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No more field 'lua_State.stacksize'

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The stack size is derived from 'stack_last', when needed. Moreover,
the handling of stack sizes is more consistent, always excluding the
extra space except when allocating/deallocating the array.
This commit is contained in:
Roberto Ierusalimschy
2020-10-06 15:50:24 -03:00
parent 9ecd446141
commit 5aa36e894f
6 changed files with 29 additions and 26 deletions
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19
ldo.c
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@@ -182,10 +182,10 @@ static void correctstack (lua_State *L, StkId oldstack, StkId newstack) {
int luaD_reallocstack (lua_State *L, int newsize, int raiseerror) {
int lim = L->stacksize;
StkId newstack = luaM_reallocvector(L, L->stack, lim, newsize, StackValue);
int lim = stacksize(L);
StkId newstack = luaM_reallocvector(L, L->stack,
lim + EXTRA_STACK, newsize + EXTRA_STACK, StackValue);
lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE);
lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK);
if (unlikely(newstack == NULL)) { /* reallocation failed? */
if (raiseerror)
luaM_error(L);
@@ -195,8 +195,7 @@ int luaD_reallocstack (lua_State *L, int newsize, int raiseerror) {
setnilvalue(s2v(newstack + lim)); /* erase new segment */
correctstack(L, L->stack, newstack);
L->stack = newstack;
L->stacksize = newsize;
L->stack_last = L->stack + newsize - EXTRA_STACK;
L->stack_last = L->stack + newsize;
return 1;
}
@@ -206,19 +205,19 @@ int luaD_reallocstack (lua_State *L, int newsize, int raiseerror) {
** is true, raises any error; otherwise, return 0 in case of errors.
*/
int luaD_growstack (lua_State *L, int n, int raiseerror) {
int size = L->stacksize;
int size = stacksize(L);
if (unlikely(size > LUAI_MAXSTACK)) {
/* if stack is larger than maximum, thread is already using the
extra space reserved for errors, that is, thread is handling
a stack error; cannot grow further than that. */
lua_assert(L->stacksize == ERRORSTACKSIZE);
lua_assert(stacksize(L) == ERRORSTACKSIZE);
if (raiseerror)
luaD_throw(L, LUA_ERRERR); /* error inside message handler */
return 0; /* if not 'raiseerror', just signal it */
}
else {
int newsize = 2 * size; /* tentative new size */
int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK;
int needed = cast_int(L->top - L->stack) + n;
if (newsize > LUAI_MAXSTACK) /* cannot cross the limit */
newsize = LUAI_MAXSTACK;
if (newsize < needed) /* but must respect what was asked for */
@@ -257,7 +256,7 @@ static int stackinuse (lua_State *L) {
** previous size, and half of its entries are empty.)
** As a particular case, if stack was handling a stack overflow and now
** it is not, 'max' (limited by LUAI_MAXSTACK) will be smaller than
** 'stacksize' (equal to ERRORSTACKSIZE in this case), and so the stack
** stacksize (equal to ERRORSTACKSIZE in this case), and so the stack
** will be reduced to a "regular" size.
*/
void luaD_shrinkstack (lua_State *L) {
@@ -271,7 +270,7 @@ void luaD_shrinkstack (lua_State *L) {
}
/* if thread is currently not handling a stack overflow and its
size is larger than maximum "reasonable" size, shrink it */
if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) && L->stacksize > max)
if (inuse <= LUAI_MAXSTACK && stacksize(L) > max)
luaD_reallocstack(L, nsize, 0); /* ok if that fails */
else /* don't change stack */
condmovestack(L,{},{}); /* (change only for debugging) */