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lua/lcode.c

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/*
** $Id: lcode.c,v 1.95 2002/04/09 18:49:30 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#include "lua.h"
#include "lcode.h"
#include "ldebug.h"
#include "ldo.h"
#include "llex.h"
#include "lmem.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lparser.h"
#include "ltable.h"
#define hasjumps(e) ((e)->t != (e)->f)
void luaK_error (LexState *ls, const char *msg) {
luaX_error(ls, msg, ls->t.token);
}
void luaK_nil (FuncState *fs, int from, int n) {
Instruction *previous;
if (fs->pc > fs->lasttarget && /* no jumps to current position? */
GET_OPCODE(*(previous = &fs->f->code[fs->pc-1])) == OP_LOADNIL) {
int pfrom = GETARG_A(*previous);
int pto = GETARG_B(*previous);
if (pfrom <= from && from <= pto+1) { /* can connect both? */
if (from+n-1 > pto)
SETARG_B(*previous, from+n-1);
return;
}
}
luaK_codeABC(fs, OP_LOADNIL, from, from+n-1, 0); /* else no optimization */
}
int luaK_jump (FuncState *fs) {
int j = luaK_codeAsBc(fs, OP_JMP, 0, NO_JUMP);
if (j == fs->lasttarget) { /* possible jumps to this jump? */
luaK_concat(fs, &j, fs->jlt); /* keep them on hold */
fs->jlt = NO_JUMP;
}
return j;
}
static int luaK_condjump (FuncState *fs, OpCode op, int A, int B, int C) {
luaK_codeABC(fs, op, A, B, C);
return luaK_codeAsBc(fs, OP_JMP, 0, NO_JUMP);
}
static void luaK_fixjump (FuncState *fs, int pc, int dest) {
Instruction *jmp = &fs->f->code[pc];
if (dest == NO_JUMP)
SETARG_sBc(*jmp, NO_JUMP); /* point to itself to represent end of list */
else { /* jump is relative to position following jump instruction */
int offset = dest-(pc+1);
if (abs(offset) > MAXARG_sBc)
luaK_error(fs->ls, "control structure too long");
SETARG_sBc(*jmp, offset);
}
}
/*
** returns current `pc' and marks it as a jump target (to avoid wrong
** optimizations with consecutive instructions not in the same basic block).
** discharge list of jumps to last target.
*/
int luaK_getlabel (FuncState *fs) {
if (fs->pc != fs->lasttarget) {
int lasttarget = fs->lasttarget;
fs->lasttarget = fs->pc;
luaK_patchlist(fs, fs->jlt, lasttarget); /* discharge old list `jlt' */
fs->jlt = NO_JUMP; /* nobody jumps to this new label (yet) */
}
return fs->pc;
}
static int luaK_getjump (FuncState *fs, int pc) {
int offset = GETARG_sBc(fs->f->code[pc]);
if (offset == NO_JUMP) /* point to itself represents end of list */
return NO_JUMP; /* end of list */
else
return (pc+1)+offset; /* turn offset into absolute position */
}
static Instruction *getjumpcontrol (FuncState *fs, int pc) {
Instruction *pi = &fs->f->code[pc];
if (pc >= 1 && testOpMode(GET_OPCODE(*(pi-1)), OpModeT))
return pi-1;
else
return pi;
}
static int need_value (FuncState *fs, int list, OpCode op) {
/* check whether list has any jump different from `op' */
for (; list != NO_JUMP; list = luaK_getjump(fs, list))
if (GET_OPCODE(*getjumpcontrol(fs, list)) != op) return 1;
return 0; /* not found */
}
static void patchtestreg (Instruction *i, int reg) {
if (reg == NO_REG) reg = GETARG_B(*i);
SETARG_A(*i, reg);
}
static void luaK_patchlistaux (FuncState *fs, int list,
int ttarget, int treg, int ftarget, int freg, int dtarget) {
while (list != NO_JUMP) {
int next = luaK_getjump(fs, list);
Instruction *i = getjumpcontrol(fs, list);
switch (GET_OPCODE(*i)) {
case OP_TESTT: {
patchtestreg(i, treg);
luaK_fixjump(fs, list, ttarget);
break;
}
case OP_TESTF: {
patchtestreg(i, freg);
luaK_fixjump(fs, list, ftarget);
break;
}
default: {
luaK_fixjump(fs, list, dtarget); /* jump to default target */
break;
}
}
list = next;
}
}
void luaK_patchlist (FuncState *fs, int list, int target) {
if (target == fs->lasttarget) /* same target that list `jlt'? */
luaK_concat(fs, &fs->jlt, list); /* delay fixing */
else
luaK_patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
}
void luaK_patchtohere (FuncState *fs, int list) {
luaK_patchlist(fs, list, luaK_getlabel(fs));
}
void luaK_concat (FuncState *fs, int *l1, int l2) {
if (*l1 == NO_JUMP)
*l1 = l2;
else {
int list = *l1;
int next;
while ((next = luaK_getjump(fs, list)) != NO_JUMP) /* find last element */
list = next;
luaK_fixjump(fs, list, l2);
}
}
static void luaK_checkstack (FuncState *fs, int n) {
int newstack = fs->freereg + n;
if (newstack > fs->f->maxstacksize) {
if (newstack >= MAXSTACK)
luaK_error(fs->ls, "function or expression too complex");
fs->f->maxstacksize = cast(lu_byte, newstack);
}
}
void luaK_reserveregs (FuncState *fs, int n) {
luaK_checkstack(fs, n);
fs->freereg += n;
}
static void freereg (FuncState *fs, int reg) {
if (reg >= fs->nactloc && reg < MAXSTACK) {
fs->freereg--;
lua_assert(reg == fs->freereg);
}
}
static void freeexp (FuncState *fs, expdesc *e) {
if (e->k == VNONRELOC)
freereg(fs, e->info);
}
static int addk (FuncState *fs, TObject *k, TObject *v) {
const TObject *index = luaH_get(fs->h, k);
if (ttype(index) == LUA_TNUMBER) {
lua_assert(luaO_equalObj(&fs->f->k[cast(int, nvalue(index))], v));
return cast(int, nvalue(index));
}
else { /* constant not found; create a new entry */
TObject o;
Proto *f = fs->f;
luaM_growvector(fs->L, f->k, fs->nk, f->sizek, TObject,
MAXARG_Bc, "constant table overflow");
setobj(&f->k[fs->nk], v);
setnvalue(&o, fs->nk);
luaH_set(fs->L, fs->h, k, &o);
return fs->nk++;
}
}
int luaK_stringK (FuncState *fs, TString *s) {
TObject o;
setsvalue(&o, s);
return addk(fs, &o, &o);
}
int luaK_numberK (FuncState *fs, lua_Number r) {
TObject o;
setnvalue(&o, r);
return addk(fs, &o, &o);
}
static int nil_constant (FuncState *fs) {
TObject k, v;
setnilvalue(&v);
sethvalue(&k, fs->h); /* cannot use nil as key; instead use table itself */
return addk(fs, &k, &v);
}
void luaK_setcallreturns (FuncState *fs, expdesc *e, int nresults) {
if (e->k == VCALL) { /* expression is an open function call? */
SETARG_C(getcode(fs, e), nresults+1);
if (nresults == 1) { /* `regular' expression? */
e->k = VNONRELOC;
e->info = GETARG_A(getcode(fs, e));
}
}
}
void luaK_dischargevars (FuncState *fs, expdesc *e) {
switch (e->k) {
case VLOCAL: {
e->k = VNONRELOC;
break;
}
case VUPVAL: {
e->info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->info, 0);
e->k = VRELOCABLE;
break;
}
case VGLOBAL: {
e->info = luaK_codeABc(fs, OP_GETGLOBAL, 0, e->info);
e->k = VRELOCABLE;
break;
}
case VINDEXED: {
freereg(fs, e->aux);
freereg(fs, e->info);
e->info = luaK_codeABC(fs, OP_GETTABLE, 0, e->info, e->aux);
e->k = VRELOCABLE;
break;
}
case VCALL: {
luaK_setcallreturns(fs, e, 1);
break;
}
default: break; /* there is one value available (somewhere) */
}
}
static int code_label (FuncState *fs, int A, int b, int jump) {
luaK_getlabel(fs); /* those instructions may be jump targets */
return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
}
static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
luaK_dischargevars(fs, e);
switch (e->k) {
case VNIL: {
luaK_nil(fs, reg, 1);
break;
}
case VFALSE: case VTRUE: {
luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
break;
}
case VK: {
luaK_codeABc(fs, OP_LOADK, reg, e->info);
break;
}
case VRELOCABLE: {
Instruction *pc = &getcode(fs, e);
SETARG_A(*pc, reg);
break;
}
case VNONRELOC: {
if (reg != e->info)
luaK_codeABC(fs, OP_MOVE, reg, e->info, 0);
break;
}
default: {
lua_assert(e->k == VVOID || e->k == VJMP);
return; /* nothing to do... */
}
}
e->info = reg;
e->k = VNONRELOC;
}
static void discharge2anyreg (FuncState *fs, expdesc *e) {
if (e->k != VNONRELOC) {
luaK_reserveregs(fs, 1);
discharge2reg(fs, e, fs->freereg-1);
}
}
static void luaK_exp2reg (FuncState *fs, expdesc *e, int reg) {
discharge2reg(fs, e, reg);
if (e->k == VJMP || hasjumps(e)) {
int final; /* position after whole expression */
int p_f = NO_JUMP; /* position of an eventual PUSH false */
int p_t = NO_JUMP; /* position of an eventual PUSH true */
if (e->k == VJMP || need_value(fs, e->f, OP_TESTF) ||
need_value(fs, e->t, OP_TESTT)) {
/* expression needs values */
if (e->k != VJMP) {
luaK_getlabel(fs); /* these instruction may be jump target */
luaK_codeAsBc(fs, OP_JMP, 0, 2); /* to jump over both pushes */
}
else { /* last expression is a conditional (test + jump) */
fs->pc--; /* remove its jump */
lua_assert(testOpMode(GET_OPCODE(fs->f->code[fs->pc - 1]), OpModeT));
}
p_t = code_label(fs, reg, 1, 1);
p_f = code_label(fs, reg, 0, 0);
}
final = luaK_getlabel(fs);
luaK_patchlistaux(fs, e->f, p_f, NO_REG, final, reg, p_f);
luaK_patchlistaux(fs, e->t, final, reg, p_t, NO_REG, p_t);
}
e->f = e->t = NO_JUMP;
e->info = reg;
e->k = VNONRELOC;
}
void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
luaK_dischargevars(fs, e);
freeexp(fs, e);
luaK_reserveregs(fs, 1);
luaK_exp2reg(fs, e, fs->freereg - 1);
}
int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
luaK_dischargevars(fs, e);
if (e->k == VNONRELOC) {
if (!hasjumps(e)) return e->info; /* exp is already in a register */
if (e->info >= fs->nactloc) { /* reg. is not a local? */
luaK_exp2reg(fs, e, e->info); /* put value on it */
return e->info;
}
}
luaK_exp2nextreg(fs, e); /* default */
return e->info;
}
void luaK_exp2val (FuncState *fs, expdesc *e) {
if (hasjumps(e))
luaK_exp2anyreg(fs, e);
else
luaK_dischargevars(fs, e);
}
int luaK_exp2RK (FuncState *fs, expdesc *e) {
luaK_exp2val(fs, e);
switch (e->k) {
case VNIL: {
if (fs->nk + MAXSTACK <= MAXARG_C) { /* constant fit in argC? */
e->info = nil_constant(fs);
e->k = VK;
return e->info + MAXSTACK;
}
else break;
}
case VK: {
if (e->info + MAXSTACK <= MAXARG_C) /* constant fit in argC? */
return e->info + MAXSTACK;
else break;
}
default: break;
}
/* not a constant in the right range: put in a register */
return luaK_exp2anyreg(fs, e);
}
void luaK_storevar (FuncState *fs, expdesc *var, expdesc *exp) {
switch (var->k) {
case VLOCAL: {
freeexp(fs, exp);
luaK_exp2reg(fs, exp, var->info);
return;
}
case VUPVAL: {
int e = luaK_exp2anyreg(fs, exp);
luaK_codeABC(fs, OP_SETUPVAL, e, var->info, 0);
break;
}
case VGLOBAL: {
int e = luaK_exp2anyreg(fs, exp);
luaK_codeABc(fs, OP_SETGLOBAL, e, var->info);
break;
}
case VINDEXED: {
int e = luaK_exp2anyreg(fs, exp);
luaK_codeABC(fs, OP_SETTABLE, e, var->info, var->aux);
break;
}
default: {
lua_assert(0); /* invalid var kind to store */
break;
}
}
freeexp(fs, exp);
}
void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
int func;
luaK_exp2anyreg(fs, e);
freeexp(fs, e);
func = fs->freereg;
luaK_reserveregs(fs, 2);
luaK_codeABC(fs, OP_SELF, func, e->info, luaK_exp2RK(fs, key));
freeexp(fs, key);
e->info = func;
e->k = VNONRELOC;
}
static OpCode invertoperator (OpCode op) {
switch (op) {
case OP_TESTNE: return OP_TESTEQ;
case OP_TESTEQ: return OP_TESTNE;
case OP_TESTLT: return OP_TESTGE;
case OP_TESTLE: return OP_TESTGT;
case OP_TESTGT: return OP_TESTLE;
case OP_TESTGE: return OP_TESTLT;
case OP_TESTT: return OP_TESTF;
case OP_TESTF: return OP_TESTT;
default: lua_assert(0); return op; /* invalid jump instruction */
}
}
static void invertjump (FuncState *fs, expdesc *e) {
Instruction *pc = getjumpcontrol(fs, e->info);
SET_OPCODE(*pc, invertoperator(GET_OPCODE(*pc)));
}
static int jumponcond (FuncState *fs, expdesc *e, OpCode op) {
if (e->k == VRELOCABLE) {
Instruction ie = getcode(fs, e);
if (GET_OPCODE(ie) == OP_NOT) {
op = invertoperator(op);
fs->pc--; /* remove previous OP_NOT */
return luaK_condjump(fs, op, NO_REG, GETARG_B(ie), 0);
}
/* else go through */
}
discharge2anyreg(fs, e);
freeexp(fs, e);
return luaK_condjump(fs, op, NO_REG, e->info, 0);
}
void luaK_goiftrue (FuncState *fs, expdesc *e) {
int pc; /* pc of last jump */
luaK_dischargevars(fs, e);
switch (e->k) {
case VK: case VTRUE: {
pc = NO_JUMP; /* always true; do nothing */
break;
}
case VFALSE: {
pc = luaK_codeAsBc(fs, OP_JMP, 0, NO_JUMP); /* always jump */
break;
}
case VJMP: {
invertjump(fs, e);
pc = e->info;
break;
}
default: {
pc = jumponcond(fs, e, OP_TESTF);
break;
}
}
luaK_concat(fs, &e->f, pc); /* insert last jump in `f' list */
luaK_patchtohere(fs, e->t);
e->t = NO_JUMP;
}
static void luaK_goiffalse (FuncState *fs, expdesc *e) {
int pc; /* pc of last jump */
luaK_dischargevars(fs, e);
switch (e->k) {
case VNIL: case VFALSE: {
pc = NO_JUMP; /* always false; do nothing */
break;
}
case VTRUE: {
pc = luaK_codeAsBc(fs, OP_JMP, 0, NO_JUMP); /* always jump */
break;
}
case VJMP: {
pc = e->info;
break;
}
default: {
pc = jumponcond(fs, e, OP_TESTT);
break;
}
}
luaK_concat(fs, &e->t, pc); /* insert last jump in `t' list */
luaK_patchtohere(fs, e->f);
e->f = NO_JUMP;
}
static void codenot (FuncState *fs, expdesc *e) {
luaK_dischargevars(fs, e);
switch (e->k) {
case VNIL: case VFALSE: {
e->k = VTRUE;
break;
}
case VK: case VTRUE: {
e->k = VFALSE;
break;
}
case VJMP: {
invertjump(fs, e);
break;
}
case VRELOCABLE:
case VNONRELOC: {
discharge2anyreg(fs, e);
freeexp(fs, e);
e->info = luaK_codeABC(fs, OP_NOT, 0, e->info, 0);
e->k = VRELOCABLE;
break;
}
default: {
lua_assert(0); /* cannot happen */
break;
}
}
/* interchange true and false lists */
{ int temp = e->f; e->f = e->t; e->t = temp; }
}
void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
t->aux = luaK_exp2RK(fs, k);
t->k = VINDEXED;
}
void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e) {
if (op == OPR_MINUS) {
luaK_exp2val(fs, e);
if (e->k == VK && ttype(&fs->f->k[e->info]) == LUA_TNUMBER)
e->info = luaK_numberK(fs, -nvalue(&fs->f->k[e->info]));
else {
luaK_exp2anyreg(fs, e);
freeexp(fs, e);
e->info = luaK_codeABC(fs, OP_UNM, 0, e->info, 0);
e->k = VRELOCABLE;
}
}
else /* op == NOT */
codenot(fs, e);
}
void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
switch (op) {
case OPR_AND: {
luaK_goiftrue(fs, v);
break;
}
case OPR_OR: {
luaK_goiffalse(fs, v);
break;
}
case OPR_CONCAT: {
luaK_exp2nextreg(fs, v); /* operand must be on the `stack' */
break;
}
case OPR_SUB: case OPR_DIV: case OPR_POW: {
/* non-comutative operators */
luaK_exp2anyreg(fs, v); /* first operand must be a register */
break;
}
default: {
luaK_exp2RK(fs, v);
break;
}
}
}
/* opcode for each binary operator */
static const OpCode codes[] = { /* ORDER OPR */
OP_ADD, OP_SUB, OP_MUL, OP_DIV,
OP_POW, OP_CONCAT,
OP_TESTNE, OP_TESTEQ,
OP_TESTLT, OP_TESTLE, OP_TESTGT, OP_TESTGE
};
/* `inverted' opcode for each binary operator */
/* ( -1 means operator has no inverse) */
static const OpCode invcodes[] = { /* ORDER OPR */
OP_ADD, (OpCode)-1, OP_MUL, (OpCode)-1,
(OpCode)-1, (OpCode)-1,
OP_TESTNE, OP_TESTEQ,
OP_TESTGT, OP_TESTGE, OP_TESTLT, OP_TESTLE
};
void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
switch (op) {
case OPR_AND: {
lua_assert(e1->t == NO_JUMP); /* list must be closed */
luaK_dischargevars(fs, e2);
luaK_concat(fs, &e1->f, e2->f);
e1->k = e2->k; e1->info = e2->info; e1->aux = e2->aux; e1->t = e2->t;
break;
}
case OPR_OR: {
lua_assert(e1->f == NO_JUMP); /* list must be closed */
luaK_dischargevars(fs, e2);
luaK_concat(fs, &e1->t, e2->t);
e1->k = e2->k; e1->info = e2->info; e1->aux = e2->aux; e1->f = e2->f;
break;
}
case OPR_CONCAT: {
luaK_exp2val(fs, e2);
if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
lua_assert(e1->info == GETARG_B(getcode(fs, e2))-1);
freeexp(fs, e1);
SETARG_B(getcode(fs, e2), e1->info);
e1->k = e2->k; e1->info = e2->info;
}
else {
luaK_exp2nextreg(fs, e2);
freeexp(fs, e2);
freeexp(fs, e1);
e1->info = luaK_codeABC(fs, OP_CONCAT, 0, e1->info, e2->info);
e1->k = VRELOCABLE;
}
break;
}
default: {
int o1, o2;
OpCode opc;
if (e1->k != VK) { /* not a constant operator? */
o1 = e1->info;
o2 = luaK_exp2RK(fs, e2); /* maybe other operator is constant... */
opc = codes[op];
}
else { /* invert operands */
o2 = luaK_exp2RK(fs, e1); /* constant must be 2nd operand */
o1 = luaK_exp2anyreg(fs, e2); /* other operator must be in register */
opc = invcodes[op]; /* use inverted operator */
}
freeexp(fs, e2);
freeexp(fs, e1);
if (op < OPR_NE) { /* ORDER OPR */
e1->info = luaK_codeABC(fs, opc, 0, o1, o2);
e1->k = VRELOCABLE;
}
else { /* jump */
e1->info = luaK_condjump(fs, opc, o1, 0, o2);
e1->k = VJMP;
}
}
}
}
static int luaK_code (FuncState *fs, Instruction i) {
Proto *f = fs->f;
int oldsize = f->sizecode;
/* put new instruction in code array */
luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
MAX_INT, "code size overflow");
f->code[fs->pc] = i;
if (f->sizecode != oldsize)
luaM_reallocvector(fs->L, f->lineinfo, oldsize, f->sizecode, int);
f->lineinfo[fs->pc] = fs->ls->lastline;
return fs->pc++;
}
int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
lua_assert(getOpMode(o) == iABC);
return luaK_code(fs, CREATE_ABC(o, a, b, c));
}
int luaK_codeABc (FuncState *fs, OpCode o, int a, unsigned int bc) {
lua_assert(getOpMode(o) == iABc || getOpMode(o) == iAsBc);
return luaK_code(fs, CREATE_ABc(o, a, bc));
}
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