From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32402 invoked by alias); 15 Oct 2011 20:49:38 -0000 Received: (qmail 32392 invoked by uid 22791); 15 Oct 2011 20:49:37 -0000 X-SWARE-Spam-Status: No, hits=-2.8 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,TW_EG X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sat, 15 Oct 2011 20:49:23 +0000 From: "ebotcazou at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/50678] [4.7 Regression] FAIL: c52104y on x86_64-apple-darwin10 Date: Sat, 15 Oct 2011 20:49:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: ebotcazou at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P4 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.7.0 X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2011-10/txt/msg01485.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50678 --- Comment #30 from Eric Botcazou 2011-10-15 20:49:03 UTC --- > however I've not got far through Raise_From_Signal_Handler () - if one > continues from there it ends with a loop on x86-64/darwin9 and another segv on > x86-64/darwin10. You need to compile with -fstack-check. Then you'll be able to debug the unwinding phase. Here are some possible breakpoints: 0x00007fff85b7a260 in unw_init_local () from /usr/lib/libSystem.B.dylib (gdb) disass Dump of assembler code for function unw_init_local: Breakpoint 3, 0x00007fff85b9fe32 in unwind_phase2 () from /usr/lib/libSystem.B.dylib (gdb) disass Dump of assembler code for function unwind_phase2: 0x00007fff85ba0150 in libunwind::Registers_x86_64::jumpto() () from /usr/lib/libSystem.B.dylib (gdb) disass Dump of assembler code for function _ZN9libunwind16Registers_x86_646jumptoEv: => 0x00007fff85ba0150 <+0>: mov 0x38(%rdi),%rax The context from which jumpto restores the registers has the wrong %rbx line. > The thing that's itching slightly is that there is a syscall (in > __gnat_error_handler ) to switch the signal stack - before the raise, and I > wonder if the use of the alt sigstack is what's causing the problem. This call doesn't actually do anything. The stack is switched by the system before __gnat_error_handler is entered and all the processing is done using the alternate stack, until execution is resumed in the exception handler. > One would imagine that anything as radical as a missing reg. save/rest in eh > would be spotted outside Ada ;-) Java is the only other language that supports this kind of things though.