+ XSH_D(xsh_debug_log("%p: ### su_pop: depth=%d\n", ud, depth));
+
+ depth--;
+ mark = PL_savestack_ix;
+ base = origin[depth].orig_ix;
+
+ XSH_D(xsh_debug_log("%p: residual savestack frame is %d(+%d)..%d\n",
+ ud, base, origin[depth].offset, mark));
+
+ if (base < mark) {
+ XSH_D(xsh_debug_log("%p: clear leftovers at %d..%d\n", ud, base, mark));
+ leave_scope(base);
+ }
+ assert(PL_savestack_ix == base);
+
+ SU_UD_DEPTH(ud) = depth;
+
+ if (depth > 0) {
+ su_ss_push_destructor(ud, depth-1, 0);
+ } else {
+ I32 offset = origin[0].offset; /* grab value before origin is freed */
+ switch (SU_UD_TYPE(ud)) {
+ case SU_UD_TYPE_REAP: {
+ XSH_D(
+ xsh_debug_log("%p: === reap\n%p: depth=%d scope_ix=%d save_ix=%d\n",
+ ud, ud, SU_UD_DEPTH(ud), PL_scopestack_ix, PL_savestack_ix)
+ );
+ SAVEDESTRUCTOR_X(su_call, SU_UD_REAP_CB(ud));
+ SU_UD_FREE(ud);
+ break;
+ }
+ case SU_UD_TYPE_LOCALIZE:
+ su_localize(ud);
+ SU_UD_LOCALIZE_FREE(ud);
+ break;
+ case SU_UD_TYPE_UID:
+ SAVEDESTRUCTOR_X(su_uid_drop, ud);
+ break;
+ }
+ /* perl 5.23.8 onwards is very fussy about the return from leave_scope()
+ * leaving PL_savestack_ix where it expects it to be */
+ if (PL_savestack_ix < base + offset) {
+ I32 gap = (base + offset) - PL_savestack_ix;
+ assert(gap >= SU_SAVE_ALLOC_SIZE + 1);
+ su_ss_push_padding(ud, gap);
+ }
+ assert(PL_savestack_ix == base + offset);
+ }
+
+ XSH_D(xsh_debug_log("%p: end pop: ss_ix=%d\n", ud, PL_savestack_ix));
+}
+
+/* --- Initialize the stack and the action userdata ------------------------ */
+
+static void su_init(pTHX_ void *ud, I32 cxix, I32 size) {
+#define su_init(U, C, S) su_init(aTHX_ (U), (C), (S))
+ su_ud_origin_elem *origin;
+ I32 i, depth;
+ I32 cur_cx_ix, cur_scope_ix;
+
+ XSH_D(xsh_debug_log("%p: ### su_init(cxix=%d, size=%d)\n", ud, cxix, size));
+
+ depth = PL_scopestack_ix - cxstack[cxix].blk_oldscopesp;
+#if SU_HAS_NEW_CXT
+ depth += (cxstack_ix - cxix); /* each context frame holds 1 scope */
+#endif
+ XSH_D(xsh_debug_log(
+ "%p: going down by depth=%d with scope_ix=%d save_ix=%d\n",
+ ud, depth, PL_scopestack_ix, PL_savestack_ix));
+
+ /* Artificially increase the position of each savestack frame boundary
+ * to make space to squeeze in a 'size' sized entry (first one) or a
+ * SU_SAVE_DESTRUCTOR_SIZE sized entry (higher ones). In addition, make
+ * sure that each boundary is higher than the previous, so that *every*
+ * scope exit triggers a call to leave_scope(). Each scope exit will call
+ * the su_pop() destructor, which is responsible for: freeing any
+ * savestack entries below the artificially raised floor; then pushing a
+ * new destructor in that space. On the final pop, the "real" savestack
+ * action is pushed rather than another destructor.
+ *
+ * On older perls, savestack frame boundaries are specified by a range of
+ * scopestack entries (one per ENTER). Each scope entry typically does
+ * one or two ENTERs followed by a PUSHBLOCK. Thus the
+ * cx->blku_oldscopesp field set by the PUSHBLOCK points to the next free
+ * slot, which is one above the last of the ENTERs. In the debugging
+ * output we indicate that by bracketing the ENTERs directly preceding
+ * that context push with dashes, e.g.:
+ *
+ * 13b98d8: ------------------
+ * 13b98d8: ENTER origin[0] scope[3] savestack=3+3
+ * 13b98d8: ENTER origin[1] scope[4] savestack=9+3
+ * 13b98d8: cx=1 LOOP_LAZYIV
+ * 13b98d8: ------------------
+ *
+ * In addition to context stack pushes, other activities can push ENTERs
+ * too, such as grep expr and XS sub calls.
+ *
+ * For newer perls (SU_HAS_NEW_CXT), a context push no longer does any
+ * ENTERs; instead the old savestack position is stored in the new
+ * cx->blk_oldsaveix field; thus this field specifies an additional
+ * savestack frame boundary point in addition to the scopestack entries,
+ * and will also need adjusting.
+ *
+ * We record the original and modified position of each boundary in the
+ * origin array.
+ *
+ * The passed cxix argument represents the scope we wish to inject into;
+ * we have to adjust all the savestack frame boundaries above (but not
+ * including) that context.
+ */
+
+ Newx(origin, depth, su_ud_origin_elem);
+
+ cur_cx_ix = cxix;
+ cur_scope_ix = cxstack[cxix].blk_oldscopesp;
+
+#if SU_HAS_NEW_CXT
+ XSH_D(xsh_debug_log("%p: cx=%-2d %-11s\n",
+ ud, cur_cx_ix, SU_CXNAME(cxstack+cur_cx_ix)));
+ cur_cx_ix++;
+#endif
+
+ for (i = 0; cur_scope_ix < PL_scopestack_ix; i++) {
+ I32 *ixp;
+ I32 offset;
+
+#if SU_HAS_NEW_CXT
+
+ if (cur_cx_ix <= cxstack_ix
+ && cur_scope_ix == cxstack[cur_cx_ix].blk_oldscopesp)
+ ixp = &(cxstack[cur_cx_ix++].blk_oldsaveix);
+ else
+ ixp = &PL_scopestack[cur_scope_ix++]; /* an ENTER pushed after cur context */
+
+#else
+
+ XSH_D({
+ if (cur_cx_ix <= cxstack_ix) {
+ if (cur_scope_ix == cxstack[cur_cx_ix].blk_oldscopesp) {
+ xsh_debug_log("%p: cx=%-2d %s\n%p: ------------------\n",
+ ud, cur_cx_ix, SU_CXNAME(cxstack+cur_cx_ix), ud);
+ cur_cx_ix++;
+ }
+ else if (cur_scope_ix + su_cxt_enter_count[CxTYPE(cxstack+cur_cx_ix)]
+ == cxstack[cur_cx_ix].blk_oldscopesp)
+ xsh_debug_log("%p: ------------------\n", ud);
+ }
+ });
+
+ ixp = &PL_scopestack[cur_scope_ix++];
+
+#endif
+
+ if (i == 0) {
+ offset = size;
+ } else {
+ /* we have three constraints to satisfy:
+ * 1) Each adjusted offset must be at least SU_SAVE_DESTRUCTOR_SIZE
+ * above its unadjusted boundary, so that there is space to inject a
+ * destructor into the outer scope.
+ * 2) Each adjusted boundary must be at least SU_SAVE_DESTRUCTOR_SIZE
+ * higher than the previous adjusted boundary, so that a new
+ * destructor can be added below the Nth adjusted frame boundary,
+ * but be within the (N-1)th adjusted frame and so be triggered on
+ * the next scope exit;
+ * 3) If the adjustment needs to be greater than SU_SAVE_DESTRUCTOR_SIZE,
+ * then it should be greater by an amount of at least the minimum
+ * pad side, so a destructor and padding can be pushed.
+ */
+ I32 pad;
+ offset = SU_SAVE_DESTRUCTOR_SIZE; /* rule 1 */
+ pad = (origin[i-1].orig_ix + origin[i-1].offset) + offset
+ - (*ixp + offset);
+ if (pad > 0) { /* rule 2 */
+ if (pad < SU_SAVE_ALLOC_SIZE + 1) /* rule 3 */
+ pad = SU_SAVE_ALLOC_SIZE + 1;
+ offset += pad;
+ }
+ }
+
+ origin[i].offset = offset;
+ origin[i].orig_ix = *ixp;
+ *ixp += offset;
+
+#if SU_HAS_NEW_CXT
+ XSH_D({
+ if (ixp == &PL_scopestack[cur_scope_ix-1])
+ xsh_debug_log(
+ "%p: ENTER origin[%d] scope[%d] savestack=%d+%d\n",
+ ud, i, cur_scope_ix, origin[i].orig_ix, origin[i].offset);
+ else
+ xsh_debug_log(
+ "%p: cx=%-2d %-11s origin[%d] scope[%d] savestack=%d+%d\n",
+ ud, cur_cx_ix-1, SU_CXNAME(cxstack+cur_cx_ix-1),
+ i, cur_scope_ix, origin[i].orig_ix, origin[i].offset);
+ });
+#else
+ XSH_D(xsh_debug_log(
+ "%p: ENTER origin[%d] scope[%d] savestack=%d+%d\n",
+ ud, i, cur_scope_ix, origin[i].orig_ix, origin[i].offset));
+#endif
+
+ }
+
+ assert(i == depth);
+
+ SU_UD_DEPTH(ud) = depth;
+ SU_UD_ORIGIN(ud) = origin;
+
+ su_ss_push_destructor(ud, depth-1, 1);
+}
+
+/* --- Unwind stack -------------------------------------------------------- */
+
+static void su_unwind(pTHX_ void *ud_) {
+ dXSH_CXT;
+ I32 cxix = XSH_CXT.unwind_storage.cxix;
+ I32 items = XSH_CXT.unwind_storage.items;
+ I32 mark;
+
+ PERL_UNUSED_VAR(ud_);
+
+ PL_stack_sp = XSH_CXT.unwind_storage.savesp;
+#if XSH_HAS_PERL(5, 19, 4)
+ {
+ I32 i;
+ SV **sp = PL_stack_sp;
+ for (i = -items + 1; i <= 0; ++i)
+ if (!SvTEMP(sp[i]))
+ sv_2mortal(SvREFCNT_inc(sp[i]));
+ }
+#endif