On Apr 12, 2005, Alexandre Oliva <[EMAIL PROTECTED]> wrote:
> It looks like it wouldn't be too hard to overcome this problem by
> generating the artificial labels in case_index order, instead of in
> goto_queue order, but it's not obvious to me that the potential
> randomness from sorting of stmt addresses in the goto_queue that have
> the same index couldn't possibly affect the outcome.
This is what I had in mind with the paragraph above. Does it feel
like a reasonable approach? (Note that the two sets of
last_case_index were dead, so the patch removes them)
Index: gcc/tree-eh.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-eh.c,v
retrieving revision 2.28
diff -u -p -r2.28 tree-eh.c
--- gcc/tree-eh.c 1 Apr 2005 03:42:44 -0000 2.28
+++ gcc/tree-eh.c 12 Apr 2005 05:51:36 -0000
@@ -1194,7 +1194,6 @@ lower_try_finally_switch (struct leh_sta
q = tf->goto_queue;
qe = q + tf->goto_queue_active;
j = last_case_index + tf->may_return;
- last_case_index += nlabels;
for (; q < qe; ++q)
{
tree mod;
@@ -1217,20 +1216,37 @@ lower_try_finally_switch (struct leh_sta
case_index = j + q->index;
if (!TREE_VEC_ELT (case_label_vec, case_index))
- {
- last_case = build (CASE_LABEL_EXPR, void_type_node,
- build_int_cst (NULL_TREE, switch_id), NULL,
- create_artificial_label ());
- TREE_VEC_ELT (case_label_vec, case_index) = last_case;
-
- x = build (LABEL_EXPR, void_type_node, CASE_LABEL (last_case));
- append_to_statement_list (x, &switch_body);
- append_to_statement_list (q->cont_stmt, &switch_body);
- maybe_record_in_goto_queue (state, q->cont_stmt);
- }
+ TREE_VEC_ELT (case_label_vec, case_index)
+ = build (CASE_LABEL_EXPR, void_type_node,
+ build_int_cst (NULL_TREE, switch_id), NULL,
+ /* We store the cont_stmt in the
+ CASE_LABEL, so that we can recover it
+ in the loop below. We don't create
+ the new label while walking the
+ goto_queue because pointers don't
+ offer a stable order. */
+ q->cont_stmt);
+ }
+ for (j = last_case_index; j < last_case_index + nlabels; j++)
+ {
+ tree label;
+ tree cont_stmt;
+
+ last_case = TREE_VEC_ELT (case_label_vec, j);
+
+ gcc_assert (last_case);
+
+ cont_stmt = CASE_LABEL (last_case);
+
+ label = create_artificial_label ();
+ CASE_LABEL (last_case) = label;
+
+ x = build (LABEL_EXPR, void_type_node, label);
+ append_to_statement_list (x, &switch_body);
+ append_to_statement_list (cont_stmt, &switch_body);
+ maybe_record_in_goto_queue (state, cont_stmt);
}
replace_goto_queue (tf);
- last_case_index += nlabels;
/* Make sure that the last case is the default label, as one is required.
Then sort the labels, which is also required in GIMPLE. */
--
Alexandre Oliva http://www.ic.unicamp.br/~oliva/
Red Hat Compiler Engineer [EMAIL PROTECTED], gcc.gnu.org}
Free Software Evangelist [EMAIL PROTECTED], gnu.org}
