/* ** $Id: lcode.c,v 2.25.1.3 2007/12/28 15:32:23 roberto Exp $ ** Code generator for Lua ** See Copyright Notice in lua.h */ #include <stdlib.h> #define lcode_c #define LUA_CORE #include "lua.h" #include "lcode.h" #include "ldebug.h" #include "ldo.h" #include "lgc.h" #include "llex.h" #include "lmem.h" #include "lobject.h" #include "lopcodes.h" #include "lparser.h" #include "ltable.h" #define hasjumps(e) ((e)->t != (e)->f) static int isnumeral(expdesc *e) { return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP); } void luaK_nil (FuncState *fs, int from, int n) { Instruction *previous; if (fs->pc > fs->lasttarget) { /* no jumps to current position? */ if (fs->pc == 0) { /* function start? */ if (from >= fs->nactvar) return; /* positions are already clean */ } else { previous = &fs->f->code[fs->pc-1]; if (GET_OPCODE(*previous) == 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 jpc = fs->jpc; /* save list of jumps to here */ int j; fs->jpc = NO_JUMP; j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); luaK_concat(fs, &j, jpc); /* keep them on hold */ return j; } void luaK_ret (FuncState *fs, int first, int nret) { luaK_codeABC(fs, OP_RETURN, first, nret+1, 0); } static int condjump (FuncState *fs, OpCode op, int A, int B, int C) { luaK_codeABC(fs, op, A, B, C); return luaK_jump(fs); } static void fixjump (FuncState *fs, int pc, int dest) { Instruction *jmp = &fs->f->code[pc]; int offset = dest-(pc+1); lua_assert(dest != NO_JUMP); if (abs(offset) > MAXARG_sBx) luaX_syntaxerror(fs->ls, "control structure too long"); SETARG_sBx(*jmp, offset); } /* ** returns current `pc' and marks it as a jump target (to avoid wrong ** optimizations with consecutive instructions not in the same basic block). */ int luaK_getlabel (FuncState *fs) { fs->lasttarget = fs->pc; return fs->pc; } static int getjump (FuncState *fs, int pc) { int offset = GETARG_sBx(fs->f->code[pc]); if (offset == NO_JUMP) /* point to itself represents end of list */ return NO_JUMP; /* end of list */ else return (pc+1)+offset; /* turn offset into absolute position */ } static Instruction *getjumpcontrol (FuncState *fs, int pc) { Instruction *pi = &fs->f->code[pc]; if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1)))) return pi-1; else return pi; } /* ** check whether list has any jump that do not produce a value ** (or produce an inverted value) */ static int need_value (FuncState *fs, int list) { for (; list != NO_JUMP; list = getjump(fs, list)) { Instruction i = *getjumpcontrol(fs, list); if (GET_OPCODE(i) != OP_TESTSET) return 1; } return 0; /* not found */ } static int patchtestreg (FuncState *fs, int node, int reg) { Instruction *i = getjumpcontrol(fs, node); if (GET_OPCODE(*i) != OP_TESTSET) return 0; /* cannot patch other instructions */ if (reg != NO_REG && reg != GETARG_B(*i)) SETARG_A(*i, reg); else /* no register to put value or register already has the value */ *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i)); return 1; } static void removevalues (FuncState *fs, int list) { for (; list != NO_JUMP; list = getjump(fs, list)) patchtestreg(fs, list, NO_REG); } static void patchlistaux (FuncState *fs, int list, int vtarget, int reg, int dtarget) { while (list != NO_JUMP) { int next = getjump(fs, list); if (patchtestreg(fs, list, reg)) fixjump(fs, list, vtarget); else fixjump(fs, list, dtarget); /* jump to default target */ list = next; } } static void dischargejpc (FuncState *fs) { patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc); fs->jpc = NO_JUMP; } void luaK_patchlist (FuncState *fs, int list, int target) { if (target == fs->pc) luaK_patchtohere(fs, list); else { lua_assert(target < fs->pc); patchlistaux(fs, list, target, NO_REG, target); } } void luaK_patchtohere (FuncState *fs, int list) { luaK_getlabel(fs); luaK_concat(fs, &fs->jpc, list); } void luaK_concat (FuncState *fs, int *l1, int l2) { if (l2 == NO_JUMP) return; else if (*l1 == NO_JUMP) *l1 = l2; else { int list = *l1; int next; while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */ list = next; fixjump(fs, list, l2); } } void luaK_checkstack (FuncState *fs, int n) { int newstack = fs->freereg + n; if (newstack > fs->f->maxstacksize) { if (newstack >= MAXSTACK) luaX_syntaxerror(fs->ls, "function or expression too complex"); fs->f->maxstacksize = cast_byte(newstack); } } void luaK_reserveregs (FuncState *fs, int n) { luaK_checkstack(fs, n); fs->freereg += n; } static void freereg (FuncState *fs, int reg) { if (!ISK(reg) && reg >= fs->nactvar) { fs->freereg--; lua_assert(reg == fs->freereg); } } static void freeexp (FuncState *fs, expdesc *e) { if (e->k == VNONRELOC) freereg(fs, e->u.s.info); } static int addk (FuncState *fs, TValue *k, TValue *v) { lua_State *L = fs->L; TValue *idx = luaH_set(L, fs->h, k); Proto *f = fs->f; int oldsize = f->sizek; if (ttisnumber(idx)) { lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v)); return cast_int(nvalue(idx)); } else { /* constant not found; create a new entry */ setnvalue(idx, cast_num(fs->nk)); luaM_growvector(L, f->k, fs->nk, f->sizek, TValue, MAXARG_Bx, "constant table overflow"); while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]); setobj(L, &f->k[fs->nk], v); luaC_barrier(L, f, v); return fs->nk++; } } int luaK_stringK (FuncState *fs, TString *s) { TValue o; setsvalue(fs->L, &o, s); return addk(fs, &o, &o); } int luaK_numberK (FuncState *fs, lua_Number r) { TValue o; setnvalue(&o, r); return addk(fs, &o, &o); } static int boolK (FuncState *fs, int b) { TValue o; setbvalue(&o, b); return addk(fs, &o, &o); } static int nilK (FuncState *fs) { TValue k, v; setnilvalue(&v); /* cannot use nil as key; instead use table itself to represent nil */ sethvalue(fs->L, &k, fs->h); return addk(fs, &k, &v); } void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) { if (e->k == VCALL) { /* expression is an open function call? */ SETARG_C(getcode(fs, e), nresults+1); } else if (e->k == VVARARG) { SETARG_B(getcode(fs, e), nresults+1); SETARG_A(getcode(fs, e), fs->freereg); luaK_reserveregs(fs, 1); } } void luaK_setoneret (FuncState *fs, expdesc *e) { if (e->k == VCALL) { /* expression is an open function call? */ e->k = VNONRELOC; e->u.s.info = GETARG_A(getcode(fs, e)); } else if (e->k == VVARARG) { SETARG_B(getcode(fs, e), 2); e->k = VRELOCABLE; /* can relocate its simple result */ } } void luaK_dischargevars (FuncState *fs, expdesc *e) { switch (e->k) { case VLOCAL: { e->k = VNONRELOC; break; } case VUPVAL: { e->u.s.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.s.info, 0); e->k = VRELOCABLE; break; } case VGLOBAL: { e->u.s.info = luaK_codeABx(fs, OP_GETGLOBAL, 0, e->u.s.info); e->k = VRELOCABLE; break; } case VINDEXED: { freereg(fs, e->u.s.aux); freereg(fs, e->u.s.info); e->u.s.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.s.info, e->u.s.aux); e->k = VRELOCABLE; break; } case VVARARG: case VCALL: { luaK_setoneret(fs, e); break; } default: break; /* there is one value available (somewhere) */ } } static int code_label (FuncState *fs, int A, int b, int jump) { luaK_getlabel(fs); /* those instructions may be jump targets */ return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump); } static void discharge2reg (FuncState *fs, expdesc *e, int reg) { luaK_dischargevars(fs, e); switch (e->k) { case VNIL: { luaK_nil(fs, reg, 1); break; } case VFALSE: case VTRUE: { luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0); break; } case VK: { luaK_codeABx(fs, OP_LOADK, reg, e->u.s.info); break; } case VKNUM: { luaK_codeABx(fs, OP_LOADK, reg, luaK_numberK(fs, e->u.nval)); break; } case VRELOCABLE: { Instruction *pc = &getcode(fs, e); SETARG_A(*pc, reg); break; } case VNONRELOC: { if (reg != e->u.s.info) luaK_codeABC(fs, OP_MOVE, reg, e->u.s.info, 0); break; } default: { lua_assert(e->k == VVOID || e->k == VJMP); return; /* nothing to do... */ } } e->u.s.info = reg; e->k = VNONRELOC; } static void discharge2anyreg (FuncState *fs, expdesc *e) { if (e->k != VNONRELOC) { luaK_reserveregs(fs, 1); discharge2reg(fs, e, fs->freereg-1); } } static void exp2reg (FuncState *fs, expdesc *e, int reg) { discharge2reg(fs, e, reg); if (e->k == VJMP) luaK_concat(fs, &e->t, e->u.s.info); /* put this jump in `t' list */ if (hasjumps(e)) { int final; /* position after whole expression */ int p_f = NO_JUMP; /* position of an eventual LOAD false */ int p_t = NO_JUMP; /* position of an eventual LOAD true */ if (need_value(fs, e->t) || need_value(fs, e->f)) { int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs); p_f = code_label(fs, reg, 0, 1); p_t = code_label(fs, reg, 1, 0); luaK_patchtohere(fs, fj); } final = luaK_getlabel(fs); patchlistaux(fs, e->f, final, reg, p_f); patchlistaux(fs, e->t, final, reg, p_t); } e->f = e->t = NO_JUMP; e->u.s.info = reg; e->k = VNONRELOC; } void luaK_exp2nextreg (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); freeexp(fs, e); luaK_reserveregs(fs, 1); exp2reg(fs, e, fs->freereg - 1); } int luaK_exp2anyreg (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); if (e->k == VNONRELOC) { if (!hasjumps(e)) return e->u.s.info; /* exp is already in a register */ if (e->u.s.info >= fs->nactvar) { /* reg. is not a local? */ exp2reg(fs, e, e->u.s.info); /* put value on it */ return e->u.s.info; } } luaK_exp2nextreg(fs, e); /* default */ return e->u.s.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 VKNUM: case VTRUE: case VFALSE: case VNIL: { if (fs->nk <= MAXINDEXRK) { /* constant fit in RK operand? */ e->u.s.info = (e->k == VNIL) ? nilK(fs) : (e->k == VKNUM) ? luaK_numberK(fs, e->u.nval) : boolK(fs, (e->k == VTRUE)); e->k = VK; return RKASK(e->u.s.info); } else break; } case VK: { if (e->u.s.info <= MAXINDEXRK) /* constant fit in argC? */ return RKASK(e->u.s.info); else break; } default: break; } /* not a constant in the right range: put it in a register */ return luaK_exp2anyreg(fs, e); } void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) { switch (var->k) { case VLOCAL: { freeexp(fs, ex); exp2reg(fs, ex, var->u.s.info); return; } case VUPVAL: { int e = luaK_exp2anyreg(fs, ex); luaK_codeABC(fs, OP_SETUPVAL, e, var->u.s.info, 0); break; } case VGLOBAL: { int e = luaK_exp2anyreg(fs, ex); luaK_codeABx(fs, OP_SETGLOBAL, e, var->u.s.info); break; } case VINDEXED: { int e = luaK_exp2RK(fs, ex); luaK_codeABC(fs, OP_SETTABLE, var->u.s.info, var->u.s.aux, e); break; } default: { lua_assert(0); /* invalid var kind to store */ break; } } freeexp(fs, ex); } void luaK_self (FuncState *fs, expdesc *e, expdesc *key) { int func; luaK_exp2anyreg(fs, e); freeexp(fs, e); func = fs->freereg; luaK_reserveregs(fs, 2); luaK_codeABC(fs, OP_SELF, func, e->u.s.info, luaK_exp2RK(fs, key)); freeexp(fs, key); e->u.s.info = func; e->k = VNONRELOC; } static void invertjump (FuncState *fs, expdesc *e) { Instruction *pc = getjumpcontrol(fs, e->u.s.info); lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET && GET_OPCODE(*pc) != OP_TEST); SETARG_A(*pc, !(GETARG_A(*pc))); } static int jumponcond (FuncState *fs, expdesc *e, int cond) { if (e->k == VRELOCABLE) { Instruction ie = getcode(fs, e); if (GET_OPCODE(ie) == OP_NOT) { fs->pc--; /* remove previous OP_NOT */ return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond); } /* else go through */ } discharge2anyreg(fs, e); freeexp(fs, e); return condjump(fs, OP_TESTSET, NO_REG, e->u.s.info, cond); } void luaK_goiftrue (FuncState *fs, expdesc *e) { int pc; /* pc of last jump */ luaK_dischargevars(fs, e); switch (e->k) { case VK: case VKNUM: case VTRUE: { pc = NO_JUMP; /* always true; do nothing */ break; } case VFALSE: { pc = luaK_jump(fs); /* always jump */ break; } case VJMP: { invertjump(fs, e); pc = e->u.s.info; break; } default: { pc = jumponcond(fs, e, 0); break; } } luaK_concat(fs, &e->f, pc); /* insert last jump in `f' list */ luaK_patchtohere(fs, e->t); e->t = NO_JUMP; } 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_jump(fs); /* always jump */ break; } case VJMP: { pc = e->u.s.info; break; } default: { pc = jumponcond(fs, e, 1); break; } } luaK_concat(fs, &e->t, pc); /* insert last jump in `t' list */ luaK_patchtohere(fs, e->f); e->f = NO_JUMP; } static void codenot (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); switch (e->k) { case VNIL: case VFALSE: { e->k = VTRUE; break; } case VK: case VKNUM: case VTRUE: { e->k = VFALSE; break; } case VJMP: { invertjump(fs, e); break; } case VRELOCABLE: case VNONRELOC: { discharge2anyreg(fs, e); freeexp(fs, e); e->u.s.info = luaK_codeABC(fs, OP_NOT, 0, e->u.s.info, 0); e->k = VRELOCABLE; break; } default: { lua_assert(0); /* cannot happen */ break; } } /* interchange true and false lists */ { int temp = e->f; e->f = e->t; e->t = temp; } removevalues(fs, e->f); removevalues(fs, e->t); } void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) { t->u.s.aux = luaK_exp2RK(fs, k); t->k = VINDEXED; } static int constfolding (OpCode op, expdesc *e1, expdesc *e2) { lua_Number v1, v2, r; if (!isnumeral(e1) || !isnumeral(e2)) return 0; v1 = e1->u.nval; v2 = e2->u.nval; switch (op) { case OP_ADD: r = luai_numadd(v1, v2); break; case OP_SUB: r = luai_numsub(v1, v2); break; case OP_MUL: r = luai_nummul(v1, v2); break; case OP_DIV: if (v2 == 0) return 0; /* do not attempt to divide by 0 */ r = luai_numdiv(v1, v2); break; case OP_MOD: if (v2 == 0) return 0; /* do not attempt to divide by 0 */ r = luai_nummod(v1, v2); break; case OP_POW: r = luai_numpow(v1, v2); break; case OP_UNM: r = luai_numunm(v1); break; case OP_LEN: return 0; /* no constant folding for 'len' */ default: lua_assert(0); r = 0; break; } if (luai_numisnan(r)) return 0; /* do not attempt to produce NaN */ e1->u.nval = r; return 1; } static void codearith (FuncState *fs, OpCode op, expdesc *e1, expdesc *e2) { if (constfolding(op, e1, e2)) return; else { int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0; int o1 = luaK_exp2RK(fs, e1); if (o1 > o2) { freeexp(fs, e1); freeexp(fs, e2); } else { freeexp(fs, e2); freeexp(fs, e1); } e1->u.s.info = luaK_codeABC(fs, op, 0, o1, o2); e1->k = VRELOCABLE; } } static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1, expdesc *e2) { int o1 = luaK_exp2RK(fs, e1); int o2 = luaK_exp2RK(fs, e2); freeexp(fs, e2); freeexp(fs, e1); if (cond == 0 && op != OP_EQ) { int temp; /* exchange args to replace by `<' or `<=' */ temp = o1; o1 = o2; o2 = temp; /* o1 <==> o2 */ cond = 1; } e1->u.s.info = condjump(fs, op, cond, o1, o2); e1->k = VJMP; } void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e) { expdesc e2; e2.t = e2.f = NO_JUMP; e2.k = VKNUM; e2.u.nval = 0; switch (op) { case OPR_MINUS: { if (!isnumeral(e)) luaK_exp2anyreg(fs, e); /* cannot operate on non-numeric constants */ codearith(fs, OP_UNM, e, &e2); break; } case OPR_NOT: codenot(fs, e); break; case OPR_LEN: { luaK_exp2anyreg(fs, e); /* cannot operate on constants */ codearith(fs, OP_LEN, e, &e2); break; } default: lua_assert(0); } } void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) { switch (op) { case OPR_AND: { luaK_goiftrue(fs, v); break; } case OPR_OR: { luaK_goiffalse(fs, v); break; } case OPR_CONCAT: { luaK_exp2nextreg(fs, v); /* operand must be on the `stack' */ break; } case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV: case OPR_MOD: case OPR_POW: { if (!isnumeral(v)) luaK_exp2RK(fs, v); break; } default: { luaK_exp2RK(fs, v); break; } } } void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) { switch (op) { case OPR_AND: { lua_assert(e1->t == NO_JUMP); /* list must be closed */ luaK_dischargevars(fs, e2); luaK_concat(fs, &e2->f, e1->f); *e1 = *e2; break; } case OPR_OR: { lua_assert(e1->f == NO_JUMP); /* list must be closed */ luaK_dischargevars(fs, e2); luaK_concat(fs, &e2->t, e1->t); *e1 = *e2; break; } case OPR_CONCAT: { luaK_exp2val(fs, e2); if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) { lua_assert(e1->u.s.info == GETARG_B(getcode(fs, e2))-1); freeexp(fs, e1); SETARG_B(getcode(fs, e2), e1->u.s.info); e1->k = VRELOCABLE; e1->u.s.info = e2->u.s.info; } else { luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */ codearith(fs, OP_CONCAT, e1, e2); } break; } case OPR_ADD: codearith(fs, OP_ADD, e1, e2); break; case OPR_SUB: codearith(fs, OP_SUB, e1, e2); break; case OPR_MUL: codearith(fs, OP_MUL, e1, e2); break; case OPR_DIV: codearith(fs, OP_DIV, e1, e2); break; case OPR_MOD: codearith(fs, OP_MOD, e1, e2); break; case OPR_POW: codearith(fs, OP_POW, e1, e2); break; case OPR_EQ: codecomp(fs, OP_EQ, 1, e1, e2); break; case OPR_NE: codecomp(fs, OP_EQ, 0, e1, e2); break; case OPR_LT: codecomp(fs, OP_LT, 1, e1, e2); break; case OPR_LE: codecomp(fs, OP_LE, 1, e1, e2); break; case OPR_GT: codecomp(fs, OP_LT, 0, e1, e2); break; case OPR_GE: codecomp(fs, OP_LE, 0, e1, e2); break; default: lua_assert(0); } } void luaK_fixline (FuncState *fs, int line) { fs->f->lineinfo[fs->pc - 1] = line; } static int luaK_code (FuncState *fs, Instruction i, int line) { Proto *f = fs->f; dischargejpc(fs); /* `pc' will change */ /* 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; /* save corresponding line information */ luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int, MAX_INT, "code size overflow"); f->lineinfo[fs->pc] = line; return fs->pc++; } int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) { lua_assert(getOpMode(o) == iABC); lua_assert(getBMode(o) != OpArgN || b == 0); lua_assert(getCMode(o) != OpArgN || c == 0); return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline); } int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) { lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx); lua_assert(getCMode(o) == OpArgN); return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline); } void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) { int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1; int b = (tostore == LUA_MULTRET) ? 0 : tostore; lua_assert(tostore != 0); if (c <= MAXARG_C) luaK_codeABC(fs, OP_SETLIST, base, b, c); else { luaK_codeABC(fs, OP_SETLIST, base, b, 0); luaK_code(fs, cast(Instruction, c), fs->ls->lastline); } fs->freereg = base + 1; /* free registers with list values */ }