/*** $Id: lparser.c,v 2.147 2014/12/27 20:31:43 roberto Exp $** Lua Parser** See Copyright Notice in lua.h*/ #define lparser_c#define LUA_CORE #include "lprefix.h" #include <string.h> #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) /* because all strings are unified by the scanner, the parser can use pointer equality for string equality */#define eqstr(a,b) ((a) == (b)) /*** nodes for block list (list of active blocks)*/typedef struct BlockCnt { struct BlockCnt *previous; /* chain */ int firstlabel; /* index of first label in this block */ int 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); /* semantic error */static l_noret semerror (LexState *ls, const char *msg) { ls->t.token = 0; /* remove "near <token>" 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 (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 (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(eqstr(gt->name, label->name)); if (gt->nactvar < label->nactvar) { TString *vname = getlocvar(fs, gt->nactvar)->varname; const char *msg = luaO_pushfstring(ls->L, "<goto %s> at line %d jumps into the scope of local '%s'", 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 (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 = n + 1; 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 (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 '%s' for <goto> 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;Lines 1–500 of 1647. 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/* ** $Id: lparser.c,v 2.147 2014/12/27 20:31:43 roberto Exp $ ** Lua Parser ** See Copyright Notice in lua.h */ #define lparser_c #define LUA_CORE #include "lprefix.h" #include <string.h> #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) /* because all strings are unified by the scanner, the parser can use pointer equality for string equality */ #define eqstr(a,b) ((a) == (b)) /* ** nodes for block list (list of active blocks) */ typedef struct BlockCnt { struct BlockCnt *previous; /* chain */ int firstlabel; /* index of first label in this block */ int 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); /* semantic error */ static l_noret semerror (LexState *ls, const char *msg) { ls->t.token = 0; /* remove "near <token>" 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 (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 (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(eqstr(gt->name, label->name)); if (gt->nactvar < label->nactvar) { TString *vname = getlocvar(fs, gt->nactvar)->varname; const char *msg = luaO_pushfstring(ls->L, "<goto %s> at line %d jumps into the scope of local '%s'", 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 (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 = n + 1; 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 (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 '%s' for <goto> 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;