From 7fe1a4cff3998bf019144924f39aec3f76a5cf32 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Thu, 8 Sep 2016 13:36:26 -0300 Subject: cleaner and more correct code for 'luaD_shrinkstack' (the old test "inuse <= LUAI_MAXSTACK" for stack overflow is not correct, as the real maximum usable size is "LUAI_MAXSTACK - EXTRA_STACK") --- ldo.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/ldo.c b/ldo.c index 87f95bbd..cc5be57b 100644 --- a/ldo.c +++ b/ldo.c @@ -221,14 +221,17 @@ static int stackinuse (lua_State *L) { void luaD_shrinkstack (lua_State *L) { int inuse = stackinuse(L); int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; - if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; - if (L->stacksize > LUAI_MAXSTACK) /* was handling stack overflow? */ + if (goodsize > LUAI_MAXSTACK) + goodsize = LUAI_MAXSTACK; /* respect stack limit */ + if (L->stacksize > LUAI_MAXSTACK) /* had been handling stack overflow? */ luaE_freeCI(L); /* free all CIs (list grew because of an error) */ else luaE_shrinkCI(L); /* shrink list */ - if (inuse <= LUAI_MAXSTACK && /* not handling stack overflow? */ - goodsize < L->stacksize) /* trying to shrink? */ - luaD_reallocstack(L, goodsize); /* shrink it */ + /* if thread is currently not handling a stack overflow and its + good size is smaller than current size, shrink its stack */ + if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) && + goodsize < L->stacksize) + luaD_reallocstack(L, goodsize); else condmovestack(L,,); /* don't change stack (change only for debugging) */ } -- cgit v1.2.3-55-g6feb