Small corrections when setting 'L->top'
- OP_NEWTABLE can use 'ra + 1' to set top (instead of ci->top);
- OP_CLOSE doesn't need to set top ('Protect' already does that);
- OP_TFORCALL must use 'ProtectNT', to preserve the top already set.
(That was a small bug, because iterators could be called with
extra parameters besides the state and the control variable.)
- Comments and an extra test for the bug in previous item.
diff --git a/lapi.h b/lapi.h
index 5a4206f..f48d14f 100644
--- a/lapi.h
+++ b/lapi.h
@@ -11,12 +11,22 @@
#include "llimits.h"
#include "lstate.h"
+
+/* Increments 'L->top', checking for stack overflows */
#define api_incr_top(L) {L->top++; api_check(L, L->top <= L->ci->top, \
"stack overflow");}
+
+/*
+** If a call returns too many multiple returns, the callee may not have
+** stack space to accomodate all results. In this case, this macro
+** increases its stack space ('L->ci->top').
+*/
#define adjustresults(L,nres) \
{ if ((nres) <= LUA_MULTRET && L->ci->top < L->top) L->ci->top = L->top; }
+
+/* Ensure the stack has at least 'n' elements */
#define api_checknelems(L,n) api_check(L, (n) < (L->top - L->ci->func), \
"not enough elements in the stack")
diff --git a/lparser.c b/lparser.c
index b70c609..7447222 100644
--- a/lparser.c
+++ b/lparser.c
@@ -694,9 +694,10 @@
/*
** codes instruction to create new closure in parent function.
-** The OP_CLOSURE instruction must use the last available register,
+** The OP_CLOSURE instruction uses the last available register,
** so that, if it invokes the GC, the GC knows which registers
** are in use at that time.
+
*/
static void codeclosure (LexState *ls, expdesc *v) {
FuncState *fs = ls->fs->prev;
diff --git a/lvm.c b/lvm.c
index d9bd0ab..26477c2 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1258,7 +1258,7 @@
if (TESTARG_k(i))
c += GETARG_Ax(*pc) * (MAXARG_C + 1);
pc++; /* skip extra argument */
- L->top = ci->top; /* correct top in case of GC */
+ L->top = ra + 1; /* correct top in case of emergency GC */
t = luaH_new(L); /* memory allocation */
sethvalue2s(L, ra, t);
if (b != 0 || c != 0)
@@ -1478,7 +1478,6 @@
vmbreak;
}
vmcase(OP_CLOSE) {
- L->top = ra + 1; /* everything is free after this slot */
Protect(luaF_close(L, ra, LUA_OK));
vmbreak;
}
@@ -1755,7 +1754,7 @@
/* push function, state, and control variable */
memcpy(ra + 4, ra, 3 * sizeof(*ra));
L->top = ra + 4 + 3;
- Protect(luaD_call(L, ra + 4, GETARG_C(i))); /* do the call */
+ ProtectNT(luaD_call(L, ra + 4, GETARG_C(i))); /* do the call */
updatestack(ci); /* stack may have changed */
i = *(pc++); /* go to next instruction */
lua_assert(GET_OPCODE(i) == OP_TFORLOOP && ra == RA(i));
@@ -1776,7 +1775,7 @@
if (n == 0)
n = cast_int(L->top - ra) - 1; /* get up to the top */
else
- L->top = ci->top; /* correct top in case of GC */
+ L->top = ci->top; /* correct top in case of emergency GC */
last += n;
if (TESTARG_k(i)) {
last += GETARG_Ax(*pc) * (MAXARG_C + 1);
diff --git a/testes/nextvar.lua b/testes/nextvar.lua
index a7fe625..9d91963 100644
--- a/testes/nextvar.lua
+++ b/testes/nextvar.lua
@@ -671,7 +671,8 @@
local function f (n, p)
local t = {}; for i=1,p do t[i] = i*10 end
- return function (_,n)
+ return function (_, n, ...)
+ assert(select("#", ...) == 0) -- no extra arguments
if n > 0 then
n = n-1
return n, table.unpack(t)
