[Tarantool-patches] [PATCH luajit 09/19] FFI: Eliminate hardcoded string hashes.
Maxim Kokryashkin
m.kokryashkin at tarantool.org
Tue Aug 15 16:07:41 MSK 2023
Hi, Sergey!
Thanks for the patch!
LGTM, except for a few comments below.
On Wed, Aug 09, 2023 at 06:35:58PM +0300, Sergey Kaplun via Tarantool-patches wrote:
> From: Mike Pall <mike>
>
> (cherry-picked from commit 70f4b15ee45a6137fe6b48b941faea79d72f7159)
>
> This patch refactors FFI parsing of supported C attributes and pragmas,
> `ffi.abi()` parameter check. It replaces usage of comparison (with
Typo: s/usage/the usage/
> hardcoded string hashes) with search in the given string with the
Typo: s/with search/with a search/
> format: "\XXXattribute1\XXXattribute2", where `\XXX` is the length of
> "attribute" name.
>
> Sergey Kaplun:
> * added the description for the commit
>
> Part of tarantool/tarantool#8825
> ---
> src/lib_ffi.c | 35 ++++++++++------------
> src/lj_cparse.c | 77 +++++++++++++++++++++++++++++++------------------
> src/lj_cparse.h | 2 ++
> 3 files changed, 67 insertions(+), 47 deletions(-)
>
> diff --git a/src/lib_ffi.c b/src/lib_ffi.c
> index d1fe1a14..62af54c1 100644
> --- a/src/lib_ffi.c
> +++ b/src/lib_ffi.c
> @@ -720,50 +720,47 @@ LJLIB_CF(ffi_fill) LJLIB_REC(.)
> return 0;
> }
>
> -#define H_(le, be) LJ_ENDIAN_SELECT(0x##le, 0x##be)
> -
> /* Test ABI string. */
> LJLIB_CF(ffi_abi) LJLIB_REC(.)
> {
> GCstr *s = lj_lib_checkstr(L, 1);
> - int b = 0;
> - switch (s->hash) {
> + int b = lj_cparse_case(s,
> #if LJ_64
> - case H_(849858eb,ad35fd06): b = 1; break; /* 64bit */
> + "\00564bit"
> #else
> - case H_(662d3c79,d0e22477): b = 1; break; /* 32bit */
> + "\00532bit"
> #endif
> #if LJ_ARCH_HASFPU
> - case H_(e33ee463,e33ee463): b = 1; break; /* fpu */
> + "\003fpu"
> #endif
> #if LJ_ABI_SOFTFP
> - case H_(61211a23,c2e8c81c): b = 1; break; /* softfp */
> + "\006softfp"
> #else
> - case H_(539417a8,8ce0812f): b = 1; break; /* hardfp */
> + "\006hardfp"
> #endif
> #if LJ_ABI_EABI
> - case H_(2182df8f,f2ed1152): b = 1; break; /* eabi */
> + "\004eabi"
> #endif
> #if LJ_ABI_WIN
> - case H_(4ab624a8,4ab624a8): b = 1; break; /* win */
> + "\003win"
> #endif
> #if LJ_TARGET_UWP
> - case H_(a40f0bcb,a40f0bcb): b = 1; break; /* uwp */
> + "\003uwp"
> +#endif
> +#if LJ_LE
> + "\002le"
> +#else
> + "\002be"
> #endif
> - case H_(3af93066,1f001464): b = 1; break; /* le/be */
> #if LJ_GC64
> - case H_(9e89d2c9,13c83c92): b = 1; break; /* gc64 */
> + "\004gc64"
> #endif
> - default:
> - break;
> - }
> + ) >= 0;
> setboolV(L->top-1, b);
> setboolV(&G(L)->tmptv2, b); /* Remember for trace recorder. */
> return 1;
> }
>
> -#undef H_
> -
> LJLIB_PUSH(top-8) LJLIB_SET(!) /* Store reference to miscmap table. */
>
> LJLIB_CF(ffi_metatype)
> diff --git a/src/lj_cparse.c b/src/lj_cparse.c
> index fb440567..07c643d4 100644
> --- a/src/lj_cparse.c
> +++ b/src/lj_cparse.c
> @@ -28,6 +28,24 @@
> ** If in doubt, please check the input against your favorite C compiler.
> */
>
> +/* -- Miscellaneous ------------------------------------------------------- */
> +
> +/* Match string against a C literal. */
> +#define cp_str_is(str, k) \
> + ((str)->len == sizeof(k)-1 && !memcmp(strdata(str), k, sizeof(k)-1))
> +
> +/* Check string against a linear list of matches. */
> +int lj_cparse_case(GCstr *str, const char *match)
> +{
> + MSize len;
> + int n;
> + for (n = 0; (len = (MSize)*match++); n++, match += len) {
> + if (str->len == len && !memcmp(match, strdata(str), len))
> + return n;
> + }
> + return -1;
> +}
> +
> /* -- C lexer ------------------------------------------------------------- */
>
> /* C lexer token names. */
> @@ -930,8 +948,6 @@ static CTypeID cp_decl_intern(CPState *cp, CPDecl *decl)
>
> /* -- C declaration parser ------------------------------------------------ */
>
> -#define H_(le, be) LJ_ENDIAN_SELECT(0x##le, 0x##be)
> -
> /* Reset declaration state to declaration specifier. */
> static void cp_decl_reset(CPDecl *decl)
> {
> @@ -1071,44 +1087,57 @@ static void cp_decl_gccattribute(CPState *cp, CPDecl *decl)
> attrstr = lj_str_new(cp->L, c+2, attrstr->len-4);
> #endif
> cp_next(cp);
> - switch (attrstr->hash) {
> - case H_(64a9208e,8ce14319): case H_(8e6331b2,95a282af): /* aligned */
> + switch (lj_cparse_case(attrstr,
> + "\007aligned" "\013__aligned__"
> + "\006packed" "\012__packed__"
> + "\004mode" "\010__mode__"
> + "\013vector_size" "\017__vector_size__"
> +#if LJ_TARGET_X86
> + "\007regparm" "\013__regparm__"
> + "\005cdecl" "\011__cdecl__"
> + "\010thiscall" "\014__thiscall__"
> + "\010fastcall" "\014__fastcall__"
> + "\007stdcall" "\013__stdcall__"
> + "\012sseregparm" "\016__sseregparm__"
> +#endif
> + )) {
> + case 0: case 1: /* aligned */
> cp_decl_align(cp, decl);
> break;
> - case H_(42eb47de,f0ede26c): case H_(29f48a09,cf383e0c): /* packed */
> + case 2: case 3: /* packed */
> decl->attr |= CTFP_PACKED;
> break;
> - case H_(0a84eef6,8dfab04c): case H_(995cf92c,d5696591): /* mode */
> + case 4: case 5: /* mode */
> cp_decl_mode(cp, decl);
> break;
> - case H_(0ab31997,2d5213fa): case H_(bf875611,200e9990): /* vector_size */
> + case 6: case 7: /* vector_size */
> {
> CTSize vsize = cp_decl_sizeattr(cp);
> if (vsize) CTF_INSERT(decl->attr, VSIZEP, lj_fls(vsize));
> }
> break;
> #if LJ_TARGET_X86
> - case H_(5ad22db8,c689b848): case H_(439150fa,65ea78cb): /* regparm */
> + case 8: case 9: /* regparm */
> CTF_INSERT(decl->fattr, REGPARM, cp_decl_sizeattr(cp));
> decl->fattr |= CTFP_CCONV;
> break;
> - case H_(18fc0b98,7ff4c074): case H_(4e62abed,0a747424): /* cdecl */
> + case 10: case 11: /* cdecl */
> CTF_INSERT(decl->fattr, CCONV, CTCC_CDECL);
> decl->fattr |= CTFP_CCONV;
> break;
> - case H_(72b2e41b,494c5a44): case H_(f2356d59,f25fc9bd): /* thiscall */
> + case 12: case 13: /* thiscall */
> CTF_INSERT(decl->fattr, CCONV, CTCC_THISCALL);
> decl->fattr |= CTFP_CCONV;
> break;
> - case H_(0d0ffc42,ab746f88): case H_(21c54ba1,7f0ca7e3): /* fastcall */
> + case 14: case 15: /* fastcall */
> CTF_INSERT(decl->fattr, CCONV, CTCC_FASTCALL);
> decl->fattr |= CTFP_CCONV;
> break;
> - case H_(ef76b040,9412e06a): case H_(de56697b,c750e6e1): /* stdcall */
> + case 16: case 17: /* stdcall */
> CTF_INSERT(decl->fattr, CCONV, CTCC_STDCALL);
> decl->fattr |= CTFP_CCONV;
> break;
> - case H_(ea78b622,f234bd8e): case H_(252ffb06,8d50f34b): /* sseregparm */
> + case 18: case 19: /* sseregparm */
> decl->fattr |= CTF_SSEREGPARM;
> decl->fattr |= CTFP_CCONV;
> break;
> @@ -1140,16 +1169,13 @@ static void cp_decl_msvcattribute(CPState *cp, CPDecl *decl)
> while (cp->tok == CTOK_IDENT) {
> GCstr *attrstr = cp->str;
> cp_next(cp);
> - switch (attrstr->hash) {
> - case H_(bc2395fa,98f267f8): /* align */
> + if (cp_str_is(attrstr, "align")) {
> cp_decl_align(cp, decl);
> - break;
> - default: /* Ignore all other attributes. */
> + } else { /* Ignore all other attributes. */
> if (cp_opt(cp, '(')) {
> while (cp->tok != ')' && cp->tok != CTOK_EOF) cp_next(cp);
> cp_check(cp, ')');
> }
> - break;
> }
> }
> cp_check(cp, ')');
> @@ -1729,17 +1755,16 @@ static CTypeID cp_decl_abstract(CPState *cp)
> static void cp_pragma(CPState *cp, BCLine pragmaline)
> {
> cp_next(cp);
> - if (cp->tok == CTOK_IDENT &&
> - cp->str->hash == H_(e79b999f,42ca3e85)) { /* pack */
> + if (cp->tok == CTOK_IDENT && cp_str_is(cp->str, "pack")) {
> cp_next(cp);
> cp_check(cp, '(');
> if (cp->tok == CTOK_IDENT) {
> - if (cp->str->hash == H_(738e923c,a1b65954)) { /* push */
> + if (cp_str_is(cp->str, "push")) {
> if (cp->curpack < CPARSE_MAX_PACKSTACK) {
> cp->packstack[cp->curpack+1] = cp->packstack[cp->curpack];
> cp->curpack++;
> }
> - } else if (cp->str->hash == H_(6c71cf27,6c71cf27)) { /* pop */
> + } else if (cp_str_is(cp->str, "pop")) {
> if (cp->curpack > 0) cp->curpack--;
> } else {
> cp_errmsg(cp, cp->tok, LJ_ERR_XSYMBOL);
> @@ -1788,13 +1813,11 @@ static void cp_decl_multi(CPState *cp)
> if (tok == CTOK_INTEGER) {
> cp_line(cp, hashline);
> continue;
> - } else if (tok == CTOK_IDENT &&
> - cp->str->hash == H_(187aab88,fcb60b42)) { /* line */
> + } else if (tok == CTOK_IDENT && cp_str_is(cp->str, "line")) {
> if (cp_next(cp) != CTOK_INTEGER) cp_err_token(cp, tok);
> cp_line(cp, hashline);
> continue;
> - } else if (tok == CTOK_IDENT &&
> - cp->str->hash == H_(f5e6b4f8,1d509107)) { /* pragma */
> + } else if (tok == CTOK_IDENT && cp_str_is(cp->str, "pragma")) {
> cp_pragma(cp, hashline);
> continue;
> } else {
> @@ -1865,8 +1888,6 @@ static void cp_decl_single(CPState *cp)
> if (cp->tok != CTOK_EOF) cp_err_token(cp, CTOK_EOF);
> }
>
> -#undef H_
> -
> /* ------------------------------------------------------------------------ */
>
> /* Protected callback for C parser. */
> diff --git a/src/lj_cparse.h b/src/lj_cparse.h
> index bad1060b..e40b4047 100644
> --- a/src/lj_cparse.h
> +++ b/src/lj_cparse.h
> @@ -60,6 +60,8 @@ typedef struct CPState {
>
> LJ_FUNC int lj_cparse(CPState *cp);
>
> +LJ_FUNC int lj_cparse_case(GCstr *str, const char *match);
> +
> #endif
>
> #endif
> --
> 2.41.0
>
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