/* ** $Id: lparser.c,v 2.130.1.1 2013/04/12 18:48:47 roberto Exp $ ** Lua Parser ** See Copyright Notice in lua.h */ #include #define lparser_c #define LUA_CORE #include "lua.h" #include "lcode.h" #include "ldebug.h" #include "ldo.h" #include "lfunc.h" #include "llex.h" #include "lmem.h" #include "lobject.h" #include "lopcodes.h" #include "lparser.h" #include "lstate.h" #include "lstring.h" #include "ltable.h" /* maximum number of local variables per function (must be smaller than 250, due to the bytecode format) */ #define MAXVARS 200 #define hasmultret(k) ((k) == VCALL || (k) == VVARARG) /* ** nodes for block list (list of active blocks) */ typedef struct BlockCnt { struct BlockCnt *previous; /* chain */ short firstlabel; /* index of first label in this block */ short firstgoto; /* index of first pending goto in this block */ lu_byte nactvar; /* # active locals outside the block */ lu_byte upval; /* true if some variable in the block is an upvalue */ lu_byte isloop; /* true if `block' is a loop */ } BlockCnt; /* ** prototypes for recursive non-terminal functions */ static void statement (LexState *ls); static void expr (LexState *ls, expdesc *v); static void anchor_token (LexState *ls) { /* last token from outer function must be EOS */ lua_assert(ls->fs != NULL || ls->t.token == TK_EOS); if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) { TString *ts = ls->t.seminfo.ts; luaX_newstring(ls, getstr(ts), ts->tsv.len); } } /* semantic error */ static l_noret semerror (LexState *ls, const char *msg) { ls->t.token = 0; /* remove 'near to' from final message */ luaX_syntaxerror(ls, msg); } static l_noret error_expected (LexState *ls, int token) { luaX_syntaxerror(ls, luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token))); } static l_noret errorlimit (FuncState *fs, int limit, const char *what) { lua_State *L = fs->ls->L; const char *msg; int line = fs->f->linedefined; const char *where = (line == 0) ? "main function" : luaO_pushfstring(L, "function at line %d", line); msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s", what, limit, where); luaX_syntaxerror(fs->ls, msg); } static void checklimit (FuncState *fs, int v, int l, const char *what) { if (v > l) errorlimit(fs, l, what); } static int testnext (LexState *ls, int c) { if (ls->t.token == c) { luaX_next(ls); return 1; } else return 0; } static void check (LexState *ls, int c) { if (ls->t.token != c) error_expected(ls, c); } static void checknext (LexState *ls, int c) { check(ls, c); luaX_next(ls); } #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } static void check_match (LexState *ls, int what, int who, int where) { if (!testnext(ls, what)) { if (where == ls->linenumber) error_expected(ls, what); else { luaX_syntaxerror(ls, luaO_pushfstring(ls->L, "%s expected (to close %s at line %d)", luaX_token2str(ls, what), luaX_token2str(ls, who), where)); } } } static TString *str_checkname (LexState *ls) { TString *ts; check(ls, TK_NAME); ts = ls->t.seminfo.ts; luaX_next(ls); return ts; } static void init_exp (expdesc *e, expkind k, int i) { e->f = e->t = NO_JUMP; e->k = k; e->u.info = i; } static void codestring (LexState *ls, expdesc *e, TString *s) { init_exp(e, VK, luaK_stringK(ls->fs, s)); } static void checkname (LexState *ls, expdesc *e) { codestring(ls, e, str_checkname(ls)); } static int registerlocalvar (LexState *ls, TString *varname) { FuncState *fs = ls->fs; Proto *f = fs->f; int oldsize = f->sizelocvars; luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, LocVar, SHRT_MAX, "local variables"); while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL; f->locvars[fs->nlocvars].varname = varname; luaC_objbarrier(ls->L, f, varname); return fs->nlocvars++; } static void new_localvar (LexState *ls, TString *name) { FuncState *fs = ls->fs; Dyndata *dyd = ls->dyd; int reg = registerlocalvar(ls, name); checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal, MAXVARS, "local variables"); luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1, dyd->actvar.size, Vardesc, MAX_INT, "local variables"); dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg); } static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) { new_localvar(ls, luaX_newstring(ls, name, sz)); } #define new_localvarliteral(ls,v) \ new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1) static LocVar *getlocvar (FuncState *fs, int i) { int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx; lua_assert(idx < fs->nlocvars); return &fs->f->locvars[idx]; } static void adjustlocalvars (LexState *ls, int nvars) { FuncState *fs = ls->fs; fs->nactvar = cast_byte(fs->nactvar + nvars); for (; nvars; nvars--) { getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc; } } static void removevars (FuncState *fs, int tolevel) { fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel); while (fs->nactvar > tolevel) getlocvar(fs, --fs->nactvar)->endpc = fs->pc; } static int searchupvalue (FuncState *fs, TString *name) { int i; Upvaldesc *up = fs->f->upvalues; for (i = 0; i < fs->nups; i++) { if (luaS_eqstr(up[i].name, name)) return i; } return -1; /* not found */ } static int newupvalue (FuncState *fs, TString *name, expdesc *v) { Proto *f = fs->f; int oldsize = f->sizeupvalues; checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues"); luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues, Upvaldesc, MAXUPVAL, "upvalues"); while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL; f->upvalues[fs->nups].instack = (v->k == VLOCAL); f->upvalues[fs->nups].idx = cast_byte(v->u.info); f->upvalues[fs->nups].name = name; luaC_objbarrier(fs->ls->L, f, name); return fs->nups++; } static int searchvar (FuncState *fs, TString *n) { int i; for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) { if (luaS_eqstr(n, getlocvar(fs, i)->varname)) return i; } return -1; /* not found */ } /* Mark block where variable at given level was defined (to emit close instructions later). */ static void markupval (FuncState *fs, int level) { BlockCnt *bl = fs->bl; while (bl->nactvar > level) bl = bl->previous; bl->upval = 1; } /* Find variable with given name 'n'. If it is an upvalue, add this upvalue into all intermediate functions. */ static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { if (fs == NULL) /* no more levels? */ return VVOID; /* default is global */ else { int v = searchvar(fs, n); /* look up locals at current level */ if (v >= 0) { /* found? */ init_exp(var, VLOCAL, v); /* variable is local */ if (!base) markupval(fs, v); /* local will be used as an upval */ return VLOCAL; } else { /* not found as local at current level; try upvalues */ int idx = searchupvalue(fs, n); /* try existing upvalues */ if (idx < 0) { /* not found? */ if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */ return VVOID; /* not found; is a global */ /* else was LOCAL or UPVAL */ idx = newupvalue(fs, n, var); /* will be a new upvalue */ } init_exp(var, VUPVAL, idx); return VUPVAL; } } } static void singlevar (LexState *ls, expdesc *var) { TString *varname = str_checkname(ls); FuncState *fs = ls->fs; if (singlevaraux(fs, varname, var, 1) == VVOID) { /* global name? */ expdesc key; singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ lua_assert(var->k == VLOCAL || var->k == VUPVAL); codestring(ls, &key, varname); /* key is variable name */ luaK_indexed(fs, var, &key); /* env[varname] */ } } static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { FuncState *fs = ls->fs; int extra = nvars - nexps; if (hasmultret(e->k)) { extra++; /* includes call itself */ if (extra < 0) extra = 0; luaK_setreturns(fs, e, extra); /* last exp. provides the difference */ if (extra > 1) luaK_reserveregs(fs, extra-1); } else { if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ if (extra > 0) { int reg = fs->freereg; luaK_reserveregs(fs, extra); luaK_nil(fs, reg, extra); } } } static void enterlevel (LexState *ls) { lua_State *L = ls->L; ++L->nCcalls; checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels"); } #define leavelevel(ls) ((ls)->L->nCcalls--) static void closegoto (LexState *ls, int g, Labeldesc *label) { int i; FuncState *fs = ls->fs; Labellist *gl = &ls->dyd->gt; Labeldesc *gt = &gl->arr[g]; lua_assert(luaS_eqstr(gt->name, label->name)); if (gt->nactvar < label->nactvar) { TString *vname = getlocvar(fs, gt->nactvar)->varname; const char *msg = luaO_pushfstring(ls->L, " at line %d jumps into the scope of local " LUA_QS, getstr(gt->name), gt->line, getstr(vname)); semerror(ls, msg); } luaK_patchlist(fs, gt->pc, label->pc); /* remove goto from pending list */ for (i = g; i < gl->n - 1; i++) gl->arr[i] = gl->arr[i + 1]; gl->n--; } /* ** try to close a goto with existing labels; this solves backward jumps */ static int findlabel (LexState *ls, int g) { int i; BlockCnt *bl = ls->fs->bl; Dyndata *dyd = ls->dyd; Labeldesc *gt = &dyd->gt.arr[g]; /* check labels in current block for a match */ for (i = bl->firstlabel; i < dyd->label.n; i++) { Labeldesc *lb = &dyd->label.arr[i]; if (luaS_eqstr(lb->name, gt->name)) { /* correct label? */ if (gt->nactvar > lb->nactvar && (bl->upval || dyd->label.n > bl->firstlabel)) luaK_patchclose(ls->fs, gt->pc, lb->nactvar); closegoto(ls, g, lb); /* close it */ return 1; } } return 0; /* label not found; cannot close goto */ } static int newlabelentry (LexState *ls, Labellist *l, TString *name, int line, int pc) { int n = l->n; luaM_growvector(ls->L, l->arr, n, l->size, Labeldesc, SHRT_MAX, "labels/gotos"); l->arr[n].name = name; l->arr[n].line = line; l->arr[n].nactvar = ls->fs->nactvar; l->arr[n].pc = pc; l->n++; return n; } /* ** check whether new label 'lb' matches any pending gotos in current ** block; solves forward jumps */ static void findgotos (LexState *ls, Labeldesc *lb) { Labellist *gl = &ls->dyd->gt; int i = ls->fs->bl->firstgoto; while (i < gl->n) { if (luaS_eqstr(gl->arr[i].name, lb->name)) closegoto(ls, i, lb); else i++; } } /* ** "export" pending gotos to outer level, to check them against ** outer labels; if the block being exited has upvalues, and ** the goto exits the scope of any variable (which can be the ** upvalue), close those variables being exited. */ static void movegotosout (FuncState *fs, BlockCnt *bl) { int i = bl->firstgoto; Labellist *gl = &fs->ls->dyd->gt; /* correct pending gotos to current block and try to close it with visible labels */ while (i < gl->n) { Labeldesc *gt = &gl->arr[i]; if (gt->nactvar > bl->nactvar) { if (bl->upval) luaK_patchclose(fs, gt->pc, bl->nactvar); gt->nactvar = bl->nactvar; } if (!findlabel(fs->ls, i)) i++; /* move to next one */ } } static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) { bl->isloop = isloop; bl->nactvar = fs->nactvar; bl->firstlabel = fs->ls->dyd->label.n; bl->firstgoto = fs->ls->dyd->gt.n; bl->upval = 0; bl->previous = fs->bl; fs->bl = bl; lua_assert(fs->freereg == fs->nactvar); } /* ** create a label named "break" to resolve break statements */ static void breaklabel (LexState *ls) { TString *n = luaS_new(ls->L, "break"); int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc); findgotos(ls, &ls->dyd->label.arr[l]); } /* ** generates an error for an undefined 'goto'; choose appropriate ** message when label name is a reserved word (which can only be 'break') */ static l_noret undefgoto (LexState *ls, Labeldesc *gt) { const char *msg = isreserved(gt->name) ? "<%s> at line %d not inside a loop" : "no visible label " LUA_QS " for at line %d"; msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line); semerror(ls, msg); } static void leaveblock (FuncState *fs) { BlockCnt *bl = fs->bl; LexState *ls = fs->ls; if (bl->previous && bl->upval) { /* create a 'jump to here' to close upvalues */ int j = luaK_jump(fs); luaK_patchclose(fs, j, bl->nactvar); luaK_patchtohere(fs, j); } if (bl->isloop) breaklabel(ls); /* close pending breaks */ fs->bl = bl->previous; removevars(fs, bl->nactvar); lua_assert(bl->nactvar == fs->nactvar); fs->freereg = fs->nactvar; /* free registers */ ls->dyd->label.n = bl->firstlabel; /* remove local labels */ if (bl->previous) /* inner block? */ movegotosout(fs, bl); /* update pending gotos to outer block */ else if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */ undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */ } /* ** adds a new prototype into list of prototypes */ static Proto *addprototype (LexState *ls) { Proto *clp; lua_State *L = ls->L; FuncState *fs = ls->fs; Proto *f = fs->f; /* prototype of current function */ if (fs->np >= f->sizep) { int oldsize = f->sizep; luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions"); while (oldsize < f->sizep) f->p[oldsize++] = NULL; } f->p[fs->np++] = clp = luaF_newproto(L); luaC_objbarrier(L, f, clp); return clp; } /* ** codes instruction to create new closure in parent function. ** The OP_CLOSURE instruction must use the last available register, ** so that, if it invokes the GC, the GC knows which registers ** are in use at that time. */ static void codeclosure (LexState *ls, expdesc *v) { FuncState *fs = ls->fs->prev; init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1)); luaK_exp2nextreg(fs, v); /* fix it at the last register */ } static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) { lua_State *L = ls->L; Proto *f; fs->prev = ls->fs; /* linked list of funcstates */ fs->ls = ls; ls->fs = fs; fs->pc = 0; fs->lasttarget = 0; fs->jpc = NO_JUMP; fs->freereg = 0; fs->nk = 0; fs->np = 0; fs->nups = 0; fs->nlocvars = 0; fs->nactvar = 0; fs->firstlocal = ls->dyd->actvar.n; fs->bl = NULL; f = fs->f; f->source = ls->source; f->maxstacksize = 2; /* registers 0/1 are always valid */ fs->h = luaH_new(L); /* anchor table of constants (to avoid being collected) */ sethvalue2s(L, L->top, fs->h); incr_top(L); enterblock(fs, bl, 0); } static void close_func (LexState *ls) { lua_State *L = ls->L; FuncState *fs = ls->fs; Proto *f = fs->f; luaK_ret(fs, 0, 0); /* final return */ leaveblock(fs); luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction); f->sizecode = fs->pc; luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int); f->sizelineinfo = fs->pc; luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue); f->sizek = fs->nk; luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *); f->sizep = fs->np; luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar); f->sizelocvars = fs->nlocvars; luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc); f->sizeupvalues = fs->nups; lua_assert(fs->bl == NULL); ls->fs = fs->prev; /* last token read was anchored in defunct function; must re-anchor it */ anchor_token(ls); L->top--; /* pop table of constants */ luaC_checkGC(L); } /*============================================================*/ /* GRAMMAR RULES */ /*============================================================*/ /* ** check whether current token is in the follow set of a block. ** 'until' closes syntactical blocks, but do not close scope, ** so it handled in separate. */ static int block_follow (LexState *ls, int withuntil) { switch (ls->t.token) { case TK_ELSE: case TK_ELSEIF: case TK_END: case TK_EOS: return 1; case TK_UNTIL: return withuntil; default: return 0; } } static void statlist (LexState *ls) { /* statlist -> { stat [`;'] } */ while (!block_follow(ls, 1)) { if (ls->t.token == TK_RETURN) { statement(ls); return; /* 'return' must be last statement */ } statement(ls); } } static void fieldsel (LexState *ls, expdesc *v) { /* fieldsel -> ['.' | ':'] NAME */ FuncState *fs = ls->fs; expdesc key; luaK_exp2anyregup(fs, v); luaX_next(ls); /* skip the dot or colon */ checkname(ls, &key); luaK_indexed(fs, v, &key); } static void yindex (LexState *ls, expdesc *v) { /* index -> '[' expr ']' */ luaX_next(ls); /* skip the '[' */ expr(ls, v); luaK_exp2val(ls->fs, v); checknext(ls, ']'); } /* ** {====================================================================== ** Rules for Constructors ** ======================================================================= */ struct ConsControl { expdesc v; /* last list item read */ expdesc *t; /* table descriptor */ int nh; /* total number of `record' elements */ int na; /* total number of array elements */ int tostore; /* number of array elements pending to be stored */ }; static void recfield (LexState *ls, struct ConsControl *cc) { /* recfield -> (NAME | `['exp1`]') = exp1 */ FuncState *fs = ls->fs; int reg = ls->fs->freereg; expdesc key, val; int rkkey; if (ls->t.token == TK_NAME) { checklimit(fs, cc->nh, MAX_INT, "items in a constructor"); checkname(ls, &key); } else /* ls->t.token == '[' */ yindex(ls, &key); cc->nh++; checknext(ls, '='); rkkey = luaK_exp2RK(fs, &key); expr(ls, &val); luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val)); fs->freereg = reg; /* free registers */ } static void closelistfield (FuncState *fs, struct ConsControl *cc) { if (cc->v.k == VVOID) return; /* there is no list item */ luaK_exp2nextreg(fs, &cc->v); cc->v.k = VVOID; if (cc->tostore == LFIELDS_PER_FLUSH) { luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */ cc->tostore = 0; /* no more items pending */ } } static void lastlistfield (FuncState *fs, struct ConsControl *cc) { if (cc->tostore == 0) return; if (hasmultret(cc->v.k)) { luaK_setmultret(fs, &cc->v); luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET); cc->na--; /* do not count last expression (unknown number of elements) */ } else { if (cc->v.k != VVOID) luaK_exp2nextreg(fs, &cc->v); luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); } } static void listfield (LexState *ls, struct ConsControl *cc) { /* listfield -> exp */ expr(ls, &cc->v); checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor"); cc->na++; cc->tostore++; } static void field (LexState *ls, struct ConsControl *cc) { /* field -> listfield | recfield */ switch(ls->t.token) { case TK_NAME: { /* may be 'listfield' or 'recfield' */ if (luaX_lookahead(ls) != '=') /* expression? */ listfield(ls, cc); else recfield(ls, cc); break; } case '[': { recfield(ls, cc); break; } default: { listfield(ls, cc); break; } } } static void constructor (LexState *ls, expdesc *t) { /* constructor -> '{' [ field { sep field } [sep] ] '}' sep -> ',' | ';' */ FuncState *fs = ls->fs; int line = ls->linenumber; int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0); struct ConsControl cc; cc.na = cc.nh = cc.tostore = 0; cc.t = t; init_exp(t, VRELOCABLE, pc); init_exp(&cc.v, VVOID, 0); /* no value (yet) */ luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */ checknext(ls, '{'); do { lua_assert(cc.v.k == VVOID || cc.tostore > 0); if (ls->t.token == '}') break; closelistfield(fs, &cc); field(ls, &cc); } while (testnext(ls, ',') || testnext(ls, ';')); check_match(ls, '}', '{', line); lastlistfield(fs, &cc); SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */ SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */ } /* }====================================================================== */ static void parlist (LexState *ls) { /* parlist -> [ param { `,' param } ] */ FuncState *fs = ls->fs; Proto *f = fs->f; int nparams = 0; f->is_vararg = 0; if (ls->t.token != ')') { /* is `parlist' not empty? */ do { switch (ls->t.token) { case TK_NAME: { /* param -> NAME */ new_localvar(ls, str_checkname(ls)); nparams++; break; } case TK_DOTS: { /* param -> `...' */ luaX_next(ls); f->is_vararg = 1; break; } default: luaX_syntaxerror(ls, " or " LUA_QL("...") " expected"); } } while (!f->is_vararg && testnext(ls, ',')); } adjustlocalvars(ls, nparams); f->numparams = cast_byte(fs->nactvar); luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ } static void body (LexState *ls, expdesc *e, int ismethod, int line) { /* body -> `(' parlist `)' block END */ FuncState new_fs; BlockCnt bl; new_fs.f = addprototype(ls); new_fs.f->linedefined = line; open_func(ls, &new_fs, &bl); checknext(ls, '('); if (ismethod) { new_localvarliteral(ls, "self"); /* create 'self' parameter */ adjustlocalvars(ls, 1); } parlist(ls); checknext(ls, ')'); statlist(ls); new_fs.f->lastlinedefined = ls->linenumber; check_match(ls, TK_END, TK_FUNCTION, line); codeclosure(ls, e); close_func(ls); } static int explist (LexState *ls, expdesc *v) { /* explist -> expr { `,' expr } */ int n = 1; /* at least one expression */ expr(ls, v); while (testnext(ls, ',')) { luaK_exp2nextreg(ls->fs, v); expr(ls, v); n++; } return n; } static void funcargs (LexState *ls, expdesc *f, int line) { FuncState *fs = ls->fs; expdesc args; int base, nparams; switch (ls->t.token) { case '(': { /* funcargs -> `(' [ explist ] `)' */ luaX_next(ls); if (ls->t.token == ')') /* arg list is empty? */ args.k = VVOID; else { explist(ls, &args); luaK_setmultret(fs, &args); } check_match(ls, ')', '(', line); break; } case '{': { /* funcargs -> constructor */ constructor(ls, &args); break; } case TK_STRING: { /* funcargs -> STRING */ codestring(ls, &args, ls->t.seminfo.ts); luaX_next(ls); /* must use `seminfo' before `next' */ break; } default: { luaX_syntaxerror(ls, "function arguments expected"); } } lua_assert(f->k == VNONRELOC); base = f->u.info; /* base register for call */ if (hasmultret(args.k)) nparams = LUA_MULTRET; /* open call */ else { if (args.k != VVOID) luaK_exp2nextreg(fs, &args); /* close last argument */ nparams = fs->freereg - (base+1); } init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2)); luaK_fixline(fs, line); fs->freereg = base+1; /* call remove function and arguments and leaves (unless changed) one result */ } /* ** {====================================================================== ** Expression parsing ** ======================================================================= */ static void primaryexp (LexState *ls, expdesc *v) { /* primaryexp -> NAME | '(' expr ')' */ switch (ls->t.token) { case '(': { int line = ls->linenumber; luaX_next(ls); expr(ls, v); check_match(ls, ')', '(', line); luaK_dischargevars(ls->fs, v); return; } case TK_NAME: { singlevar(ls, v); return; } default: { luaX_syntaxerror(ls, "unexpected symbol"); } } } static void suffixedexp (LexState *ls, expdesc *v) { /* suffixedexp -> primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */ FuncState *fs = ls->fs; int line = ls->linenumber; primaryexp(ls, v); for (;;) { switch (ls->t.token) { case '.': { /* fieldsel */ fieldsel(ls, v); break; } case '[': { /* `[' exp1 `]' */ expdesc key; luaK_exp2anyregup(fs, v); yindex(ls, &key); luaK_indexed(fs, v, &key); break; } case ':': { /* `:' NAME funcargs */ expdesc key; luaX_next(ls); checkname(ls, &key); luaK_self(fs, v, &key); funcargs(ls, v, line); break; } case '(': case TK_STRING: case '{': { /* funcargs */ luaK_exp2nextreg(fs, v); funcargs(ls, v, line); break; } default: return; } } } static void simpleexp (LexState *ls, expdesc *v) { /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... | constructor | FUNCTION body | suffixedexp */ switch (ls->t.token) { case TK_NUMBER: { init_exp(v, VKNUM, 0); v->u.nval = ls->t.seminfo.r; break; } case TK_STRING: { codestring(ls, v, ls->t.seminfo.ts); break; } case TK_NIL: { init_exp(v, VNIL, 0); break; } case TK_TRUE: { init_exp(v, VTRUE, 0); break; } case TK_FALSE: { init_exp(v, VFALSE, 0); break; } case TK_DOTS: { /* vararg */ FuncState *fs = ls->fs; check_condition(ls, fs->f->is_vararg, "cannot use " LUA_QL("...") " outside a vararg function"); init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0)); break; } case '{': { /* constructor */ constructor(ls, v); return; } case TK_FUNCTION: { luaX_next(ls); body(ls, v, 0, ls->linenumber); return; } default: { suffixedexp(ls, v); return; } } luaX_next(ls); } static UnOpr getunopr (int op) { switch (op) { case TK_NOT: return OPR_NOT; case '-': return OPR_MINUS; case '#': return OPR_LEN; default: return OPR_NOUNOPR; } } static BinOpr getbinopr (int op) { switch (op) { 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; } } static const struct { lu_byte left; /* left priority for each binary operator */ lu_byte right; /* right priority */ } priority[] = { /* ORDER OPR */ {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */ {10, 9}, {5, 4}, /* ^, .. (right associative) */ {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */ {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */ {2, 2}, {1, 1} /* and, or */ }; #define UNARY_PRIORITY 8 /* priority for unary operators */ /* ** subexpr -> (simpleexp | unop subexpr) { binop subexpr } ** where `binop' is any binary operator with a priority higher than `limit' */ static BinOpr subexpr (LexState *ls, expdesc *v, int limit) { BinOpr op; UnOpr uop; enterlevel(ls); uop = getunopr(ls->t.token); if (uop != OPR_NOUNOPR) { int line = ls->linenumber; luaX_next(ls); subexpr(ls, v, UNARY_PRIORITY); luaK_prefix(ls->fs, uop, v, line); } else simpleexp(ls, v); /* expand while operators have priorities higher than `limit' */ op = getbinopr(ls->t.token); while (op != OPR_NOBINOPR && priority[op].left > limit) { expdesc v2; BinOpr nextop; int line = ls->linenumber; luaX_next(ls); luaK_infix(ls->fs, op, v); /* read sub-expression with higher priority */ nextop = subexpr(ls, &v2, priority[op].right); luaK_posfix(ls->fs, op, v, &v2, line); op = nextop; } leavelevel(ls); return op; /* return first untreated operator */ } static void expr (LexState *ls, expdesc *v) { subexpr(ls, v, 0); } /* }==================================================================== */ /* ** {====================================================================== ** Rules for Statements ** ======================================================================= */ static void block (LexState *ls) { /* block -> statlist */ FuncState *fs = ls->fs; BlockCnt bl; enterblock(fs, &bl, 0); statlist(ls); leaveblock(fs); } /* ** structure to chain all variables in the left-hand side of an ** assignment */ struct LHS_assign { struct LHS_assign *prev; expdesc v; /* variable (global, local, upvalue, or indexed) */ }; /* ** check whether, in an assignment to an upvalue/local variable, the ** upvalue/local variable is begin used in a previous assignment to a ** table. If so, save original upvalue/local value in a safe place and ** use this safe copy in the previous assignment. */ static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) { FuncState *fs = ls->fs; int extra = fs->freereg; /* eventual position to save local variable */ int conflict = 0; for (; lh; lh = lh->prev) { /* check all previous assignments */ if (lh->v.k == VINDEXED) { /* assigning to a table? */ /* table is the upvalue/local being assigned now? */ if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) { conflict = 1; lh->v.u.ind.vt = VLOCAL; lh->v.u.ind.t = extra; /* previous assignment will use safe copy */ } /* index is the local being assigned? (index cannot be upvalue) */ if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) { conflict = 1; lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */ } } } if (conflict) { /* copy upvalue/local value to a temporary (in position 'extra') */ OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL; luaK_codeABC(fs, op, extra, v->u.info, 0); luaK_reserveregs(fs, 1); } } static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) { expdesc e; check_condition(ls, vkisvar(lh->v.k), "syntax error"); if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */ struct LHS_assign nv; nv.prev = lh; suffixedexp(ls, &nv.v); if (nv.v.k != VINDEXED) check_conflict(ls, lh, &nv.v); checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS, "C levels"); assignment(ls, &nv, nvars+1); } else { /* assignment -> `=' explist */ int nexps; checknext(ls, '='); nexps = explist(ls, &e); if (nexps != nvars) { adjust_assign(ls, nvars, nexps, &e); if (nexps > nvars) ls->fs->freereg -= nexps - nvars; /* remove extra values */ } else { luaK_setoneret(ls->fs, &e); /* close last expression */ luaK_storevar(ls->fs, &lh->v, &e); return; /* avoid default */ } } init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */ luaK_storevar(ls->fs, &lh->v, &e); } static int cond (LexState *ls) { /* cond -> exp */ expdesc v; expr(ls, &v); /* read condition */ if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */ luaK_goiftrue(ls->fs, &v); return v.f; } static void gotostat (LexState *ls, int pc) { int line = ls->linenumber; TString *label; int g; if (testnext(ls, TK_GOTO)) label = str_checkname(ls); else { luaX_next(ls); /* skip break */ label = luaS_new(ls->L, "break"); } g = newlabelentry(ls, &ls->dyd->gt, label, line, pc); findlabel(ls, g); /* close it if label already defined */ } /* check for repeated labels on the same block */ static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) { int i; for (i = fs->bl->firstlabel; i < ll->n; i++) { if (luaS_eqstr(label, ll->arr[i].name)) { const char *msg = luaO_pushfstring(fs->ls->L, "label " LUA_QS " already defined on line %d", getstr(label), ll->arr[i].line); semerror(fs->ls, msg); } } } /* skip no-op statements */ static void skipnoopstat (LexState *ls) { while (ls->t.token == ';' || ls->t.token == TK_DBCOLON) statement(ls); } static void labelstat (LexState *ls, TString *label, int line) { /* label -> '::' NAME '::' */ FuncState *fs = ls->fs; Labellist *ll = &ls->dyd->label; int l; /* index of new label being created */ checkrepeated(fs, ll, label); /* check for repeated labels */ checknext(ls, TK_DBCOLON); /* skip double colon */ /* create new entry for this label */ l = newlabelentry(ls, ll, label, line, fs->pc); skipnoopstat(ls); /* skip other no-op statements */ if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */ /* assume that locals are already out of scope */ ll->arr[l].nactvar = fs->bl->nactvar; } findgotos(ls, &ll->arr[l]); } static void whilestat (LexState *ls, int line) { /* whilestat -> WHILE cond DO block END */ FuncState *fs = ls->fs; int whileinit; int condexit; BlockCnt bl; luaX_next(ls); /* skip WHILE */ whileinit = luaK_getlabel(fs); condexit = cond(ls); enterblock(fs, &bl, 1); checknext(ls, TK_DO); block(ls); luaK_jumpto(fs, whileinit); check_match(ls, TK_END, TK_WHILE, line); leaveblock(fs); luaK_patchtohere(fs, condexit); /* false conditions finish the loop */ } static void repeatstat (LexState *ls, int line) { /* repeatstat -> REPEAT block UNTIL cond */ int condexit; FuncState *fs = ls->fs; int repeat_init = luaK_getlabel(fs); BlockCnt bl1, bl2; enterblock(fs, &bl1, 1); /* loop block */ enterblock(fs, &bl2, 0); /* scope block */ luaX_next(ls); /* skip REPEAT */ statlist(ls); check_match(ls, TK_UNTIL, TK_REPEAT, line); condexit = cond(ls); /* read condition (inside scope block) */ if (bl2.upval) /* upvalues? */ luaK_patchclose(fs, condexit, bl2.nactvar); leaveblock(fs); /* finish scope */ luaK_patchlist(fs, condexit, repeat_init); /* close the loop */ leaveblock(fs); /* finish loop */ } static int exp1 (LexState *ls) { expdesc e; int reg; expr(ls, &e); luaK_exp2nextreg(ls->fs, &e); lua_assert(e.k == VNONRELOC); reg = e.u.info; return reg; } static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { /* forbody -> DO block */ BlockCnt bl; FuncState *fs = ls->fs; int prep, endfor; adjustlocalvars(ls, 3); /* control variables */ checknext(ls, TK_DO); prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs); enterblock(fs, &bl, 0); /* scope for declared variables */ adjustlocalvars(ls, nvars); luaK_reserveregs(fs, nvars); block(ls); leaveblock(fs); /* end of scope for declared variables */ luaK_patchtohere(fs, prep); if (isnum) /* numeric for? */ endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP); else { /* generic for */ luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars); luaK_fixline(fs, line); endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP); } luaK_patchlist(fs, endfor, prep + 1); luaK_fixline(fs, line); } static void fornum (LexState *ls, TString *varname, int line) { /* fornum -> NAME = exp1,exp1[,exp1] forbody */ FuncState *fs = ls->fs; int base = fs->freereg; new_localvarliteral(ls, "(for index)"); new_localvarliteral(ls, "(for limit)"); new_localvarliteral(ls, "(for step)"); new_localvar(ls, varname); checknext(ls, '='); exp1(ls); /* initial value */ checknext(ls, ','); exp1(ls); /* limit */ if (testnext(ls, ',')) exp1(ls); /* optional step */ else { /* default step = 1 */ luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1)); luaK_reserveregs(fs, 1); } forbody(ls, base, line, 1, 1); } static void forlist (LexState *ls, TString *indexname) { /* forlist -> NAME {,NAME} IN explist forbody */ FuncState *fs = ls->fs; expdesc e; int nvars = 4; /* gen, state, control, plus at least one declared var */ int line; int base = fs->freereg; /* create control variables */ new_localvarliteral(ls, "(for generator)"); new_localvarliteral(ls, "(for state)"); new_localvarliteral(ls, "(for control)"); /* create declared variables */ new_localvar(ls, indexname); while (testnext(ls, ',')) { new_localvar(ls, str_checkname(ls)); nvars++; } checknext(ls, TK_IN); line = ls->linenumber; adjust_assign(ls, 3, explist(ls, &e), &e); luaK_checkstack(fs, 3); /* extra space to call generator */ forbody(ls, base, line, nvars - 3, 0); } static void forstat (LexState *ls, int line) { /* forstat -> FOR (fornum | forlist) END */ FuncState *fs = ls->fs; TString *varname; BlockCnt bl; enterblock(fs, &bl, 1); /* scope for loop and control variables */ luaX_next(ls); /* skip `for' */ varname = str_checkname(ls); /* first variable name */ switch (ls->t.token) { case '=': fornum(ls, varname, line); break; case ',': case TK_IN: forlist(ls, varname); break; default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected"); } check_match(ls, TK_END, TK_FOR, line); leaveblock(fs); /* loop scope (`break' jumps to this point) */ } static void test_then_block (LexState *ls, int *escapelist) { /* test_then_block -> [IF | ELSEIF] cond THEN block */ BlockCnt bl; FuncState *fs = ls->fs; expdesc v; int jf; /* instruction to skip 'then' code (if condition is false) */ luaX_next(ls); /* skip IF or ELSEIF */ expr(ls, &v); /* read condition */ checknext(ls, TK_THEN); if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) { luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */ enterblock(fs, &bl, 0); /* must enter block before 'goto' */ gotostat(ls, v.t); /* handle goto/break */ skipnoopstat(ls); /* skip other no-op statements */ if (block_follow(ls, 0)) { /* 'goto' is the entire block? */ leaveblock(fs); return; /* and that is it */ } else /* must skip over 'then' part if condition is false */ jf = luaK_jump(fs); } else { /* regular case (not goto/break) */ luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */ enterblock(fs, &bl, 0); jf = v.f; } statlist(ls); /* `then' part */ leaveblock(fs); if (ls->t.token == TK_ELSE || ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */ luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */ luaK_patchtohere(fs, jf); } static void ifstat (LexState *ls, int line) { /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */ FuncState *fs = ls->fs; int escapelist = NO_JUMP; /* exit list for finished parts */ test_then_block(ls, &escapelist); /* IF cond THEN block */ while (ls->t.token == TK_ELSEIF) test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */ if (testnext(ls, TK_ELSE)) block(ls); /* `else' part */ check_match(ls, TK_END, TK_IF, line); luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */ } static void localfunc (LexState *ls) { expdesc b; FuncState *fs = ls->fs; new_localvar(ls, str_checkname(ls)); /* new local variable */ adjustlocalvars(ls, 1); /* enter its scope */ body(ls, &b, 0, ls->linenumber); /* function created in next register */ /* debug information will only see the variable after this point! */ getlocvar(fs, b.u.info)->startpc = fs->pc; } static void localstat (LexState *ls) { /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */ int nvars = 0; int nexps; expdesc e; do { new_localvar(ls, str_checkname(ls)); nvars++; } while (testnext(ls, ',')); if (testnext(ls, '=')) nexps = explist(ls, &e); else { e.k = VVOID; nexps = 0; } adjust_assign(ls, nvars, nexps, &e); adjustlocalvars(ls, nvars); } static int funcname (LexState *ls, expdesc *v) { /* funcname -> NAME {fieldsel} [`:' NAME] */ int ismethod = 0; singlevar(ls, v); while (ls->t.token == '.') fieldsel(ls, v); if (ls->t.token == ':') { ismethod = 1; fieldsel(ls, v); } return ismethod; } static void funcstat (LexState *ls, int line) { /* funcstat -> FUNCTION funcname body */ int ismethod; expdesc v, b; luaX_next(ls); /* skip FUNCTION */ ismethod = funcname(ls, &v); body(ls, &b, ismethod, line); luaK_storevar(ls->fs, &v, &b); luaK_fixline(ls->fs, line); /* definition `happens' in the first line */ } static void exprstat (LexState *ls) { /* stat -> func | assignment */ FuncState *fs = ls->fs; struct LHS_assign v; suffixedexp(ls, &v.v); if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */ v.prev = NULL; assignment(ls, &v, 1); } else { /* stat -> func */ check_condition(ls, v.v.k == VCALL, "syntax error"); SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */ } } static void retstat (LexState *ls) { /* stat -> RETURN [explist] [';'] */ FuncState *fs = ls->fs; expdesc e; int first, nret; /* registers with returned values */ if (block_follow(ls, 1) || ls->t.token == ';') first = nret = 0; /* return no values */ else { nret = explist(ls, &e); /* optional return values */ if (hasmultret(e.k)) { luaK_setmultret(fs, &e); if (e.k == VCALL && nret == 1) { /* tail call? */ SET_OPCODE(getcode(fs,&e), OP_TAILCALL); lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar); } first = fs->nactvar; nret = LUA_MULTRET; /* return all values */ } else { if (nret == 1) /* only one single value? */ first = luaK_exp2anyreg(fs, &e); else { luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */ first = fs->nactvar; /* return all `active' values */ lua_assert(nret == fs->freereg - first); } } } luaK_ret(fs, first, nret); testnext(ls, ';'); /* skip optional semicolon */ } static void statement (LexState *ls) { int line = ls->linenumber; /* may be needed for error messages */ enterlevel(ls); switch (ls->t.token) { case ';': { /* stat -> ';' (empty statement) */ luaX_next(ls); /* skip ';' */ break; } case TK_IF: { /* stat -> ifstat */ ifstat(ls, line); break; } case TK_WHILE: { /* stat -> whilestat */ whilestat(ls, line); break; } case TK_DO: { /* stat -> DO block END */ luaX_next(ls); /* skip DO */ block(ls); check_match(ls, TK_END, TK_DO, line); break; } case TK_FOR: { /* stat -> forstat */ forstat(ls, line); break; } case TK_REPEAT: { /* stat -> repeatstat */ repeatstat(ls, line); break; } case TK_FUNCTION: { /* stat -> funcstat */ funcstat(ls, line); break; } case TK_LOCAL: { /* stat -> localstat */ luaX_next(ls); /* skip LOCAL */ if (testnext(ls, TK_FUNCTION)) /* local function? */ localfunc(ls); else localstat(ls); break; } case TK_DBCOLON: { /* stat -> label */ luaX_next(ls); /* skip double colon */ labelstat(ls, str_checkname(ls), line); break; } case TK_RETURN: { /* stat -> retstat */ luaX_next(ls); /* skip RETURN */ retstat(ls); break; } case TK_BREAK: /* stat -> breakstat */ case TK_GOTO: { /* stat -> 'goto' NAME */ gotostat(ls, luaK_jump(ls->fs)); break; } default: { /* stat -> func | assignment */ exprstat(ls); break; } } lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg && ls->fs->freereg >= ls->fs->nactvar); ls->fs->freereg = ls->fs->nactvar; /* free registers */ leavelevel(ls); } /* }====================================================================== */ /* ** compiles the main function, which is a regular vararg function with an ** upvalue named LUA_ENV */ static void mainfunc (LexState *ls, FuncState *fs) { BlockCnt bl; expdesc v; open_func(ls, fs, &bl); fs->f->is_vararg = 1; /* main function is always vararg */ init_exp(&v, VLOCAL, 0); /* create and... */ newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */ luaX_next(ls); /* read first token */ statlist(ls); /* parse main body */ check(ls, TK_EOS); close_func(ls); } Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, Dyndata *dyd, const char *name, int firstchar) { LexState lexstate; FuncState funcstate; Closure *cl = luaF_newLclosure(L, 1); /* create main closure */ /* anchor closure (to avoid being collected) */ setclLvalue(L, L->top, cl); incr_top(L); funcstate.f = cl->l.p = luaF_newproto(L); funcstate.f->source = luaS_new(L, name); /* create and anchor TString */ lexstate.buff = buff; lexstate.dyd = dyd; dyd->actvar.n = dyd->gt.n = dyd->label.n = 0; luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar); mainfunc(&lexstate, &funcstate); lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs); /* all scopes should be correctly finished */ lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0); return cl; /* it's on the stack too */ }