Re: [Tarantool-patches] [PATCH luajit 1/6] Abstract out on-demand loading of FFI library.

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

Hello, Sergey


thanks for the patch! LGTM


On 10/23/23 12:22, Sergey Kaplun wrote:
> From: Mike Pall <mike>
>
> (cherry-picked from commit 50d6883e6027c4c2f9a5e495fee6b7fff1bd73c9)
>
> This patch introduces the macro `ctype_loadffi(L)` to avoid code
> duplication while loading the FFI library.
>
> Sergey Kaplun:
> * added the description
>
> Part of tarantool/tarantool#9145
> ---
>   src/lib_jit.c   |  6 +-----
>   src/lj_bcread.c |  6 +-----
>   src/lj_ctype.h  | 10 ++++++++++
>   src/lj_lex.c    |  6 +-----
>   4 files changed, 13 insertions(+), 15 deletions(-)
>
> diff --git a/src/lib_jit.c b/src/lib_jit.c
> index b3c1c93c..f705f334 100644
> --- a/src/lib_jit.c
> +++ b/src/lib_jit.c
> @@ -339,11 +339,7 @@ LJLIB_CF(jit_util_tracek)
>         ir = &T->ir[ir->op1];
>       }
>   #if LJ_HASFFI
> -    if (ir->o == IR_KINT64 && !ctype_ctsG(G(L))) {
> -      ptrdiff_t oldtop = savestack(L, L->top);
> -      luaopen_ffi(L);  /* Load FFI library on-demand. */
> -      L->top = restorestack(L, oldtop);
> -    }
> +    if (ir->o == IR_KINT64) ctype_loadffi(L);
>   #endif
>       lj_ir_kvalue(L, L->top-2, ir);
>       setintV(L->top-1, (int32_t)irt_type(ir->t));
> diff --git a/src/lj_bcread.c b/src/lj_bcread.c
> index cddf6ff1..4915240f 100644
> --- a/src/lj_bcread.c
> +++ b/src/lj_bcread.c
> @@ -414,11 +414,7 @@ static int bcread_header(LexState *ls)
>     if ((flags & BCDUMP_F_FFI)) {
>   #if LJ_HASFFI
>       lua_State *L = ls->L;
> -    if (!ctype_ctsG(G(L))) {
> -      ptrdiff_t oldtop = savestack(L, L->top);
> -      luaopen_ffi(L);  /* Load FFI library on-demand. */
> -      L->top = restorestack(L, oldtop);
> -    }
> +    ctype_loadffi(L);
>   #else
>       return 0;
>   #endif
> diff --git a/src/lj_ctype.h b/src/lj_ctype.h
> index c4f3bdde..fce29409 100644
> --- a/src/lj_ctype.h
> +++ b/src/lj_ctype.h
> @@ -389,6 +389,16 @@ static LJ_AINLINE CTState *ctype_cts(lua_State *L)
>     return cts;
>   }
>   
> +/* Load FFI library on-demand. */
> +#define ctype_loadffi(L) \
> +  do { \
> +    if (!ctype_ctsG(G(L))) { \
> +      ptrdiff_t oldtop = (char *)L->top - mref(L->stack, char); \
> +      luaopen_ffi(L); \
> +      L->top = (TValue *)(mref(L->stack, char) + oldtop); \
> +    } \
> +  } while (0)
> +
>   /* Save and restore state of C type table. */
>   #define LJ_CTYPE_SAVE(cts)	CTState savects_ = *(cts)
>   #define LJ_CTYPE_RESTORE(cts) \
> diff --git a/src/lj_lex.c b/src/lj_lex.c
> index cef3c683..7c6319cc 100644
> --- a/src/lj_lex.c
> +++ b/src/lj_lex.c
> @@ -112,11 +112,7 @@ static void lex_number(LexState *ls, TValue *tv)
>       GCcdata *cd;
>       lj_assertLS(fmt == STRSCAN_I64 || fmt == STRSCAN_U64 || fmt == STRSCAN_IMAG,
>   		"unexpected number format %d", fmt);
> -    if (!ctype_ctsG(G(L))) {
> -      ptrdiff_t oldtop = savestack(L, L->top);
> -      luaopen_ffi(L);  /* Load FFI library on-demand. */
> -      L->top = restorestack(L, oldtop);
> -    }
> +    ctype_loadffi(L);
>       if (fmt == STRSCAN_IMAG) {
>         cd = lj_cdata_new_(L, CTID_COMPLEX_DOUBLE, 2*sizeof(double));
>         ((double *)cdataptr(cd))[0] = 0;