mirror/guile
mirror/guile
1
Fork 0
mirror of https://git.savannah.gnu.org/git/guile.git synced 2025-06-10 14:00:21 +02:00
Code Activity

Walk the stack to determine extent of partial continuation

Browse source 
* libguile/control.c (reify_partial_continuation): Walk the stack to
  determine the bottom of the captured stack.
This commit is contained in:
Andy Wingo 2013-10-23 17:18:24 +02:00
parent 186b56c4dc
commit 88e5caded5
1 changed files with 13 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

19
libguile/control.c
View file

@ -86,6 +86,7 @@ reify_partial_continuation (SCM vm,
{
SCM vm_cont;
scm_t_uint32 flags;
SCM *bottom_fp;
flags = SCM_F_VM_CONT_PARTIAL;
/* If we are aborting to a prompt that has the same registers as those
@ -95,15 +96,21 @@ reify_partial_continuation (SCM vm,
if (saved_registers && saved_registers == current_registers)
flags |= SCM_F_VM_CONT_REWINDABLE;
/* Since non-escape continuations should begin with a thunk application, the
first bit of the stack should be a frame, with the saved fp equal to the fp
that was current when the prompt was made. */
if ((SCM*)SCM_UNPACK (saved_sp[1]) != saved_fp)
abort ();
/* Walk the stack down until we find the first frame after saved_fp.
We will save the stack down to that frame. It used to be that we
could determine the stack bottom in O(1) time, but that's no longer
the case, since the thunk application doesn't occur where the
prompt is saved. */
for (bottom_fp = SCM_VM_DATA (vm)->fp;
SCM_FRAME_DYNAMIC_LINK (bottom_fp) > saved_fp;
bottom_fp = SCM_FRAME_DYNAMIC_LINK (bottom_fp));
if (SCM_FRAME_DYNAMIC_LINK (bottom_fp) != saved_fp)
abort();
/* Capture from the top of the thunk application frame up to the end. Set an
MVRA only, as the post-abort code is in an MV context. */
vm_cont = scm_i_vm_capture_stack (saved_sp + 4,
vm_cont = scm_i_vm_capture_stack (bottom_fp - 1,
SCM_VM_DATA (vm)->fp,
SCM_VM_DATA (vm)->sp,
NULL,