From 59c88f846d1dcd901a4420651aedf27816618923 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Wed, 24 Feb 2021 11:14:44 -0300 Subject: Broadening the use of branch hints More uses of macros 'likely'/'unlikely' (renamed to 'l_likely'/'l_unlikely'), both in range (extended to the libraries) and in scope (extended to hooks, stack growth). --- lstrlib.c | 41 ++++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-) (limited to 'lstrlib.c') diff --git a/lstrlib.c b/lstrlib.c index c7242ea4..47e5b27a 100644 --- a/lstrlib.c +++ b/lstrlib.c @@ -152,8 +152,9 @@ static int str_rep (lua_State *L) { const char *s = luaL_checklstring(L, 1, &l); lua_Integer n = luaL_checkinteger(L, 2); const char *sep = luaL_optlstring(L, 3, "", &lsep); - if (n <= 0) lua_pushliteral(L, ""); - else if (l + lsep < l || l + lsep > MAXSIZE / n) /* may overflow? */ + if (n <= 0) + lua_pushliteral(L, ""); + else if (l_unlikely(l + lsep < l || l + lsep > MAXSIZE / n)) return luaL_error(L, "resulting string too large"); else { size_t totallen = (size_t)n * l + (size_t)(n - 1) * lsep; @@ -181,7 +182,7 @@ static int str_byte (lua_State *L) { size_t pose = getendpos(L, 3, pi, l); int n, i; if (posi > pose) return 0; /* empty interval; return no values */ - if (pose - posi >= (size_t)INT_MAX) /* arithmetic overflow? */ + if (l_unlikely(pose - posi >= (size_t)INT_MAX)) /* arithmetic overflow? */ return luaL_error(L, "string slice too long"); n = (int)(pose - posi) + 1; luaL_checkstack(L, n, "string slice too long"); @@ -235,7 +236,7 @@ static int str_dump (lua_State *L) { luaL_checktype(L, 1, LUA_TFUNCTION); lua_settop(L, 1); /* ensure function is on the top of the stack */ state.init = 0; - if (lua_dump(L, writer, &state, strip) != 0) + if (l_unlikely(lua_dump(L, writer, &state, strip) != 0)) return luaL_error(L, "unable to dump given function"); luaL_pushresult(&state.B); return 1; @@ -275,7 +276,8 @@ static int tonum (lua_State *L, int arg) { static void trymt (lua_State *L, const char *mtname) { lua_settop(L, 2); /* back to the original arguments */ - if (lua_type(L, 2) == LUA_TSTRING || !luaL_getmetafield(L, 2, mtname)) + if (l_unlikely(lua_type(L, 2) == LUA_TSTRING || + !luaL_getmetafield(L, 2, mtname))) luaL_error(L, "attempt to %s a '%s' with a '%s'", mtname + 2, luaL_typename(L, -2), luaL_typename(L, -1)); lua_insert(L, -3); /* put metamethod before arguments */ @@ -383,7 +385,8 @@ static const char *match (MatchState *ms, const char *s, const char *p); static int check_capture (MatchState *ms, int l) { l -= '1'; - if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED) + if (l_unlikely(l < 0 || l >= ms->level || + ms->capture[l].len == CAP_UNFINISHED)) return luaL_error(ms->L, "invalid capture index %%%d", l + 1); return l; } @@ -400,14 +403,14 @@ static int capture_to_close (MatchState *ms) { static const char *classend (MatchState *ms, const char *p) { switch (*p++) { case L_ESC: { - if (p == ms->p_end) + if (l_unlikely(p == ms->p_end)) luaL_error(ms->L, "malformed pattern (ends with '%%')"); return p+1; } case '[': { if (*p == '^') p++; do { /* look for a ']' */ - if (p == ms->p_end) + if (l_unlikely(p == ms->p_end)) luaL_error(ms->L, "malformed pattern (missing ']')"); if (*(p++) == L_ESC && p < ms->p_end) p++; /* skip escapes (e.g. '%]') */ @@ -482,7 +485,7 @@ static int singlematch (MatchState *ms, const char *s, const char *p, static const char *matchbalance (MatchState *ms, const char *s, const char *p) { - if (p >= ms->p_end - 1) + if (l_unlikely(p >= ms->p_end - 1)) luaL_error(ms->L, "malformed pattern (missing arguments to '%%b')"); if (*s != *p) return NULL; else { @@ -565,7 +568,7 @@ static const char *match_capture (MatchState *ms, const char *s, int l) { static const char *match (MatchState *ms, const char *s, const char *p) { - if (ms->matchdepth-- == 0) + if (l_unlikely(ms->matchdepth-- == 0)) luaL_error(ms->L, "pattern too complex"); init: /* using goto's to optimize tail recursion */ if (p != ms->p_end) { /* end of pattern? */ @@ -599,7 +602,7 @@ static const char *match (MatchState *ms, const char *s, const char *p) { case 'f': { /* frontier? */ const char *ep; char previous; p += 2; - if (*p != '[') + if (l_unlikely(*p != '[')) luaL_error(ms->L, "missing '[' after '%%f' in pattern"); ep = classend(ms, p); /* points to what is next */ previous = (s == ms->src_init) ? '\0' : *(s - 1); @@ -699,7 +702,7 @@ static const char *lmemfind (const char *s1, size_t l1, static size_t get_onecapture (MatchState *ms, int i, const char *s, const char *e, const char **cap) { if (i >= ms->level) { - if (i != 0) + if (l_unlikely(i != 0)) luaL_error(ms->L, "invalid capture index %%%d", i + 1); *cap = s; return e - s; @@ -707,7 +710,7 @@ static size_t get_onecapture (MatchState *ms, int i, const char *s, else { ptrdiff_t capl = ms->capture[i].len; *cap = ms->capture[i].init; - if (capl == CAP_UNFINISHED) + if (l_unlikely(capl == CAP_UNFINISHED)) luaL_error(ms->L, "unfinished capture"); else if (capl == CAP_POSITION) lua_pushinteger(ms->L, (ms->capture[i].init - ms->src_init) + 1); @@ -926,7 +929,7 @@ static int add_value (MatchState *ms, luaL_Buffer *b, const char *s, luaL_addlstring(b, s, e - s); /* keep original text */ return 0; /* no changes */ } - else if (!lua_isstring(L, -1)) + else if (l_unlikely(!lua_isstring(L, -1))) return luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1)); else { @@ -1058,7 +1061,7 @@ static int lua_number2strx (lua_State *L, char *buff, int sz, for (i = 0; i < n; i++) buff[i] = toupper(uchar(buff[i])); } - else if (fmt[SIZELENMOD] != 'a') + else if (l_unlikely(fmt[SIZELENMOD] != 'a')) return luaL_error(L, "modifiers for format '%%a'/'%%A' not implemented"); return n; } @@ -1411,7 +1414,7 @@ static int getnum (const char **fmt, int df) { */ static int getnumlimit (Header *h, const char **fmt, int df) { int sz = getnum(fmt, df); - if (sz > MAXINTSIZE || sz <= 0) + if (l_unlikely(sz > MAXINTSIZE || sz <= 0)) return luaL_error(h->L, "integral size (%d) out of limits [1,%d]", sz, MAXINTSIZE); return sz; @@ -1452,7 +1455,7 @@ static KOption getoption (Header *h, const char **fmt, int *size) { case 's': *size = getnumlimit(h, fmt, sizeof(size_t)); return Kstring; case 'c': *size = getnum(fmt, -1); - if (*size == -1) + if (l_unlikely(*size == -1)) luaL_error(h->L, "missing size for format option 'c'"); return Kchar; case 'z': return Kzstr; @@ -1491,7 +1494,7 @@ static KOption getdetails (Header *h, size_t totalsize, else { if (align > h->maxalign) /* enforce maximum alignment */ align = h->maxalign; - if ((align & (align - 1)) != 0) /* is 'align' not a power of 2? */ + if (l_unlikely((align & (align - 1)) != 0)) /* not a power of 2? */ luaL_argerror(h->L, 1, "format asks for alignment not power of 2"); *ntoalign = (align - (int)(totalsize & (align - 1))) & (align - 1); } @@ -1683,7 +1686,7 @@ static lua_Integer unpackint (lua_State *L, const char *str, else if (size > SZINT) { /* must check unread bytes */ int mask = (!issigned || (lua_Integer)res >= 0) ? 0 : MC; for (i = limit; i < size; i++) { - if ((unsigned char)str[islittle ? i : size - 1 - i] != mask) + if (l_unlikely((unsigned char)str[islittle ? i : size - 1 - i] != mask)) luaL_error(L, "%d-byte integer does not fit into Lua Integer", size); } } -- cgit v1.2.3-55-g6feb