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new macros 'likely'/'unlikely' with hints for jump predictions

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(used only in errors for now)
This commit is contained in:
Roberto Ierusalimschy
2018-05-30 11:25:52 -03:00
parent 97e394ba18
commit 34aa0c5bd7
6 changed files with 78 additions and 48 deletions
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22
lvm.c
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@@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 2.354 2018/05/02 18:17:59 roberto Exp roberto $
** $Id: lvm.c,v 2.355 2018/05/22 12:02:36 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -196,7 +196,7 @@ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
if (slot == NULL) { /* 't' is not a table? */
lua_assert(!ttistable(t));
tm = luaT_gettmbyobj(L, t, TM_INDEX);
if (notm(tm))
if (unlikely(notm(tm)))
luaG_typeerror(L, t, "index"); /* no metamethod */
/* else will try the metamethod */
}
@@ -253,7 +253,7 @@ void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
}
else { /* not a table; check metamethod */
tm = luaT_gettmbyobj(L, t, TM_NEWINDEX);
if (notm(tm))
if (unlikely(notm(tm)))
luaG_typeerror(L, t, "index");
}
/* try the metamethod */
@@ -561,7 +561,7 @@ void luaV_concat (lua_State *L, int total) {
/* collect total length and number of strings */
for (n = 1; n < total && tostring(L, s2v(top - n - 1)); n++) {
size_t l = vslen(s2v(top - n - 1));
if (l >= (MAX_SIZE/sizeof(char)) - tl)
if (unlikely(l >= (MAX_SIZE/sizeof(char)) - tl))
luaG_runerror(L, "string length overflow");
tl += l;
}
@@ -605,7 +605,7 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
}
default: { /* try metamethod */
tm = luaT_gettmbyobj(L, rb, TM_LEN);
if (notm(tm)) /* no metamethod? */
if (unlikely(notm(tm))) /* no metamethod? */
luaG_typeerror(L, rb, "get length of");
break;
}
@@ -622,7 +622,7 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
*/
lua_Integer luaV_div (lua_State *L, lua_Integer m, lua_Integer n) {
if (l_castS2U(n) + 1u <= 1u) { /* special cases: -1 or 0 */
if (n == 0)
if (unlikely(n == 0))
luaG_runerror(L, "attempt to divide by zero");
return intop(-, 0, m); /* n==-1; avoid overflow with 0x80000...//-1 */
}
@@ -642,7 +642,7 @@ lua_Integer luaV_div (lua_State *L, lua_Integer m, lua_Integer n) {
*/
lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) {
if (l_castS2U(n) + 1u <= 1u) { /* special cases: -1 or 0 */
if (n == 0)
if (unlikely(n == 0))
luaG_runerror(L, "attempt to perform 'n%%0'");
return 0; /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
}
@@ -1665,7 +1665,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
TValue *plimit = s2v(ra + 1);
lua_Integer ilimit, initv;
int stopnow;
if (!forlimit(plimit, &ilimit, 1, &stopnow)) {
if (unlikely(!forlimit(plimit, &ilimit, 1, &stopnow))) {
savestate(L, ci); /* for the error message */
luaG_runerror(L, "'for' limit must be a number");
}
@@ -1717,13 +1717,13 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
else { /* try making all values floats */
lua_Number ninit; lua_Number nlimit; lua_Number nstep;
savestate(L, ci); /* in case of errors */
if (!tonumber(plimit, &nlimit))
if (unlikely(!tonumber(plimit, &nlimit)))
luaG_runerror(L, "'for' limit must be a number");
setfltvalue(plimit, nlimit);
if (!tonumber(pstep, &nstep))
if (unlikely(!tonumber(pstep, &nstep)))
luaG_runerror(L, "'for' step must be a number");
setfltvalue(pstep, nstep);
if (!tonumber(init, &ninit))
if (unlikely(!tonumber(init, &ninit)))
luaG_runerror(L, "'for' initial value must be a number");
setfltvalue(init, luai_numsub(L, ninit, nstep));
}