[Tarantool-patches] [PATCH luajit 09/19] FFI: Eliminate hardcoded string hashes.
Sergey Kaplun
skaplun at tarantool.org
Wed Aug 9 18:35:58 MSK 2023
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
hardcoded string hashes) with search in the given string with the
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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