Re: [Tarantool-patches] [PATCH luajit 2/3] Reorganize lightuserdata interning code.

[sergos via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Hi! Thanks for the patch!

I would put something in description about the fact it’s pulled in just
to ease following the upstream - in particular, the following 3/3 is done
in this very moved code.

LGTM with above.

Sergos


> On 9 Sep 2021, at 10:03, Sergey Kaplun <skaplun@tarantool.org> wrote:
> 
> From: Mike Pall <mike>
> 
> This patch only performs a code movement of lightuserdata interning to
> <lj_udata.c> file and does nothing else.
> 
> Sergey Kaplun:
> * added the description for the patch
> 
> Needed for tarantool/tarantool#5629
> ---
> src/lj_api.c   | 30 ++----------------------------
> src/lj_udata.c | 27 +++++++++++++++++++++++++++
> src/lj_udata.h |  3 +++
> 3 files changed, 32 insertions(+), 28 deletions(-)
> 
> diff --git a/src/lj_api.c b/src/lj_api.c
> index c7a0b327..b6655e5a 100644
> --- a/src/lj_api.c
> +++ b/src/lj_api.c
> @@ -716,36 +716,10 @@ LUA_API void lua_pushboolean(lua_State *L, int b)
>   incr_top(L);
> }
> 
> -#if LJ_64
> -static void *lightud_intern(lua_State *L, void *p)
> -{
> -  global_State *g = G(L);
> -  uint64_t u = (uint64_t)p;
> -  uint32_t up = lightudup(u);
> -  uint32_t *segmap = mref(g->gc.lightudseg, uint32_t);
> -  MSize segnum = g->gc.lightudnum;
> -  if (segmap) {
> -    MSize seg;
> -    for (seg = 0; seg <= segnum; seg++)
> -      if (segmap[seg] == up)  /* Fast path. */
> -	return (void *)(((uint64_t)seg << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
> -    segnum++;
> -  }
> -  if (!((segnum-1) & segnum) && segnum != 1) {
> -    if (segnum >= (1 << LJ_LIGHTUD_BITS_SEG)) lj_err_msg(L, LJ_ERR_BADLU);
> -    lj_mem_reallocvec(L, segmap, segnum, segnum ? 2*segnum : 2u, uint32_t);
> -    setmref(g->gc.lightudseg, segmap);
> -  }
> -  g->gc.lightudnum = segnum;
> -  segmap[segnum] = up;
> -  return (void *)(((uint64_t)segnum << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
> -}
> -#endif
> -
> LUA_API void lua_pushlightuserdata(lua_State *L, void *p)
> {
> #if LJ_64
> -  p = lightud_intern(L, p);
> +  p = lj_lightud_intern(L, p);
> #endif
>   setrawlightudV(L->top, p);
>   incr_top(L);
> @@ -1197,7 +1171,7 @@ static TValue *cpcall(lua_State *L, lua_CFunction func, void *ud)
>   setfuncV(L, top++, fn);
>   if (LJ_FR2) setnilV(top++);
> #if LJ_64
> -  ud = lightud_intern(L, ud);
> +  ud = lj_lightud_intern(L, ud);
> #endif
>   setrawlightudV(top++, ud);
>   cframe_nres(L->cframe) = 1+0;  /* Zero results. */
> diff --git a/src/lj_udata.c b/src/lj_udata.c
> index 70c722a3..6808b1bc 100644
> --- a/src/lj_udata.c
> +++ b/src/lj_udata.c
> @@ -8,6 +8,7 @@
> 
> #include "lj_obj.h"
> #include "lj_gc.h"
> +#include "lj_err.h"
> #include "lj_udata.h"
> 
> GCudata *lj_udata_new(lua_State *L, MSize sz, GCtab *env)
> @@ -34,3 +35,29 @@ void LJ_FASTCALL lj_udata_free(global_State *g, GCudata *ud)
>   lj_mem_free(g, ud, sizeudata(ud));
> }
> 
> +#if LJ_64
> +void *lj_lightud_intern(lua_State *L, void *p)
> +{
> +  global_State *g = G(L);
> +  uint64_t u = (uint64_t)p;
> +  uint32_t up = lightudup(u);
> +  uint32_t *segmap = mref(g->gc.lightudseg, uint32_t);
> +  MSize segnum = g->gc.lightudnum;
> +  if (segmap) {
> +    MSize seg;
> +    for (seg = 0; seg <= segnum; seg++)
> +      if (segmap[seg] == up)  /* Fast path. */
> +	return (void *)(((uint64_t)seg << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
> +    segnum++;
> +  }
> +  if (!((segnum-1) & segnum) && segnum != 1) {
> +    if (segnum >= (1 << LJ_LIGHTUD_BITS_SEG)) lj_err_msg(L, LJ_ERR_BADLU);
> +    lj_mem_reallocvec(L, segmap, segnum, segnum ? 2*segnum : 2u, uint32_t);
> +    setmref(g->gc.lightudseg, segmap);
> +  }
> +  g->gc.lightudnum = segnum;
> +  segmap[segnum] = up;
> +  return (void *)(((uint64_t)segnum << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
> +}
> +#endif
> +
> diff --git a/src/lj_udata.h b/src/lj_udata.h
> index f271a42d..d97936d4 100644
> --- a/src/lj_udata.h
> +++ b/src/lj_udata.h
> @@ -10,5 +10,8 @@
> 
> LJ_FUNC GCudata *lj_udata_new(lua_State *L, MSize sz, GCtab *env);
> LJ_FUNC void LJ_FASTCALL lj_udata_free(global_State *g, GCudata *ud);
> +#if LJ_64
> +LJ_FUNC void * LJ_FASTCALL lj_lightud_intern(lua_State *L, void *p);
> +#endif
> 
> #endif
> -- 
> 2.31.0
>