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parser keeps list of active local variables in a single dynamic array,

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therefore saving C stack space
This commit is contained in:
Roberto Ierusalimschy
2009-10-11 17:02:19 -03:00
parent a5382b763c
commit 916587508c
7 changed files with 76 additions and 47 deletions
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80
lparser.c
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@@ -1,5 +1,5 @@
/*
** $Id: lparser.c,v 2.67 2009/09/28 16:32:50 roberto Exp roberto $
** $Id: lparser.c,v 2.68 2009/09/30 15:38:37 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -27,9 +27,14 @@
/* 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)
#define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i].idx])
#define luaY_checklimit(fs,v,l,m) if ((v)>(l)) errorlimit(fs,l,m)
@@ -157,15 +162,26 @@ static int registerlocalvar (LexState *ls, TString *varname) {
}
#define new_localvarliteral(ls,v,n) \
new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
#define new_localvarliteral(ls,v) \
new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1))
static void new_localvar (LexState *ls, TString *name, int n) {
static void new_localvar (LexState *ls, TString *name) {
FuncState *fs = ls->fs;
Varlist *vl = ls->varl;
int reg = registerlocalvar(ls, name);
luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables");
fs->actvar[fs->nactvar+n].idx = cast(unsigned short, reg);
luaY_checklimit(fs, vl->nactvar + 1 - fs->firstlocal,
MAXVARS, "local variables");
luaM_growvector(ls->L, vl->actvar, vl->nactvar + 1,
vl->actvarsize, vardesc, MAX_INT, "local variables");
vl->actvar[vl->nactvar++].idx = cast(unsigned short, reg);
}
static LocVar *getlocvar (FuncState *fs, int i) {
int idx = fs->ls->varl->actvar[fs->firstlocal + i].idx;
lua_assert(idx < fs->nlocvars);
return &fs->f->locvars[idx];
}
@@ -173,14 +189,15 @@ 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;
getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc;
}
}
static void removevars (FuncState *fs, int tolevel) {
fs->ls->varl->nactvar -= (fs->nactvar - tolevel);
while (fs->nactvar > tolevel)
getlocvar(fs, --fs->nactvar).endpc = fs->pc;
getlocvar(fs, --fs->nactvar)->endpc = fs->pc;
}
@@ -212,7 +229,7 @@ static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
static int searchvar (FuncState *fs, TString *n) {
int i;
for (i=fs->nactvar-1; i >= 0; i--) {
if (n == getlocvar(fs, i).varname)
if (n == getlocvar(fs, i)->varname)
return i;
}
return -1; /* not found */
@@ -350,6 +367,7 @@ static void open_func (LexState *ls, FuncState *fs) {
fs->nups = 0;
fs->nlocvars = 0;
fs->nactvar = 0;
fs->firstlocal = ls->varl->nactvar;
fs->envreg = NO_REG;
fs->bl = NULL;
fs->h = luaH_new(L);
@@ -392,13 +410,15 @@ static void close_func (LexState *ls) {
}
Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, Varlist *varl,
const char *name) {
struct LexState lexstate;
struct FuncState funcstate;
TString *tname = luaS_new(L, name);
setsvalue2s(L, L->top, tname); /* protect name */
incr_top(L);
lexstate.buff = buff;
lexstate.varl = varl;
luaX_setinput(L, &lexstate, z, tname);
open_func(&lexstate, &funcstate);
funcstate.f->is_vararg = 1; /* main func. is always vararg */
@@ -565,7 +585,8 @@ static void parlist (LexState *ls) {
do {
switch (ls->t.token) {
case TK_NAME: { /* param -> NAME */
new_localvar(ls, str_checkname(ls), nparams++);
new_localvar(ls, str_checkname(ls));
nparams++;
break;
}
case TK_DOTS: { /* param -> `...' */
@@ -590,7 +611,7 @@ static void body (LexState *ls, expdesc *e, int needself, int line) {
new_fs.f->linedefined = line;
checknext(ls, '(');
if (needself) {
new_localvarliteral(ls, "self", 0);
new_localvarliteral(ls, "self");
adjustlocalvars(ls, 1);
}
parlist(ls);
@@ -1083,10 +1104,10 @@ 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)", 0);
new_localvarliteral(ls, "(for limit)", 1);
new_localvarliteral(ls, "(for step)", 2);
new_localvar(ls, varname, 3);
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, ',');
@@ -1105,17 +1126,19 @@ static void forlist (LexState *ls, TString *indexname) {
/* forlist -> NAME {,NAME} IN explist1 forbody */
FuncState *fs = ls->fs;
expdesc e;
int nvars = 0;
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)", nvars++);
new_localvarliteral(ls, "(for state)", nvars++);
new_localvarliteral(ls, "(for control)", nvars++);
new_localvarliteral(ls, "(for generator)");
new_localvarliteral(ls, "(for state)");
new_localvarliteral(ls, "(for control)");
/* create declared variables */
new_localvar(ls, indexname, nvars++);
while (testnext(ls, ','))
new_localvar(ls, str_checkname(ls), nvars++);
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, explist1(ls, &e), &e);
@@ -1180,14 +1203,14 @@ static void ifstat (LexState *ls, int line) {
static void localfunc (LexState *ls) {
expdesc v, b;
FuncState *fs = ls->fs;
new_localvar(ls, str_checkname(ls), 0);
new_localvar(ls, str_checkname(ls));
init_exp(&v, VLOCAL, fs->freereg);
luaK_reserveregs(fs, 1);
adjustlocalvars(ls, 1);
body(ls, &b, 0, ls->linenumber);
luaK_storevar(fs, &v, &b);
/* debug information will only see the variable after this point! */
getlocvar(fs, fs->nactvar - 1).startpc = fs->pc;
getlocvar(fs, fs->nactvar - 1)->startpc = fs->pc;
}
@@ -1197,7 +1220,8 @@ static void localstat (LexState *ls) {
int nexps;
expdesc e;
do {
new_localvar(ls, str_checkname(ls), nvars++);
new_localvar(ls, str_checkname(ls));
nvars++;
} while (testnext(ls, ','));
if (testnext(ls, '='))
nexps = explist1(ls, &e);
@@ -1243,7 +1267,7 @@ static void instat (LexState *ls, int line) {
BlockCnt bl;
luaX_next(ls); /* skip IN */
enterblock(fs, &bl, 0); /* scope for environment variable */
new_localvarliteral(ls, "(environment)", 0);
new_localvarliteral(ls, "(environment)");
fs->envreg = exp1(ls); /* new environment */
adjustlocalvars(ls, 1);
checknext(ls, TK_DO);