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VM never extends vp->sp beyond mapped region of stack

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* libguile/vm-engine.c (ALLOC_FRAME): Fold CHECK_OVERFLOW into this
  routine, and rework to not extend vp->sp until the stack has been
  expanded.

* libguile/vm.c (vm_increase_sp): Likewise, don't extend vp->sp until
  the stack has expanded.
  (vm_expand_stack): Rework to take the new stack pointer as an
  argument, and also to update vp->sp_max_since_gc and vp->sp.
This commit is contained in:
Andy Wingo 2014-02-20 10:17:51 +01:00
parent 7e2fd4e7f5
commit c2ae85beab
2 changed files with 33 additions and 44 deletions
Download patch file Download diff file Expand all files Collapse all files

23
libguile/vm.c
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@ -64,7 +64,7 @@ static SCM sym_debug;
/* #define VM_ENABLE_PARANOID_ASSERTIONS */
static void vm_expand_stack (struct scm_vm *vp) SCM_NOINLINE;
static void vm_expand_stack (struct scm_vm *vp, SCM *new_sp) SCM_NOINLINE;
/* RESTORE is for the case where we know we have done a PUSH of equal or
greater stack size in the past. Otherwise PUSH is the thing, which
@ -74,13 +74,16 @@ enum vm_increase_sp_kind { VM_SP_PUSH, VM_SP_RESTORE };
static inline void
vm_increase_sp (struct scm_vm *vp, SCM *new_sp, enum vm_increase_sp_kind kind)
{
vp->sp = new_sp;
if (new_sp > vp->sp_max_since_gc)
if (new_sp <= vp->sp_max_since_gc)
{
vp->sp_max_since_gc = new_sp;
if (kind == VM_SP_PUSH && new_sp >= vp->stack_limit)
vm_expand_stack (vp);
vp->sp = new_sp;
return;
}
if (kind == VM_SP_PUSH && new_sp >= vp->stack_limit)
vm_expand_stack (vp, new_sp);
else
vp->sp_max_since_gc = vp->sp = new_sp;
}
static inline void
@ -989,9 +992,9 @@ scm_i_vm_free_stack (struct scm_vm *vp)
}
static void
vm_expand_stack (struct scm_vm *vp)
vm_expand_stack (struct scm_vm *vp, SCM *new_sp)
{
scm_t_ptrdiff stack_size = vp->sp + 1 - vp->stack_base;
scm_t_ptrdiff stack_size = new_sp + 1 - vp->stack_base;
if (stack_size > hard_max_stack_size)
{
@ -1028,7 +1031,6 @@ vm_expand_stack (struct scm_vm *vp)
SCM *fp;
if (vp->fp)
vp->fp += reloc;
vp->sp += reloc;
vp->sp_max_since_gc += reloc;
fp = vp->fp;
while (fp)
@ -1042,6 +1044,8 @@ vm_expand_stack (struct scm_vm *vp)
fp = next_fp;
}
}
new_sp += reloc;
}
if (stack_size >= vp->max_stack_size)
@ -1068,6 +1072,7 @@ vm_expand_stack (struct scm_vm *vp)
}
/* Otherwise continue, with the new enlarged stack. */
vp->sp_max_since_gc = vp->sp = new_sp;
}
static struct scm_vm *