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authorAndy Wingo <wingo@pobox.com>2010-02-26 13:05:25 +0100
committerAndy Wingo <wingo@pobox.com>2010-02-26 13:05:25 +0100
commitadbdfd6d2418b1404af48d480c2273f501517d6e (patch)
tree9624620bcedfbdd1cc29a9454b2cbcfdebdf808b /libguile/vm.c
parent416f26c7534a018c59f1c8d888dc9153f42d86d1 (diff)
downloadguile-adbdfd6d2418b1404af48d480c2273f501517d6e.tar.gz
rewinding prompts works
* libguile/control.h (SCM_PROMPT_HANDLER): Remove, it was unused. (SCM_PROMPT_DYNWINDS): Rename from SCM_PROMPT_DYNENV. * libguile/control.c: (scm_c_make_prompt): Take another arg, the winds that are to be in place for the prompt. Fix allocation to be 4 words instead of 5 (the handler was never used). * libguile/eval.c (eval): * libguile/throw.c (pre_init_catch): Adapt to scm_c_make_prompt change. * libguile/vm-i-system.c (partial-cont-call): Grovel the new elements of the wind list in order to call setjmp() on the new prompts. Pass cookie to vm_reinstate_partial_continuation. (prompt): Adapt to scm_c_make_prompt change. * libguile/vm.c (vm_reinstate_partial_continuation): Take a cookie arg, used when winding captured prompts onto the stack. Winding a prompt implies making a new prompt, actually -- with new registers, a new jump buffer, new winds, etc. * test-suite/tests/control.test ("rewinding prompts"): Add a test for rewinding prompts.
Diffstat (limited to 'libguile/vm.c')
-rw-r--r--libguile/vm.c26
1 files changed, 21 insertions, 5 deletions
diff --git a/libguile/vm.c b/libguile/vm.c
index 85e0e7ada..142061185 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -231,7 +231,7 @@ vm_abort (SCM vm, size_t n, scm_t_int64 vm_cookie)
static void
vm_reinstate_partial_continuation (SCM vm, SCM cont, SCM intwinds,
- size_t n, SCM *argv)
+ size_t n, SCM *argv, scm_t_int64 vm_cookie)
{
struct scm_vm *vp;
struct scm_vm_cont *cp;
@@ -267,8 +267,6 @@ vm_reinstate_partial_continuation (SCM vm, SCM cont, SCM intwinds,
vp->fp = RELOC (cp->fp);
vp->ip = cp->mvra;
-#undef RELOC
-
/* now push args. ip is in a MV context. */
for (i = 0; i < n; i++)
{
@@ -278,14 +276,32 @@ vm_reinstate_partial_continuation (SCM vm, SCM cont, SCM intwinds,
vp->sp++;
*vp->sp = scm_from_size_t (n);
- /* Finally, rewind the dynamic state. */
+ /* Finally, rewind the dynamic state.
+
+ We have to treat prompts specially, because we could be rewinding the
+ dynamic state from a different thread, or just a different position on the
+ C and/or VM stack -- so we need to reset the jump buffers so that an abort
+ comes back here, with appropriately adjusted sp and fp registers. */
{
long delta = 0;
SCM newwinds = scm_i_dynwinds ();
for (; scm_is_pair (intwinds); intwinds = scm_cdr (intwinds), delta--)
- newwinds = scm_cons (scm_car (intwinds), newwinds);
+ {
+ SCM x = scm_car (intwinds);
+ if (SCM_PROMPT_P (x))
+ /* the jmpbuf will be reset by our caller */
+ x = scm_c_make_prompt (SCM_PROMPT_TAG (x),
+ RELOC (SCM_PROMPT_REGISTERS (x)->fp),
+ RELOC (SCM_PROMPT_REGISTERS (x)->sp),
+ SCM_PROMPT_REGISTERS (x)->ip,
+ SCM_PROMPT_ESCAPE_P (x),
+ vm_cookie,
+ newwinds);
+ newwinds = scm_cons (x, newwinds);
+ }
scm_dowinds (newwinds, delta);
}
+#undef RELOC
}