http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46114
Summary: [4.6 regression] g++ SEGV when built with gld on
Solaris 10+/x86
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: r...@gcc.gnu.org
CC: ber...@codesourcery.com
Host: i386-pc-solaris2.1[01]
Target: i386-pc-solaris2.1[01]
Build: i386-pc-solaris2.1[01]
When I recently tried to bootstrap mainline on Solaris 11 (and later 10)/x86
with CVS gas and gld, many C++ testcases failed. It turned out that g++
SEGVs like this:
% g++ gcc.o
Segmentation Fault
It crashes like this:
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1 (LWP 1)]
generate_option (opt_index=902, arg=0x8074535 <error reading variable>,
value=1, lang_mask=65536, decoded=0x1)
at /var/gcc/reghunt/trunk/gcc/opts-common.c:862
862 decoded->arg = arg;
(gdb) where
#0 generate_option (opt_index=902, arg=0x8074535 <error reading variable>,
value=1, lang_mask=65536, decoded=0x1)
at /var/gcc/reghunt/trunk/gcc/opts-common.c:862
#1 0x0805a9cb in lang_specific_driver (in_decoded_options=0x80474d8,
in_decoded_options_count=0x80474dc, in_added_libraries=0x8093744)
at /var/gcc/reghunt/trunk/gcc/cp/g++spec.c:324
#2 0x0804c764 in process_command (decoded_options_count=2,
decoded_options=0x8093ff8) at /var/gcc/reghunt/trunk/gcc/gcc.c:3597
#3 0x08052f9a in main (argc=2, argv=0x8047664)
at /var/gcc/reghunt/trunk/gcc/gcc.c:6214
i.e. decoded is invalid. After searching around for a binutils change that
caused this, it turned out that the problem only happens when gas and gld
are in use, but also with gas/gld 2.20.1. A gcc reghunt identified the
following patch as the culprit:
2010-09-23 Bernd Schmidt <ber...@codesourcery.com>
PR rtl-optimization/44374
* basic-block.h (enum bb_flags): Add BB_MODIFIED.
* df-core.c (df_set_bb_dirty): Set it.
* ifcvt.c (find_memory): Remove function.
(dead_or_predicable): Use can_move_insns_across.
* df.h (can_move_insns_across): Declare function.
* cfgcleanup.c (block_was_dirty): New static variable.
(try_crossjump_bb, try_forward_edges): Test BB_MODIFIED flag rather
than df_get_bb_dirty.
(try_head_merge_bb): New static function.
(try_optimize_cfg): Call it. Call df_analyze if block_was_dirty
is set.
* df-problems.c: Include "target.h"
(df_simulate_find_uses): New static function.
(MEMREF_NORMAL, MEMREF_VOLATILE): New macros.
(find_memory, find_memory_store): New static functions.
(can_move_insns_across): New function.
* Makefile.in (df-problems.o): Update dependencies.
I've not yet identified the mis-compilation caused.
