def get_result_suspstack(h):
# Now we are in the target, after the switch() or the new().
# Note that this whole module was carefully written in such a way as
# not to invoke pushing/popping things off the shadowstack at
# unexpected moments...
oldsuspstack = gcrootfinder.oldsuspstack
newsuspstack = gcrootfinder.newsuspstack
gcrootfinder.oldsuspstack = NULL_SUSPSTACK
gcrootfinder.newsuspstack = NULL_SUSPSTACK
if not h:
raise MemoryError
# We still have the old shadowstack active at this point; save it
# away, and restore the new one
if oldsuspstack:
ll_assert(not _c.is_empty_handle(h),"unexpected empty stacklet handle")
h = llmemory.cast_ptr_to_adr(h)
llop.gc_save_current_state_away(lltype.Void, oldsuspstack, h)
else:
ll_assert(_c.is_empty_handle(h),"unexpected non-empty stacklet handle")
llop.gc_forget_current_state(lltype.Void)
#
llop.gc_restore_state_from(lltype.Void, newsuspstack)
#
# From this point on, 'newsuspstack' is consumed and done, its
# shadow stack installed as the current one. It should not be
# used any more. For performance, we avoid it being deallocated
# by letting it be reused on the next switch.
gcrootfinder.oldsuspstack = newsuspstack
# Return.
return oldsuspstack
def _new_callback(h, arg):
# We still have the old shadowstack active at this point; save it
# away, and start a fresh new one
oldsuspstack = gcrootfinder.oldsuspstack
h = llmemory.cast_ptr_to_adr(h)
llop.gc_save_current_state_away(lltype.Void,
oldsuspstack, h)
llop.gc_start_fresh_new_state(lltype.Void)
gcrootfinder.oldsuspstack = NULL_SUSPSTACK
#
newsuspstack = gcrootfinder.callback(oldsuspstack, arg)
#
# Finishing this stacklet.
gcrootfinder.oldsuspstack = NULL_SUSPSTACK
gcrootfinder.newsuspstack = newsuspstack
h = llop.gc_shadowstackref_context(llmemory.Address, newsuspstack)
return llmemory.cast_adr_to_ptr(h, _c.handle)
