Changed access to global table in the registry

The global table is always in the array part of the registry; we can
use this fact to make its access slightly more efficient.
This commit is contained in:
Roberto Ierusalimschy 2020-11-26 18:23:40 -03:00
parent 131e3fd814
commit 65d2294454
2 changed files with 20 additions and 14 deletions

25
lapi.c
View File

@ -629,11 +629,21 @@ static int auxgetstr (lua_State *L, const TValue *t, const char *k) {
}
/*
** Get the global table in the registry. Since all predefined
** indices in the registry were inserted right when the registry
** was created and never removed, they must always be in the array
** part of the registry.
*/
#define getGtable(L) \
(&hvalue(&G(L)->l_registry)->array[LUA_RIDX_GLOBALS - 1])
LUA_API int lua_getglobal (lua_State *L, const char *name) {
Table *reg;
const TValue *G;
lua_lock(L);
reg = hvalue(&G(L)->l_registry);
return auxgetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
G = getGtable(L);
return auxgetstr(L, G, name);
}
@ -811,10 +821,10 @@ static void auxsetstr (lua_State *L, const TValue *t, const char *k) {
LUA_API void lua_setglobal (lua_State *L, const char *name) {
Table *reg;
const TValue *G;
lua_lock(L); /* unlock done in 'auxsetstr' */
reg = hvalue(&G(L)->l_registry);
auxsetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
G = getGtable(L);
auxsetstr(L, G, name);
}
@ -1063,8 +1073,7 @@ LUA_API int lua_load (lua_State *L, lua_Reader reader, void *data,
LClosure *f = clLvalue(s2v(L->top - 1)); /* get newly created function */
if (f->nupvalues >= 1) { /* does it have an upvalue? */
/* get global table from registry */
Table *reg = hvalue(&G(L)->l_registry);
const TValue *gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
const TValue *gt = getGtable(L);
/* set global table as 1st upvalue of 'f' (may be LUA_ENV) */
setobj(L, f->upvals[0]->v, gt);
luaC_barrier(L, f->upvals[0], gt);

View File

@ -213,17 +213,14 @@ static void freestack (lua_State *L) {
** Create registry table and its predefined values
*/
static void init_registry (lua_State *L, global_State *g) {
TValue temp;
/* create registry */
Table *registry = luaH_new(L);
sethvalue(L, &g->l_registry, registry);
luaH_resize(L, registry, LUA_RIDX_LAST, 0);
/* registry[LUA_RIDX_MAINTHREAD] = L */
setthvalue(L, &temp, L); /* temp = L */
luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &temp);
/* registry[LUA_RIDX_GLOBALS] = table of globals */
sethvalue(L, &temp, luaH_new(L)); /* temp = new table (global table) */
luaH_setint(L, registry, LUA_RIDX_GLOBALS, &temp);
setthvalue(L, &registry->array[LUA_RIDX_MAINTHREAD - 1], L);
/* registry[LUA_RIDX_GLOBALS] = new table (table of globals) */
sethvalue(L, &registry->array[LUA_RIDX_GLOBALS - 1], luaH_new(L));
}