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Remove VM_ENABLE_STACK_NULLING

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* libguile/vm.c: Remove code dependent on VM_ENABLE_STACK_NULLING.  This
  defined didn't work and doesn't apply to the RTL model.
This commit is contained in:
Andy Wingo 2013-11-19 21:47:55 +01:00
parent 4cbc95f150
commit c4f7923fa9
1 changed files with 0 additions and 32 deletions
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32
libguile/vm.c
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@ -54,19 +54,8 @@ static SCM sym_debug;
necessary, but might be if you think you found a bug in the VM. */
#define VM_ENABLE_ASSERTIONS
/* We can add a mode that ensures that all stack items above the stack pointer
are NULL. This is useful for checking the internal consistency of the VM's
assumptions and its operators, but isn't necessary for normal operation. It
will ensure that assertions are enabled. Slows down the VM by about 30%. */
/* NB! If you enable this, search for NULLING in throw.c */
/* #define VM_ENABLE_STACK_NULLING */
/* #define VM_ENABLE_PARANOID_ASSERTIONS */
#if defined (VM_ENABLE_STACK_NULLING) && !defined (VM_ENABLE_ASSERTIONS)
#define VM_ENABLE_ASSERTIONS
#endif
/* When defined, arrange so that the GC doesn't scan the VM stack beyond its
current SP. This should help avoid excess data retention. See
http://thread.gmane.org/gmane.comp.programming.garbage-collection.boehmgc/3001
@ -112,15 +101,6 @@ scm_i_vm_capture_stack (SCM *stack_base, SCM *fp, SCM *sp, scm_t_uint32 *ra,
p->stack_size = sp - stack_base + 1;
p->stack_base = scm_gc_malloc (p->stack_size * sizeof (SCM),
"capture_vm_cont");
#if defined(VM_ENABLE_STACK_NULLING) && 0
/* Tail continuations leave their frame on the stack for subsequent
application, but don't capture the frame -- so there are some elements on
the stack then, and this check doesn't work, so disable it for now. */
if (sp >= vp->stack_base)
if (!vp->sp[0] || vp->sp[1])
abort ();
memset (p->stack_base, 0, p->stack_size * sizeof (SCM));
#endif
p->ra = ra;
p->sp = sp;
p->fp = fp;
@ -148,15 +128,6 @@ vm_return_to_continuation (SCM vm, SCM cont, size_t n, SCM *argv)
scm_misc_error ("vm-engine", "not enough space to reinstate continuation",
scm_list_2 (vm, cont));
#ifdef VM_ENABLE_STACK_NULLING
{
scm_t_ptrdiff nzero = (vp->sp - cp->sp);
if (nzero > 0)
memset (vp->stack_base + cp->stack_size, 0, nzero * sizeof (SCM));
/* actually nzero should always be negative, because vm_reset_stack will
unwind the stack to some point *below* this continuation */
}
#endif
vp->sp = cp->sp;
vp->fp = cp->fp;
memcpy (vp->stack_base, cp->stack_base, cp->stack_size * sizeof (SCM));
@ -808,9 +779,6 @@ make_vm (void)
"stack-base");
#endif
#ifdef VM_ENABLE_STACK_NULLING
memset (vp->stack_base, 0, vp->stack_size * sizeof (SCM));
#endif
vp->stack_limit = vp->stack_base + vp->stack_size - VM_STACK_RESERVE_SIZE;
vp->ip = NULL;
vp->sp = vp->stack_base - 1;