Use SSize_t for tmps stack offsets

This is a partial fix for #119161.

On 64-bit platforms, I32 is too small to hold offsets into a stack
that can grow larger than I32_MAX.  What happens is the offsets can
wrap so we end up referencing and modifying elements with negative
indices, corrupting memory, and causing crashes.

With this commit, ()=1..1000000000000 stops crashing immediately.
Instead, it gobbles up all your memory first, and then, if your com-
puter still survives, crashes.  The second crash happesn bcause of
a similar bug with the argument stack, which the next commit will
take care of.

1 files changed, 1 insertions, 1 deletions

diff --git a/op.c b/op.c
index 6776dc7dd6..3b990e264a 100644
--- a/op.c
+++ b/op.c
@@ -3355,7 +3355,7 @@ S_gen_constant_list(pTHX_ OP *o)
 {
     dVAR;
     OP *curop;
-    const I32 oldtmps_floor = PL_tmps_floor;
+    const SSize_t oldtmps_floor = PL_tmps_floor;
     SV **svp;
     AV *av;