Clear stack area below revived continuation.

* unwind.c (revive_cont): Don't just reserve frame_slack
bytes below the continuation for any stack frame, but
clear the bytes to zero. On Cygwin, this fixes a failing
continuation test case. The issue is that the cont_obj
variable in capture_cont lands into this area (implying
it is not captured). When the continuation is revived,
the variable has a garbage value, rather than nil,
as expected.

1 files changed, 1 insertions, 0 deletions

diff --git a/unwind.c b/unwind.c
index cf242b20..3846fa5c 100644
--- a/unwind.c
+++ b/unwind.c
@@ -744,6 +744,7 @@ static val revive_cont(val dc, val arg)
     uw_frame_t *new_uw_stack = coerce(uw_frame_t *, space), *fr;
     int env_set = 0;
 
+    memset(space - frame_slack, 0, frame_slack);
     memcpy(space, cont->stack, cont->size);
 
     for (ptr = space; ptr < space + cont->size; ptr += sizeof (cnum))