Re: A patch for _ENV support
- From: Coda Highland <chighland@xxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Thu, 25 Oct 2012 07:21:36 -0700
On Thu, Oct 25, 2012 at 12:06 AM, äé <cloudwu@xxxxxxxxx> wrote:
> It looks like that Mike dislike _ENV ;) But I really need it to
> compatible my lua 5.2 code in luajit 2.0 .
>
> So I make a patch to support it. I guess someone would need it , too.
>
> Here it is:
>
> diff --git a/src/lib_base.c b/src/lib_base.c
> index 568216e..b58a5a4 100644
> --- a/src/lib_base.c
> +++ b/src/lib_base.c
> @@ -363,6 +363,10 @@ static int load_aux(lua_State *L, int status, int envarg)
> GCtab *t = tabV(L->base+envarg-1);
> setgcref(fn->c.env, obj2gco(t));
> lj_gc_objbarrier(L, fn, t);
> + if (LJ_52) {
> + lua_pushvalue(L, envarg);
> + lua_setupvalue(L, -2, 1);
> + }
> }
> return 1;
> } else {
> diff --git a/src/lj_lex.c b/src/lj_lex.c
> index b54d2a2..59b2b84 100644
> --- a/src/lj_lex.c
> +++ b/src/lj_lex.c
> @@ -381,6 +381,7 @@ int lj_lex_setup(lua_State *L, LexState *ls)
> ls->lookahead = TK_eof; /* No look-ahead token. */
> ls->linenumber = 1;
> ls->lastline = 1;
> + ls->env = NULL;
> lj_str_resizebuf(ls->L, &ls->sb, LJ_MIN_SBUF);
> next(ls); /* Read-ahead first char. */
> if (ls->current == 0xef && ls->n >= 2 && char2int(ls->p[0]) == 0xbb &&
> diff --git a/src/lj_lex.h b/src/lj_lex.h
> index d16461a..37c15eb 100644
> --- a/src/lj_lex.h
> +++ b/src/lj_lex.h
> @@ -73,6 +73,7 @@ typedef struct LexState {
> BCInsLine *bcstack; /* Stack for bytecode instructions/line numbers. */
> MSize sizebcstack; /* Size of bytecode stack. */
> uint32_t level; /* Syntactical nesting level. */
> + GCstr *env; /* const _ENV */
> } LexState;
>
> LJ_FUNC int lj_lex_setup(lua_State *L, LexState *ls);
> diff --git a/src/lj_load.c b/src/lj_load.c
> index e30421e..5a389af 100644
> --- a/src/lj_load.c
> +++ b/src/lj_load.c
> @@ -40,6 +40,9 @@ static TValue *cpparser(lua_State *L, lua_CFunction
> dummy, void *ud)
> }
> pt = bc ? lj_bcread(ls) : lj_parse(ls);
> fn = lj_func_newL_empty(L, pt, tabref(L->env));
> + if (LJ_52) {
> + settabV(L, uvval(&gcref(fn->l.uvptr[0])->uv), tabref(L->env)); /*
> Set env table to upvalue 1 */
> + }
> /* Don't combine above/below into one statement. */
> setfuncV(L, L->top++, fn);
> return NULL;
> diff --git a/src/lj_parse.c b/src/lj_parse.c
> index 29def7b..2f435a5 100644
> --- a/src/lj_parse.c
> +++ b/src/lj_parse.c
> @@ -1112,6 +1112,12 @@ static MSize var_lookup_(FuncState *fs, GCstr
> *name, ExpDesc *e, int first)
> fscope_uvmark(fs, reg); /* Scope now has an upvalue. */
> return (MSize)(e->u.s.aux = (uint32_t)fs->varmap[reg]);
> } else {
> + if (LJ_52 && name == fs->ls->env && fs->prev == NULL) {
> + fscope_uvmark(fs,0);
> + expr_init(e, VUPVAL, 0);
> + e->u.s.aux = 0;
> + return 0;
> + }
> MSize vidx = var_lookup_(fs->prev, name, e, 0); /* Var in outer func?
> */
> if ((int32_t)vidx >= 0) { /* Yes, make it an upvalue here. */
> e->u.s.info = (uint8_t)var_lookup_uv(fs, vidx, e);
> @@ -1128,7 +1134,9 @@ static MSize var_lookup_(FuncState *fs, GCstr
> *name, ExpDesc *e, int first)
>
> /* Lookup variable name. */
> #define var_lookup(ls, e) \
> - var_lookup_((ls)->fs, lex_str(ls), (e), 1)
> + var_lookup_((ls)->fs, lex_str(ls), (e), 1); if (LJ_52 && (e)->k ==
> VGLOBAL) var_global_((ls), (e))
> +
> +static void var_global_(LexState *ls, ExpDesc *e);
>
> /* -- Goto an label handling ----------------------------------------------
> */
>
> @@ -1687,6 +1695,18 @@ static void expr_index(FuncState *fs, ExpDesc
> *t, ExpDesc *e)
> t->u.s.aux = expr_toanyreg(fs, e); /* 0..255: register */
> }
>
> +/* Convert global to _ENV index. */
> +static void var_global_(LexState *ls, ExpDesc *e)
> +{
> + FuncState *fs = ls->fs;
> + ExpDesc key;
> + expr_init(&key, VKSTR, 0);
> + key.u.sval = e->u.sval;
> + var_lookup_(fs, ls->env, e, 1);
> + expr_toanyreg(fs, e);
> + expr_index(fs, e, &key);
> +}
> +
> /* Parse index expression with named field. */
> static void expr_field(LexState *ls, ExpDesc *v)
> {
> @@ -2732,6 +2752,16 @@ GCproto *lj_parse(LexState *ls)
> fs.bcbase = NULL;
> fs.bclim = 0;
> fs.flags |= PROTO_VARARG; /* Main chunk is always a vararg func. */
> +
> + if (LJ_52) {
> + /* Create upvalue named _ENV */
> + ls->env = lj_parse_keepstr(ls, "_ENV", 4); /* Anchor _ENV
> string, 4 is sizeof _ENV */
> + var_new(ls, 0, ls->env);
> + fs.uvmap[0] = 0;
> + fs.uvtmp[0] = 0;
> + fs.nuv = 1;
> + }
> +
> fscope_begin(&fs, &bl, 0);
> bcemit_AD(&fs, BC_FUNCV, 0, 0); /* Placeholder. */
> lj_lex_next(ls); /* Read-ahead first token. */
>
>
> --
> http://blog.codingnow.com
>
Most people just go the other way around -- it's not all that hard to
implement setfenv() in terms of _ENV to make Lua 5.2 capable of
running Lua 5.1 scripts.
/s/ Adam
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