/*
** Lua parser (source code -> bytecode).
** Copyright (C) 2005-2020 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);
int64_t *p = (int64_t *)cdataptr(cd);
if (cd->ctypeid == CTID_COMPLEX_DOUBLE)
p[1] ^= (int64_t)U64x(80000000,00000000);
else
*p = -*p;
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);
if (k == -k)
setnumV(o, -(lua_Number)k);
else
setintV(o, -k);
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);
setsbufP(&ls->sb, 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);
setsbufP(&ls->sb, 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, sbufB(&ls->sb), 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_UCLO:
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:
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;
}