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lj_parse.c
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/*
** Lua parser (source code -> bytecode).
** Copyright (C) 2005-2021 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)