From 980f45b6937f7ffe4d6283f9acddcfd1105fa4e4 Mon Sep 17 00:00:00 2001 From: kristerw Date: Mon, 16 Dec 2002 19:33:50 +0000 Subject: [PATCH] Place EH labels on the permanent obstack. Fixes PR 18314. Background: Originally, the EH labels were placed on the permanent obstack, which could end up using a lot of memory (for heavy inlining) since inlined labels also needed to be permanent as a result of this. This was changed in Wed Dec 9 09:12:40 1998 Andrew MacLeod * except.h (struct handler_info): Add handler_number field. * except.c (gen_exception_label): EH labels no longer need to be on the permanent obstack. (get_new_handler): Set the label number field. (output_exception_table_entry): Regenerate handler label reference from the label number field. (init_eh): Remove a blank line. * integrate.c (get_label_from_map): Labels no longer need to be on the permanent obstack. by using the label numbers instead of the label structures in most cases. The operative word here is "most" cases. Addresses to the EH RTX was still used in (at least) flow.c, that now used freed memory. Oops. For this to happen, the freed address of the RTX representing a EH label must be reused for a new label that is located in dead code. delete_block() will then see that this RTX is mentioned in the EH table, and (incorrectly) remove the exception handler. This might be seen when, for example, compiling src/gnu/dist/groff/src/roff/troff/node.cc for m68k. --- gnu/dist/toolchain/gcc/except.c | 4 ++++ gnu/dist/toolchain/gcc/integrate.c | 7 ++++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/gnu/dist/toolchain/gcc/except.c b/gnu/dist/toolchain/gcc/except.c index f7d78d687eff..a5ca66396734 100644 --- a/gnu/dist/toolchain/gcc/except.c +++ b/gnu/dist/toolchain/gcc/except.c @@ -617,7 +617,11 @@ rtx gen_exception_label () { rtx lab; + + push_obstacks_nochange (); + end_temporary_allocation (); lab = gen_label_rtx (); + pop_obstacks (); return lab; } diff --git a/gnu/dist/toolchain/gcc/integrate.c b/gnu/dist/toolchain/gcc/integrate.c index 33a96c40f918..f1d220a1c4b8 100644 --- a/gnu/dist/toolchain/gcc/integrate.c +++ b/gnu/dist/toolchain/gcc/integrate.c @@ -110,7 +110,12 @@ get_label_from_map (map, i) rtx x = map->label_map[i]; if (x == NULL_RTX) - x = map->label_map[i] = gen_label_rtx(); + { + push_obstacks_nochange (); + end_temporary_allocation (); + x = map->label_map[i] = gen_label_rtx(); + pop_obstacks (); + } return x; }