%{ /* ** $Id: lua.stx,v 1.11 1997/10/16 10:59:34 roberto Exp roberto $ ** Syntax analizer and code generator ** See Copyright Notice in lua.h */ #include #include "lauxlib.h" #include "ldo.h" #include "lfunc.h" #include "llex.h" #include "lmem.h" #include "lopcodes.h" #include "lparser.h" #include "lstring.h" #include "lua.h" #include "luadebug.h" #include "lzio.h" /* to avoid warnings generated by yacc */ int luaY_parse (void); /* size of a "normal" jump instruction: OpCode + 1 byte */ #define JMPSIZE 2 /* maximum number of local variables */ #define MAXLOCALS 32 /* maximum number of variables in a multiple assignment */ #define MAXVAR 32 /* maximum number of nested functions */ #define MAXSTATES 6 /* maximum number of upvalues */ #define MAXUPVALUES 16 /* ** Variable descriptor: if n>0, represents global variable indexed ** by (n-1); if n<0, represents local variable index (-n)-1; ** if n==0, represents an indexed variable (table and index on top of stack) ** Must be long to store negative Word values. */ typedef long vardesc; /* state needed to generate code for a given function */ typedef struct State { TProtoFunc *f; /* current function header */ int pc; /* next position to code */ TaggedString *localvar[MAXLOCALS]; /* store local variable names */ int stacksize; /* number of values on activation register */ int maxstacksize; /* maximum number of values on activation register */ int nlocalvar; /* number of active local variables */ int nupvalues; /* number of upvalues */ int nvars; /* number of entries in f->locvars */ int maxcode; /* size of f->code */ int maxvars; /* size of f->locvars (-1 if no debug information) */ int maxconsts; /* size of f->consts */ vardesc varbuffer[MAXVAR]; /* variables in an assignment list */ vardesc upvalues[MAXUPVALUES]; /* upvalues */ } State; static State *mainState, *currState; void luaY_syntaxerror (char *s, char *token) { if (token[0] == 0) token = ""; luaL_verror("%.100s;\n> last token read: \"%.50s\" at line %d in file %.50s", s, token, luaX_linenumber, mainState->f->fileName->str); } void luaY_error (char *s) { luaY_syntaxerror(s, luaX_lasttoken()); } static void check_pc (int n) { if (currState->pc+n > currState->maxcode) currState->maxcode = luaM_growvector(&currState->f->code, currState->maxcode, Byte, codeEM, MAX_INT); } static void movecode_up (int d, int s, int n) { while (n--) currState->f->code[d+n] = currState->f->code[s+n]; } static void movecode_down (int d, int s, int n) { int i; for (i=0; if->code[d+i] = currState->f->code[s+i]; } static void code_byte (Byte c) { check_pc(1); currState->f->code[currState->pc++] = c; } static void deltastack (int delta) { currState->stacksize += delta; if (currState->stacksize > currState->maxstacksize) { if (currState->stacksize > 255) luaY_error("expression too complex"); currState->maxstacksize = currState->stacksize; } } static int code_oparg_at (int pc, OpCode op, int builtin, int arg, int delta) { deltastack(delta); if (arg < builtin) { currState->f->code[pc] = op+1+arg; return 1; } else if (arg <= 255) { currState->f->code[pc] = op; currState->f->code[pc+1] = arg; return 2; } else if (arg <= MAX_WORD) { currState->f->code[pc] = op+1+builtin; currState->f->code[pc+1] = arg&0xFF; currState->f->code[pc+2] = arg>>8; return 3; } else luaY_error("construction too big - unable to compile"); return 0; /* to avoid warnings */ } static int fix_opcode (int pc, OpCode op, int builtin, int arg) { if (arg < builtin) { /* close space */ movecode_down(pc+1, pc+2, currState->pc-(pc+2)); currState->pc--; } else if (arg > 255) { /* open space */ check_pc(1); movecode_up(pc+1, pc, currState->pc-pc); currState->pc++; } return code_oparg_at(pc, op, builtin, arg, 0) - 2; } static void code_oparg (OpCode op, int builtin, int arg, int delta) { check_pc(3); /* maximum code size */ currState->pc += code_oparg_at(currState->pc, op, builtin, arg, delta); } static void code_opcode (OpCode op, int delta) { deltastack(delta); code_byte(op); } static void code_pop (OpCode op) { code_opcode(op, -1); } /* binary operations get 2 arguments and leave one, so they pop one */ #define code_binop(op) code_pop(op) static void code_neutralop (OpCode op) { code_opcode(op, 0); } /* unary operations get 1 argument and leave one, so they are neutral */ #define code_unop(op) code_neutralop(op) static void code_constant (int c) { code_oparg(PUSHCONSTANT, 8, c, 1); } static int next_constant (State *cs) { TProtoFunc *f = cs->f; if (f->nconsts >= cs->maxconsts) { cs->maxconsts = luaM_growvector(&f->consts, cs->maxconsts, TObject, constantEM, MAX_WORD); } return f->nconsts++; } static int string_constant (TaggedString *s, State *cs) { TProtoFunc *f = cs->f; int c = s->constindex; if (!(c < f->nconsts && ttype(&f->consts[c]) == LUA_T_STRING && tsvalue(&f->consts[c]) == s)) { c = next_constant(cs); ttype(&f->consts[c]) = LUA_T_STRING; tsvalue(&f->consts[c]) = s; s->constindex = c; /* hint for next time */ } return c; } static void code_string (TaggedString *s) { code_constant(string_constant(s, currState)); } #define LIM 20 static int real_constant (real r) { /* check whether 'r' has appeared within the last LIM entries */ TObject *cnt = currState->f->consts; int c = currState->f->nconsts; int lim = c < LIM ? 0 : c-LIM; while (--c >= lim) { if (ttype(&cnt[c]) == LUA_T_NUMBER && nvalue(&cnt[c]) == r) return c; } /* not found; create a luaM_new entry */ c = next_constant(currState); cnt = currState->f->consts; /* 'next_constant' may reallocate this vector */ ttype(&cnt[c]) = LUA_T_NUMBER; nvalue(&cnt[c]) = r; return c; } static void code_number (real f) { Word i; if (f >= 0 && f <= (real)MAX_WORD && (real)(i=(Word)f) == f) code_oparg(PUSHNUMBER, 3, i, 1); /* f has an (short) integer value */ else code_constant(real_constant(f)); } static void flush_record (int n) { if (n > 0) code_oparg(SETMAP, 1, n-1, -2*n); } static void flush_list (int m, int n) { if (n == 0) return; code_oparg(SETLIST, 1, m, -n); code_byte(n); } static void luaI_registerlocalvar (TaggedString *varname, int line) { if (currState->maxvars != -1) { /* debug information? */ if (currState->nvars >= currState->maxvars) currState->maxvars = luaM_growvector(&currState->f->locvars, currState->maxvars, LocVar, "", MAX_WORD); currState->f->locvars[currState->nvars].varname = varname; currState->f->locvars[currState->nvars].line = line; currState->nvars++; } } static void luaI_unregisterlocalvar (int line) { luaI_registerlocalvar(NULL, line); } static void store_localvar (TaggedString *name, int n) { if (currState->nlocalvar+n < MAXLOCALS) currState->localvar[currState->nlocalvar+n] = name; else luaY_error("too many local variables"); luaI_registerlocalvar(name, luaX_linenumber); } static void add_localvar (TaggedString *name) { store_localvar(name, 0); currState->nlocalvar++; } static void add_varbuffer (vardesc var, int n) { if (n >= MAXVAR) luaY_error("variable buffer overflow"); currState->varbuffer[n] = var; } static int aux_localname (TaggedString *n, State *st) { int i; for (i=st->nlocalvar-1; i >= 0; i--) if (n == st->localvar[i]) return i; /* local var index */ return -1; /* not found */ } static vardesc singlevar (TaggedString *n, State *st) { int i = aux_localname(n, st); if (i == -1) { /* check shadowing */ int l; for (l=1; l<=(st-mainState); l++) if (aux_localname(n, st-l) >= 0) luaY_syntaxerror("cannot access a variable in outer scope", n->str); return string_constant(n, st)+1; /* positive value */ } else return -(i+1); /* negative value */ } static int indexupvalue (TaggedString *n) { vardesc v = singlevar(n, currState-1); int i; for (i=0; inupvalues; i++) { if (currState->upvalues[i] == v) return i; } /* new one */ if (++currState->nupvalues > MAXUPVALUES) luaY_error("too many upvalues in a single function"); currState->upvalues[i] = v; /* i = currState->nupvalues - 1 */ return i; } static void pushupvalue (TaggedString *n) { int i; if (currState == mainState) luaY_error("cannot access upvalue in main"); if (aux_localname(n, currState) >= 0) luaY_syntaxerror("cannot access an upvalue in current scope", n->str); i = indexupvalue(n); code_oparg(PUSHUPVALUE, 2, i, 1); } void luaY_codedebugline (int line) { static int lastline = 0; if (lua_debug && line != lastline) { code_oparg(SETLINE, 0, line, 0); lastline = line; } } static void adjuststack (int n) { if (n > 0) code_oparg(POP, 2, n-1, -n); else if (n < 0) code_oparg(PUSHNIL, 1, (-n)-1, -n); } static long adjust_functioncall (long exp, int nresults) { if (exp <= 0) return -exp; /* exp is -list length */ else { int temp = currState->f->code[exp]; int nparams = currState->f->code[exp-1]; exp += fix_opcode(exp-2, CALLFUNC, 2, nresults); currState->f->code[exp] = nparams; if (nresults != MULT_RET) deltastack(nresults); deltastack(-(nparams+1)); return temp+nresults; } } static void adjust_mult_assign (int vars, long exps) { if (exps > 0) { /* must correct function call */ int diff = currState->f->code[exps] - vars; if (diff < 0) adjust_functioncall(exps, -diff); else { adjust_functioncall(exps, 0); adjuststack(diff); } } else adjuststack((-exps)-vars); } static void code_args (int nparams, int dots) { currState->nlocalvar += nparams; if (!dots) code_oparg(ARGS, 0, currState->nlocalvar, currState->nlocalvar); else { code_oparg(VARARGS, 0, currState->nlocalvar, currState->nlocalvar+1); add_localvar(luaS_new("arg")); } } static void lua_pushvar (vardesc number) { if (number > 0) /* global var */ code_oparg(GETGLOBAL, 8, number-1, 1); else if (number < 0) /* local var */ code_oparg(PUSHLOCAL, 8, (-number)-1, 1); else code_pop(GETTABLE); } static void storevar (vardesc number) { if (number == 0) /* indexed var */ code_opcode(SETTABLE0, -3); else if (number > 0) /* global var */ code_oparg(SETGLOBAL, 8, number-1, -1); else /* number < 0 - local var */ code_oparg(SETLOCAL, 8, (-number)-1, -1); } /* returns how many elements are left as 'garbage' on the stack */ static int lua_codestore (int i, int left) { if (currState->varbuffer[i] != 0 || /* global or local var or */ left+i == 0) { /* indexed var without values in between */ storevar(currState->varbuffer[i]); return left; } else { /* indexed var with values in between*/ code_oparg(SETTABLE, 0, left+i, -1); return left+2; /* table/index are not poped, since they are not on top */ } } static int fix_jump (int pc, OpCode op, int n) { /* jump is relative to position following jump instruction */ return fix_opcode(pc, op, 0, n-(pc+JMPSIZE)); } static void fix_upjmp (OpCode op, int pos) { int delta = currState->pc+JMPSIZE - pos; /* jump is relative */ if (delta > 255) delta++; code_oparg(op, 0, delta, 0); } static void codeIf (int thenAdd, int elseAdd) { int elseinit = elseAdd+JMPSIZE; if (currState->pc == elseinit) { /* no else part */ currState->pc -= JMPSIZE; elseinit = currState->pc; } else elseinit += fix_jump(elseAdd, JMP, currState->pc); fix_jump(thenAdd, IFFJMP, elseinit); } static void code_shortcircuit (int pc, OpCode op) { fix_jump(pc, op, currState->pc); } static void codereturn (void) { code_oparg(RETCODE, 0, currState->nlocalvar, 0); currState->stacksize = currState->nlocalvar; } static void func_onstack (TProtoFunc *f) { int i; int nupvalues = (currState+1)->nupvalues; int c = next_constant(currState); ttype(&currState->f->consts[c]) = LUA_T_PROTO; currState->f->consts[c].value.tf = (currState+1)->f; code_constant(c); for (i=0; iupvalues[i]); code_oparg(CLOSURE, 2, nupvalues, -nupvalues); } static void init_state (TaggedString *filename) { TProtoFunc *f = luaF_newproto(); currState->stacksize = 0; currState->maxstacksize = 0; currState->nlocalvar = 0; currState->nupvalues = 0; currState->f = f; f->fileName = filename; currState->pc = 0; currState->maxcode = 0; f->code = NULL; currState->maxconsts = 0; if (lua_debug) { currState->nvars = 0; currState->maxvars = 0; } else currState->maxvars = -1; /* flag no debug information */ code_byte(0); /* to be filled with stacksize */ } static void init_func (void) { if (currState-mainState >= MAXSTATES-1) luaY_error("too many nested functions"); currState++; init_state(mainState->f->fileName); luaY_codedebugline(luaX_linenumber); currState->f->lineDefined = luaX_linenumber; } static TProtoFunc *close_func (void) { TProtoFunc *f = currState->f; code_neutralop(ENDCODE); f->code[0] = currState->maxstacksize; f->code = luaM_reallocvector(f->code, currState->pc, Byte); f->consts = luaM_reallocvector(f->consts, f->nconsts, TObject); if (currState->maxvars != -1) { /* debug information? */ luaI_registerlocalvar(NULL, -1); /* flag end of vector */ f->locvars = luaM_reallocvector(f->locvars, currState->nvars, LocVar); } currState--; return f; } /* ** Parse LUA code. */ TProtoFunc *luaY_parser (ZIO *z, char *chunkname) { State state[MAXSTATES]; currState = mainState = &state[0]; luaX_setinput(z); init_state(luaS_new(chunkname)); if (luaY_parse ()) lua_error("parse error"); return close_func(); } %} %union { int vInt; real vReal; char *pChar; long vLong; TaggedString *pTStr; TProtoFunc *pFunc; } %start chunk %token WRONGTOKEN %token NIL %token IF THEN ELSE ELSEIF WHILE DO REPEAT UNTIL END %token RETURN %token LOCAL %token FUNCTION %token DOTS %token NUMBER %token NAME STRING %type SaveWord, cond, GetPC, SaveWordPop, SaveWordPush %type exprlist, exprlist1 /* if > 0, points to function return counter (which has list length); if <= 0, -list lenght */ %type functioncall, expr /* if != 0, points to function return counter */ %type varlist1, funcParams, funcvalue %type fieldlist, localnamelist, decinit %type ffieldlist, ffieldlist1, semicolonpart %type lfieldlist, lfieldlist1 %type var, funcname /* vardesc */ %type body %left AND OR %left EQ NE '>' '<' LE GE %left CONC %left '+' '-' %left '*' '/' %left UNARY NOT %right '^' %% /* beginning of rules section */ chunk : statlist ret ; statlist : /* empty */ | statlist stat sc ; sc : /* empty */ | ';' ; stat : IF cond THEN block SaveWord elsepart END { codeIf($2, $5); } | WHILE GetPC cond DO block END {{ int expsize = $3-$2; int newpos = $2+JMPSIZE; check_pc(expsize); memcpy(&currState->f->code[currState->pc], &currState->f->code[$2], expsize); movecode_down($2, $3, currState->pc-$2); newpos += fix_jump($2, JMP, currState->pc-expsize); fix_upjmp(IFTUPJMP, newpos); }} | REPEAT GetPC block UNTIL expr1 { fix_upjmp(IFFUPJMP, $2); deltastack(-1); /* pops condition */ } | varlist1 '=' exprlist1 {{ int i; int left = 0; adjust_mult_assign($1, $3); for (i=$1-1; i>=0; i--) left = lua_codestore(i, left); adjuststack(left); /* remove eventual 'garbage' left on stack */ }} | functioncall { adjust_functioncall($1, 0); } | LOCAL localnamelist decinit { currState->nlocalvar += $2; adjust_mult_assign($2, $3); } | FUNCTION funcname body { func_onstack($3); storevar($2); } ; block : {$$ = currState->nlocalvar;} chunk { adjuststack(currState->nlocalvar - $1); for (; currState->nlocalvar > $1; currState->nlocalvar--) luaI_unregisterlocalvar(luaX_linenumber); } ; funcname : var { init_func(); $$ = $1; } | varexp ':' NAME { code_string($3); $$ = 0; /* flag indexed variable */ init_func(); add_localvar(luaS_new("self")); } ; body : '(' parlist ')' chunk END { $$ = close_func(); } ; elsepart : /* empty */ | ELSE block | ELSEIF cond THEN block SaveWord elsepart { codeIf($2, $5); } ; ret : /* empty */ | RETURN exprlist sc { adjust_functioncall($2, MULT_RET); codereturn(); } ; GetPC : /* empty */ { $$ = currState->pc; } ; SaveWord : /* empty */ { $$ = currState->pc; check_pc(JMPSIZE); currState->pc += JMPSIZE; /* open space */ } ; SaveWordPop : SaveWord { $$ = $1; deltastack(-1); /* pop condition */ } ; SaveWordPush : SaveWord { $$ = $1; deltastack(1); /* push a value */ } ; cond : expr1 SaveWordPop { $$ = $2; } ; expr1 : expr { adjust_functioncall($1, 1); } ; expr : '(' expr ')' { $$ = $2; } | expr1 EQ expr1 { code_binop(EQOP); $$ = 0; } | expr1 '<' expr1 { code_binop(LTOP); $$ = 0; } | expr1 '>' expr1 { code_binop(GTOP); $$ = 0; } | expr1 NE expr1 { code_binop(NEQOP); $$ = 0; } | expr1 LE expr1 { code_binop(LEOP); $$ = 0; } | expr1 GE expr1 { code_binop(GEOP); $$ = 0; } | expr1 '+' expr1 { code_binop(ADDOP); $$ = 0; } | expr1 '-' expr1 { code_binop(SUBOP); $$ = 0; } | expr1 '*' expr1 { code_binop(MULTOP); $$ = 0; } | expr1 '/' expr1 { code_binop(DIVOP); $$ = 0; } | expr1 '^' expr1 { code_binop(POWOP); $$ = 0; } | expr1 CONC expr1 { code_binop(CONCOP); $$ = 0; } | '-' expr1 %prec UNARY { code_unop(MINUSOP); $$ = 0;} | NOT expr1 { code_unop(NOTOP); $$ = 0;} | table { $$ = 0; } | varexp { $$ = 0;} | NUMBER { code_number($1); $$ = 0; } | STRING { code_string($1); $$ = 0; } | NIL { adjuststack(-1); $$ = 0; } | functioncall { $$ = $1; } | FUNCTION { init_func(); } body { func_onstack($3); $$ = 0; } | expr1 AND SaveWordPop expr1 { code_shortcircuit($3, ONFJMP); $$ = 0; } | expr1 OR SaveWordPop expr1 { code_shortcircuit($3, ONTJMP); $$ = 0; } ; table : '{' SaveWordPush fieldlist '}' { fix_opcode($2, CREATEARRAY, 2, $3); } ; functioncall : funcvalue funcParams { code_byte(0); /* save space for opcode */ code_byte($1+$2); /* number of parameters */ $$ = currState->pc; code_byte(0); /* must be adjusted by other rules */ } ; funcvalue : varexp { $$ = 0; } | varexp ':' NAME { code_oparg(PUSHSELF, 0, string_constant($3, currState), 1); $$ = 1; } ; funcParams : '(' exprlist ')' { $$ = adjust_functioncall($2, 1); } | table { $$ = 1; } ; exprlist : /* empty */ { $$ = 0; } | exprlist1 { $$ = $1; } ; exprlist1 : expr { if ($1 != 0) $$ = $1; else $$ = -1; } | exprlist1 ',' { $$ = adjust_functioncall($1, 1); } expr { if ($4 == 0) $$ = -($3 + 1); /* -length */ else { currState->f->code[$4] = $3; /* store list length */ $$ = $4; } } ; parlist : /* empty */ { code_args(0, 0); } | DOTS { code_args(0, 1); } | localnamelist { code_args($1, 0); } | localnamelist ',' DOTS { code_args($1, 1); } ; fieldlist : lfieldlist { flush_list($1/LFIELDS_PER_FLUSH, $1%LFIELDS_PER_FLUSH); } semicolonpart { $$ = $1+$3; } | ffieldlist1 lastcomma { $$ = $1; flush_record($1%RFIELDS_PER_FLUSH); } ; semicolonpart : /* empty */ { $$ = 0; } | ';' ffieldlist { $$ = $2; flush_record($2%RFIELDS_PER_FLUSH); } ; lastcomma : /* empty */ | ',' ; ffieldlist : /* empty */ { $$ = 0; } | ffieldlist1 lastcomma { $$ = $1; } ; ffieldlist1 : ffield {$$=1;} | ffieldlist1 ',' ffield { $$=$1+1; if ($$%RFIELDS_PER_FLUSH == 0) flush_record(RFIELDS_PER_FLUSH); } ; ffield : ffieldkey '=' expr1 ; ffieldkey : '[' expr1 ']' | NAME { code_string($1); } ; lfieldlist : /* empty */ { $$ = 0; } | lfieldlist1 lastcomma { $$ = $1; } ; lfieldlist1 : expr1 {$$=1;} | lfieldlist1 ',' expr1 { $$=$1+1; if ($$%LFIELDS_PER_FLUSH == 0) flush_list($$/LFIELDS_PER_FLUSH - 1, LFIELDS_PER_FLUSH); } ; varlist1 : var { $$ = 1; add_varbuffer($1, 0); } | varlist1 ',' var { add_varbuffer($3, $1); $$ = $1+1; } ; var : NAME { $$ = singlevar($1, currState); } | varexp '[' expr1 ']' { $$ = 0; } /* indexed variable */ | varexp '.' NAME { code_string($3); $$ = 0; }/* ind. var. */ ; varexp : var { lua_pushvar($1); } | '%' NAME { pushupvalue($2); } ; localnamelist : NAME {store_localvar($1, 0); $$ = 1;} | localnamelist ',' NAME { store_localvar($3, $1); $$ = $1+1; } ; decinit : /* empty */ { $$ = 0; } | '=' exprlist1 { $$ = $2; } ; %%