
+{3,3}, {3,3}, {3,3}, {3,3},		/* LT GE GT LE */
+{2,2}, {1,1}				/* AND OR */
+};
+#define UNARY_PRIORITY		8  /* Priority for unary operators. */
+/* Forward declaration. */
+static BinOpr expr_binop(LexState *ls, ExpDesc *v, uint32_t limit);
+/* Parse unary expression. */
+static void expr_unop(LexState *ls, ExpDesc *v)
+{
+BCOp op;
+if (ls->tok == TK_not) {
+op = BC_NOT;
+} else if (ls->tok == '-') {
+op = BC_UNM;
+} else if (ls->tok == '#') {
+op = BC_LEN;
+} else {
+expr_simple(ls, v);
+return;
+}
+lj_lex_next(ls);
+expr_binop(ls, v, UNARY_PRIORITY);
+bcemit_unop(ls->fs, op, v);
+}
+/* Parse binary expressions with priority higher than the limit. */
+static BinOpr expr_binop(LexState *ls, ExpDesc *v, uint32_t limit)
+{
+BinOpr op;
+synlevel_begin(ls);
+expr_unop(ls, v);
+op = token2binop(ls->tok);
+while (op != OPR_NOBINOPR && priority[op].left > limit) {
+ExpDesc v2;
+BinOpr nextop;
+lj_lex_next(ls);
+bcemit_binop_left(ls->fs, op, v);
+/* Parse binary expression with higher priority. */
+nextop = expr_binop(ls, &v2, priority[op].right);
+bcemit_binop(ls->fs, op, v, &v2);
+op = nextop;
+}
+synlevel_end(ls);
+return op;  /* Return unconsumed binary operator (if any). */
+}
+/* Parse expression. */
+static void expr(LexState *ls, ExpDesc *v)
+{
+expr_binop(ls, v, 0);  /* Priority 0: parse whole expression. */
+}
+/* Assign expression to the next register. */
+static void expr_next(LexState *ls)
+{
+ExpDesc e;
+expr(ls, &e);
+expr_tonextreg(ls->fs, &e);
+}
+/* Parse conditional expression. */
+static BCPos expr_cond(LexState *ls)
+{
+ExpDesc v;
+expr(ls, &v);
+if (v.k == VKNIL) v.k = VKFALSE;
+bcemit_branch_t(ls->fs, &v);
+return v.f;
+}
+/* -- Assignments --------------------------------------------------------- */
+/* List of LHS variables. */
+typedef struct LHSVarList {
+ExpDesc v;			/* LHS variable. */
+struct LHSVarList *prev;	/* Link to previous LHS variable. */
+} LHSVarList;
+/* Eliminate write-after-read hazards for local variable assignment. */
+static void assign_hazard(LexState *ls, LHSVarList *lh, const ExpDesc *v)
+{
+FuncState *fs = ls->fs;
+BCReg reg = v->u.s.info;  /* Check against this variable. */
+BCReg tmp = fs->freereg;  /* Rename to this temp. register (if needed). */
+int hazard = 0;
+for (; lh; lh = lh->prev) {
+if (lh->v.k == VINDEXED) {
+if (lh->v.u.s.info == reg) {  /* t[i], t = 1, 2 */
+	hazard = 1;
+	lh->v.u.s.info = tmp;
+}
+if (lh->v.u.s.aux == reg) {  /* t[i], i = 1, 2 */
+	hazard = 1;
+	lh->v.u.s.aux = tmp;
+}
+}
+}
+if (hazard) {
+bcemit_AD(fs, BC_MOV, tmp, reg);  /* Rename conflicting variable. */
+bcreg_reserve(fs, 1);
+}
+}
+/* Adjust LHS/RHS of an assignment. */
+static void assign_adjust(LexState *ls, BCReg nvars, BCReg nexps, ExpDesc *e)
+{
+FuncState *fs = ls->fs;
+int32_t extra = (int32_t)nvars - (int32_t)nexps;
+if (e->k == VCALL) {
+extra++;  /* Compensate for the VCALL itself. */
+if (extra < 0) extra = 0;
+setbc_b(bcptr(fs, e), extra+1);  /* Fixup call results. */
+if (extra > 1) bcreg_reserve(fs, (BCReg)extra-1);
+} else {
+if (e->k != VVOID)
+expr_tonextreg(fs, e);  /* Close last expression. */
+if (extra > 0) {  /* Leftover LHS are set to nil. */
+BCReg reg = fs->freereg;
+bcreg_reserve(fs, (BCReg)extra);
+bcemit_nil(fs, reg, (BCReg)extra);
+}
+}
+if (nexps > nvars)
+ls->fs->freereg -= nexps - nvars;  /* Drop leftover regs. */
+}
+/* Recursively parse assignment statement. */
+static void parse_assignment(LexState *ls, LHSVarList *lh, BCReg nvars)
+{
+ExpDesc e;
+checkcond(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED, LJ_ERR_XSYNTAX);
+if (lex_opt(ls, ',')) {  /* Collect LHS list and recurse upwards. */
+LHSVarList vl;
+vl.prev = lh;
+expr_primary(ls, &vl.v);
+if (vl.v.k == VLOCAL)
+assign_hazard(ls, lh, &vl.v);
+checklimit(ls->fs, ls->level + nvars, LJ_MAX_XLEVEL, "variable names");
+parse_assignment(ls, &vl, nvars+1);
+} else {  /* Parse RHS. */
+BCReg nexps;
+lex_check(ls, '=');
+nexps = expr_list(ls, &e);
+if (nexps == nvars) {
+if (e.k == VCALL) {
+	if (bc_op(*bcptr(ls->fs, &e)) == BC_VARG) {  /* Vararg assignment. */
+	  ls->fs->freereg--;
+	  e.k = VRELOCABLE;
+	} else {  /* Multiple call results. */
+	  e.u.s.info = e.u.s.aux;  /* Base of call is not relocatable. */
+	  e.k = VNONRELOC;
+	}
+}
+bcemit_store(ls->fs, &lh->v, &e);
+return;
+}
+assign_adjust(ls, nvars, nexps, &e);
+}
+/* Assign RHS to LHS and recurse downwards. */
+expr_init(&e, VNONRELOC, ls->fs->freereg-1);
+bcemit_store(ls->fs, &lh->v, &e);
+}
+/* Parse call statement or assignment. */
+static void parse_call_assign(LexState *ls)
+{
+FuncState *fs = ls->fs;
+LHSVarList vl;
+expr_primary(ls, &vl.v);
+if (vl.v.k == VCALL) {  /* Function call statement. */
+setbc_b(bcptr(fs, &vl.v), 1);  /* No results. */
+} else {  /* Start of an assignment. */
+vl.prev = NULL;
+parse_assignment(ls, &vl, 1);
+}
+}
+/* Parse 'local' statement. */
+static void parse_local(LexState *ls)
+{
+if (lex_opt(ls, TK_function)) {  /* Local function declaration. */
+ExpDesc v, b;
+FuncState *fs = ls->fs;
+var_new(ls, 0, lex_str(ls));
+expr_init(&v, VLOCAL, fs->freereg);
+v.u.s.aux = fs->varmap[fs->freereg];
+bcreg_reserve(fs, 1);
+var_add(ls, 1);
+parse_body(ls, &b, 0, ls->linenumber);
+/* bcemit_store(fs, &v, &b) without setting VSTACK_VAR_RW. */
+expr_free(fs, &b);
+expr_toreg(fs, &b, v.u.s.info);
+/* The upvalue is in scope, but the local is only valid after the store. */
+var_get(ls, fs, fs->nactvar - 1).startpc = fs->pc;
+} else {  /* Local variable declaration. */
+ExpDesc e;
+BCReg nexps, nvars = 0;
+do {  /* Collect LHS. */
+var_new(ls, nvars++, lex_str(ls));
+} while (lex_opt(ls, ','));
+if (lex_opt(ls, '=')) {  /* Optional RHS. */
+nexps = expr_list(ls, &e);
+} else {  /* Or implicitly set to nil. */
+e.k = VVOID;
+nexps = 0;
+}
+assign_adjust(ls, nvars, nexps, &e);
+var_add(ls, nvars);
+}
+}
+/* Parse 'function' statement. */
+static void parse_func(LexState *ls, BCLine line)
+{
+FuncState *fs;
+ExpDesc v, b;
+int needself = 0;
+lj_lex_next(ls);  /* Skip 'function'. */
+/* Parse function name. */
+var_lookup(ls, &v);
+while (ls->tok == '.')  /* Multiple dot-separated fields. */
+expr_field(ls, &v);
+if (ls->tok == ':') {  /* Optional colon to signify method call. */
+needself = 1;
+expr_field(ls, &v);
+}
+parse_body(ls, &b, needself, line);
+fs = ls->fs;
+bcemit_store(fs, &v, &b);
+fs->bcbase[fs->pc - 1].line = line;  /* Set line for the store. */
+}
+/* -- Control transfer statements ----------------------------------------- */
+/* Check for end of block. */
+static int parse_isend(LexToken tok)
+{
+switch (tok) {
+case TK_else: case TK_elseif: case TK_end: case TK_until: case TK_eof:
+return 1;
+default:
+return 0;
+}
+}
+/* Parse 'return' statement. */
+static void parse_return(LexState *ls)
+{
+BCIns ins;
+FuncState *fs = ls->fs;
+lj_lex_next(ls);  /* Skip 'return'. */
+fs->flags |= PROTO_HAS_RETURN;
+if (parse_isend(ls->tok) || ls->tok == ';') {  /* Bare return. */
+ins = BCINS_AD(BC_RET0, 0, 1);
+} else {  /* Return with one or more values. */
+ExpDesc e;  /* Receives the _last_ expression in the list. */
+BCReg nret = expr_list(ls, &e);
+if (nret == 1) {  /* Return one result. */
+if (e.k == VCALL) {  /* Check for tail call. */
+	BCIns *ip = bcptr(fs, &e);
+	/* It doesn't pay off to add BC_VARGT just for 'return ...'. */
+	if (bc_op(*ip) == BC_VARG) goto notailcall;
+	fs->pc--;
+	ins = BCINS_AD(bc_op(*ip)-BC_CALL+BC_CALLT, bc_a(*ip), bc_c(*ip));
+} else {  /* Can return the result from any register. */
+	ins = BCINS_AD(BC_RET1, expr_toanyreg(fs, &e), 2);
+}
+} else {
+if (e.k == VCALL) {  /* Append all results from a call. */
+notailcall:
+	setbc_b(bcptr(fs, &e), 0);
+	ins = BCINS_AD(BC_RETM, fs->nactvar, e.u.s.aux - fs->nactvar);
+} else {
+	expr_tonextreg(fs, &e);  /* Force contiguous registers. */
+	ins = BCINS_AD(BC_RET, fs->nactvar, nret+1);
+}
+}
+}
+if (fs->flags & PROTO_CHILD)
+bcemit_AJ(fs, BC_UCLO, 0, 0);  /* May need to close upvalues first. */
+bcemit_INS(fs, ins);
+}
+/* Parse 'break' statement. */
+static void parse_break(LexState *ls)
+{
+ls->fs->bl->flags |= FSCOPE_BREAK;
+gola_new(ls, NAME_BREAK, VSTACK_GOTO, bcemit_jmp(ls->fs));
+}
+/* Parse 'goto' statement. */
+static void parse_goto(LexState *ls)
+{
+FuncState *fs = ls->fs;
+GCstr *name = lex_str(ls);
+VarInfo *vl = gola_findlabel(ls, name);
+if (vl)  /* Treat backwards goto within same scope like a loop. */
+bcemit_AJ(fs, BC_LOOP, vl->slot, -1);  /* No BC range check. */
+fs->bl->flags |= FSCOPE_GOLA;
+gola_new(ls, name, VSTACK_GOTO, bcemit_jmp(fs));
+}
+/* Parse label. */
+static void parse_label(LexState *ls)
+{
+FuncState *fs = ls->fs;
+GCstr *name;
+MSize idx;
+fs->lasttarget = fs->pc;
+fs->bl->flags |= FSCOPE_GOLA;
+lj_lex_next(ls);  /* Skip '::'. */
+name = lex_str(ls);
+if (gola_findlabel(ls, name))
+lj_lex_error(ls, 0, LJ_ERR_XLDUP, strdata(name));
+idx = gola_new(ls, name, VSTACK_LABEL, fs->pc);
+lex_check(ls, TK_label);
+/* Recursively parse trailing statements: labels and ';' (Lua 5.2 only). */
+for (;;) {
+if (ls->tok == TK_label) {
+synlevel_begin(ls);
+parse_label(ls);
+synlevel_end(ls);
+} else if (LJ_52 && ls->tok == ';') {
+lj_lex_next(ls);
+} else {
+break;
+}
+}
+/* Trailing label is considered to be outside of scope. */
+if (parse_isend(ls->tok) && ls->tok != TK_until)
+ls->vstack[idx].slot = fs->bl->nactvar;
+gola_resolve(ls, fs->bl, idx);
+}
+/* -- Blocks, loops and conditional statements ---------------------------- */
+/* Parse a block. */
+static void parse_block(LexState *ls)
+{
+FuncState *fs = ls->fs;
+FuncScope bl;
+fscope_begin(fs, &bl, 0);
+parse_chunk(ls);
+fscope_end(fs);
+}
+/* Parse 'while' statement. */
+static void parse_while(LexState *ls, BCLine line)
+{
+FuncState *fs = ls->fs;
+BCPos start, loop, condexit;
+FuncScope bl;
+lj_lex_next(ls);  /* Skip 'while'. */
+start = fs->lasttarget = fs->pc;
+condexit = expr_cond(ls);
+fscope_begin(fs, &bl, FSCOPE_LOOP);
+lex_check(ls, TK_do);
+loop = bcemit_AD(fs, BC_LOOP, fs->nactvar, 0);
+parse_block(ls);
+jmp_patch(fs, bcemit_jmp(fs), start);
+lex_match(ls, TK_end, TK_while, line);
+fscope_end(fs);
+jmp_tohere(fs, condexit);
+jmp_patchins(fs, loop, fs->pc);
+}
+/* Parse 'repeat' statement. */
+static void parse_repeat(LexState *ls, BCLine line)
+{
+FuncState *fs = ls->fs;
+BCPos loop = fs->lasttarget = fs->pc;
+BCPos condexit;
+FuncScope bl1, bl2;
+fscope_begin(fs, &bl1, FSCOPE_LOOP);  /* Breakable loop scope. */
+fscope_begin(fs, &bl2, 0);  /* Inner scope. */
+lj_lex_next(ls);  /* Skip 'repeat'. */
+bcemit_AD(fs, BC_LOOP, fs->nactvar, 0);
+parse_chunk(ls);
+lex_match(ls, TK_until, TK_repeat, line);
+condexit = expr_cond(ls);  /* Parse condition (still inside inner scope). */
+if (!(bl2.flags & FSCOPE_UPVAL)) {  /* No upvalues? Just end inner scope. */
+fscope_end(fs);
+} else {  /* Otherwise generate: cond: UCLO+JMP out, !cond: UCLO+JMP loop. */
+parse_break(ls);  /* Break from loop and close upvalues. */
+jmp_tohere(fs, condexit);
+fscope_end(fs);  /* End inner scope and close upvalues. */
+condexit = bcemit_jmp(fs);
+}
+jmp_patch(fs, condexit, loop);  /* Jump backwards if !cond. */
+jmp_patchins(fs, loop, fs->pc);
+fscope_end(fs);  /* End loop scope. */
+}
+/* Parse numeric 'for'. */
+static void parse_for_num(LexState *ls, GCstr *varname, BCLine line)
+{
+FuncState *fs = ls->fs;
+BCReg base = fs->freereg;
+FuncScope bl;
+BCPos loop, loopend;
+/* Hidden control variables. */
+var_new_fixed(ls, FORL_IDX, VARNAME_FOR_IDX);
+var_new_fixed(ls, FORL_STOP, VARNAME_FOR_STOP);
+var_new_fixed(ls, FORL_STEP, VARNAME_FOR_STEP);
+/* Visible copy of index variable. */
+var_new(ls, FORL_EXT, varname);
+lex_check(ls, '=');
+expr_next(ls);
+lex_check(ls, ',');
+expr_next(ls);
+if (lex_opt(ls, ',')) {
+expr_next(ls);
+} else {
+bcemit_AD(fs, BC_KSHORT, fs->freereg, 1);  /* Default step is 1. */
+bcreg_reserve(fs, 1);
+}
+var_add(ls, 3);  /* Hidden control variables. */
+lex_check(ls, TK_do);
+loop = bcemit_AJ(fs, BC_FORI, base, NO_JMP);
+fscope_begin(fs, &bl, 0);  /* Scope for visible variables. */
+var_add(ls, 1);
+bcreg_reserve(fs, 1);
+parse_block(ls);
+fscope_end(fs);
+/* Perform loop inversion. Loop control instructions are at the end. */
+loopend = bcemit_AJ(fs, BC_FORL, base, NO_JMP);
+fs->bcbase[loopend].line = line;  /* Fix line for control ins. */
+jmp_patchins(fs, loopend, loop+1);
+jmp_patchins(fs, loop, fs->pc);
+}
+/* Try to predict whether the iterator is next() and specialize the bytecode.
+** Detecting next() and pairs() by name is simplistic, but quite effective.
+** The interpreter backs off if the check for the closure fails at runtime.
+*/
+static int predict_next(LexState *ls, FuncState *fs, BCPos pc)
+{
+BCIns ins = fs->bcbase[pc].ins;
+GCstr *name;
+cTValue *o;
+switch (bc_op(ins)) {
+case BC_MOV:
+if (bc_d(ins) >= fs->nactvar) return 0;
+name = gco2str(gcref(var_get(ls, fs, bc_d(ins)).name));
+break;
+case BC_UGET:
+name = gco2str(gcref(ls->vstack[fs->uvmap[bc_d(ins)]].name));
+break;
+case BC_GGET:
+/* There's no inverse index (yet), so lookup the strings. */
+o = lj_tab_getstr(fs->kt, lj_str_newlit(ls->L, "pairs"));
+if (o && tvhaskslot(o) && tvkslot(o) == bc_d(ins))
+return 1;
+o = lj_tab_getstr(fs->kt, lj_str_newlit(ls->L, "next"));
+if (o && tvhaskslot(o) && tvkslot(o) == bc_d(ins))
+return 1;
+return 0;
+default:
+return 0;
+}
+return (name->len == 5 && !strcmp(strdata(name), "pairs")) ||
+	 (name->len == 4 && !strcmp(strdata(name), "next"));
+}
+/* Parse 'for' iterator. */
+static void parse_for_iter(LexState *ls, GCstr *indexname)
+{
+FuncState *fs = ls->fs;
+ExpDesc e;
+BCReg nvars = 0;
+BCLine line;
+BCReg base = fs->freereg + 3;
+BCPos loop, loopend, exprpc = fs->pc;
+FuncScope bl;
+int isnext;
+/* Hidden control variables. */
+var_new_fixed(ls, nvars++, VARNAME_FOR_GEN);
+var_new_fixed(ls, nvars++, VARNAME_FOR_STATE);
+var_new_fixed(ls, nvars++, VARNAME_FOR_CTL);
+/* Visible variables returned from iterator. */
+var_new(ls, nvars++, indexname);
+while (lex_opt(ls, ','))
+var_new(ls, nvars++, lex_str(ls));
+lex_check(ls, TK_in);
+line = ls->linenumber;
+assign_adjust(ls, 3, expr_list(ls, &e), &e);
+/* The iterator needs another 3 [4] slots (func [pc] | state ctl). */
+bcreg_bump(fs, 3+LJ_FR2);
+isnext = (nvars <= 5 && predict_next(ls, fs, exprpc));
+var_add(ls, 3);  /* Hidden control variables. */
+lex_check(ls, TK_do);
+loop = bcemit_AJ(fs, isnext ? BC_ISNEXT : BC_JMP, base, NO_JMP);
+fscope_begin(fs, &bl, 0);  /* Scope for visible variables. */
+var_add(ls, nvars-3);
+bcreg_reserve(fs, nvars-3);
+parse_block(ls);
+fscope_end(fs);
+/* Perform loop inversion. Loop control instructions are at the end. */
+jmp_patchins(fs, loop, fs->pc);
+bcemit_ABC(fs, isnext ? BC_ITERN : BC_ITERC, base, nvars-3+1, 2+1);
+loopend = bcemit_AJ(fs, BC_ITERL, base, NO_JMP);
+fs->bcbase[loopend-1].line = line;  /* Fix line for control ins. */
+fs->bcbase[loopend].line = line;
+jmp_patchins(fs, loopend, loop+1);
+}
+/* Parse 'for' statement. */
+static void parse_for(LexState *ls, BCLine line)
+{
+FuncState *fs = ls->fs;
+GCstr *varname;
+FuncScope bl;
+fscope_begin(fs, &bl, FSCOPE_LOOP);
+lj_lex_next(ls);  /* Skip 'for'. */
+varname = lex_str(ls);  /* Get first variable name. */
+if (ls->tok == '=')
+parse_for_num(ls, varname, line);
+else if (ls->tok == ',' || ls->tok == TK_in)
+parse_for_iter(ls, varname);
+else
+err_syntax(ls, LJ_ERR_XFOR);
+lex_match(ls, TK_end, TK_for, line);
+fscope_end(fs);  /* Resolve break list. */
+}
+/* Parse condition and 'then' block. */
+static BCPos parse_then(LexState *ls)
+{
+BCPos condexit;
+lj_lex_next(ls);  /* Skip 'if' or 'elseif'. */
+condexit = expr_cond(ls);
+lex_check(ls, TK_then);
+parse_block(ls);
+return condexit;
+}
+/* Parse 'if' statement. */
+static void parse_if(LexState *ls, BCLine line)
+{
+FuncState *fs = ls->fs;
+BCPos flist;
+BCPos escapelist = NO_JMP;
+flist = parse_then(ls);
+while (ls->tok == TK_elseif) {  /* Parse multiple 'elseif' blocks. */
+jmp_append(fs, &escapelist, bcemit_jmp(fs));
+jmp_tohere(fs, flist);
+flist = parse_then(ls);
+}
+if (ls->tok == TK_else) {  /* Parse optional 'else' block. */
+jmp_append(fs, &escapelist, bcemit_jmp(fs));
+jmp_tohere(fs, flist);
+lj_lex_next(ls);  /* Skip 'else'. */
+parse_block(ls);
+} else {
+jmp_append(fs, &escapelist, flist);
+}
+jmp_tohere(fs, escapelist);
+lex_match(ls, TK_end, TK_if, line);
+}
+/* -- Parse statements ---------------------------------------------------- */
+/* Parse a statement. Returns 1 if it must be the last one in a chunk. */
+static int parse_stmt(LexState *ls)
+{
+BCLine line = ls->linenumber;
+switch (ls->tok) {
+case TK_if:
+parse_if(ls, line);
+break;
+case TK_while:
+parse_while(ls, line);
+break;
+case TK_do:
+lj_lex_next(ls);
+parse_block(ls);
+lex_match(ls, TK_end, TK_do, line);
+break;
+case TK_for:
+parse_for(ls, line);
+break;
+case TK_repeat:
+parse_repeat(ls, line);
+break;
+case TK_function:
+parse_func(ls, line);
+break;
+case TK_local:
+lj_lex_next(ls);
+parse_local(ls);
+break;
+case TK_return:
+parse_return(ls);
+return 1;  /* Must be last. */
+case TK_break:
+lj_lex_next(ls);
+parse_break(ls);
+return !LJ_52;  /* Must be last in Lua 5.1. */
+#if LJ_52
+case ';':
+lj_lex_next(ls);
+break;
+#endif
+case TK_label:
+parse_label(ls);
+break;
+case TK_goto:
+if (LJ_52 || lj_lex_lookahead(ls) == TK_name) {
+lj_lex_next(ls);
+parse_goto(ls);
+break;
+}
+/* fallthrough */
+default:
+parse_call_assign(ls);
+break;
+}
+return 0;
+}
+/* A chunk is a list of statements optionally separated by semicolons. */
+static void parse_chunk(LexState *ls)
+{
+int islast = 0;
+synlevel_begin(ls);
+while (!islast && !parse_isend(ls->tok)) {
+islast = parse_stmt(ls);
+lex_opt(ls, ';');
+lj_assertLS(ls->fs->framesize >= ls->fs->freereg &&
+		ls->fs->freereg >= ls->fs->nactvar,
+		"bad regalloc");
+ls->fs->freereg = ls->fs->nactvar;  /* Free registers after each stmt. */
+}
+synlevel_end(ls);
+}
+/* Entry point of bytecode parser. */
+GCproto *lj_parse(LexState *ls)
+{
+FuncState fs;
+FuncScope bl;
+GCproto *pt;
+lua_State *L = ls->L;
+#ifdef LUAJIT_DISABLE_DEBUGINFO
+ls->chunkname = lj_str_newlit(L, "=");
+#else
+ls->chunkname = lj_str_newz(L, ls->chunkarg);
+#endif
+setstrV(L, L->top, ls->chunkname);  /* Anchor chunkname string. */
+incr_top(L);
+ls->level = 0;
+fs_init(ls, &fs);
+fs.linedefined = 0;
+fs.numparams = 0;
+fs.bcbase = NULL;
+fs.bclim = 0;
+fs.flags |= PROTO_VARARG;  /* Main chunk is always a vararg func. */
+fscope_begin(&fs, &bl, 0);
+bcemit_AD(&fs, BC_FUNCV, 0, 0);  /* Placeholder. */
+lj_lex_next(ls);  /* Read-ahead first token. */
+parse_chunk(ls);
+if (ls->tok != TK_eof)
+err_token(ls, TK_eof);
+pt = fs_finish(ls, ls->linenumber);
+L->top--;  /* Drop chunkname. */
+lj_assertL(fs.prev == NULL && ls->fs == NULL, "mismatched frame nesting");
+lj_assertL(pt->sizeuv == 0, "toplevel proto has upvalues");
+return pt;
+}

Mercurial

comparison third_party/luajit/src/lj_parse.c @ 186:8cf4ec5e2191 hg-web