Please add support for unwinding through signal handler for GNU/kFreeBSD.
The attached patch is tested on GNU/kFreeBSD, both 32-bit and 64-bit.
The i386/freebsd-unwind.h is probably also suitable for plain FreeBSD.
As suggested in http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57851
I am posting it here.
The patch mainly add new libgcc/config/i386/freebsd-unwind.h
based on linux one.
Thanks
Petr#
# unwinding via signal trampoline
#
--- a/src/libgcc/config.host
+++ b/src/libgcc/config.host
@@ -523,7 +523,12 @@
tmake_file="${tmake_file} i386/t-crtpc i386/t-crtfm i386/t-crtstuff
t-dfprules"
md_unwind_header=i386/linux-unwind.h
;;
-i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-knetbsd*-gnu | i[34567]86-*-gnu* |
i[34567]86-*-kopensolaris*-gnu)
+i[34567]86-*-kfreebsd*-gnu)
+ extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
+ tmake_file="${tmake_file} i386/t-crtpc i386/t-crtfm i386/t-crtstuff
t-dfprules"
+ md_unwind_header=i386/freebsd-unwind.h
+ ;;
+i[34567]86-*-knetbsd*-gnu | i[34567]86-*-gnu* | i[34567]86-*-kopensolaris*-gnu)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc i386/t-crtfm i386/t-crtstuff
t-dfprules"
;;
@@ -532,7 +537,12 @@
tmake_file="${tmake_file} i386/t-crtpc i386/t-crtfm i386/t-crtstuff
t-dfprules"
md_unwind_header=i386/linux-unwind.h
;;
-x86_64-*-kfreebsd*-gnu | x86_64-*-knetbsd*-gnu)
+x86_64-*-kfreebsd*-gnu)
+ extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
+ tmake_file="${tmake_file} i386/t-crtpc i386/t-crtfm i386/t-crtstuff
t-dfprules"
+ md_unwind_header=i386/freebsd-unwind.h
+ ;;
+x86_64-*-knetbsd*-gnu)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc i386/t-crtfm i386/t-crtstuff
t-dfprules"
;;
--- a/src/libgcc/config/i386/freebsd-unwind.h
+++ b/src/libgcc/config/i386/freebsd-unwind.h
@@ -0,0 +1,190 @@
+/* DWARF2 EH unwinding support for AMD x86-64 and x86.
+ Copyright (C) 2004-2013 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+/* Do code reading to identify a signal frame, and set the frame
+ state data appropriately. See unwind-dw2.c for the structs.
+ Don't use this at all if inhibit_libc is used. */
+
+#ifndef inhibit_libc
+
+#include <signal.h>
+#include <sys/ucontext.h>
+#include <machine/sigframe.h>
+
+#ifdef __x86_64__
+
+#define MD_FALLBACK_FRAME_STATE_FOR x86_64_fb_fallback_frame_state
+
+static _Unwind_Reason_Code
+x86_64_fb_fallback_frame_state (struct _Unwind_Context *context,
+ _Unwind_FrameState *fs)
+{
+ unsigned int *pc = context->ra;
+ struct sigframe *sf;
+ long new_cfa;
+
+/* sys/amd64/amd64/sigtramp.S:
+
+ 48 8d 7c 24 10 lea 0x10(%rsp),%rdi
+ 6a 00 pushq $0x0
+ 48 c7 c0 a1 01 00 00 mov $0x1a1,%rax
+ 0f 05 syscall
+*/
+
+ if ( (pc[0] == 0x247c8d48U)
+ && (pc[1] == 0x48006a10U)
+ && (pc[2] == 0x01a1c0c7U)
+ && (pc[3] == 0x050f0000U))
+ {
+ sf = (struct sigframe *) context->cfa;
+ }
+ else
+ return _URC_END_OF_STACK;
+
+ new_cfa = sf->sf_uc.uc_mcontext.mc_rsp;
+ fs->regs.cfa_how = CFA_REG_OFFSET;
+ /* Register 7 is rsp */
+ fs->regs.cfa_reg = 7;
+ fs->regs.cfa_offset = new_cfa - (long) context->cfa;
+
+ /* The SVR4 register numbering macros aren't usable in libgcc. */
+ fs->regs.reg[0].how = REG_SAVED_OFFSET;
+ fs->regs.reg[0].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rax - new_cfa;
+ fs->regs.reg[1].how = REG_SAVED_OFFSET;
+ fs->regs.reg[1].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rdx - new_cfa;
+ fs->regs.reg[2].how = REG_SAVED_OFFSET;
+ fs->regs.reg[2].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rcx - new_cfa;
+ fs->regs.reg[3].how = REG_SAVED_OFFSET;
+ fs->regs.reg[3].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rbx - new_cfa;
+ fs->regs.reg[4].how = REG_SAVED_OFFSET;
+ fs->regs.reg[4].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rsi - new_cfa;
+ fs->regs.reg[5].how = REG_SAVED_OFFSET;
+ fs->regs.reg[5].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rdi - new_cfa;
+ fs->regs.reg[6].how = REG_SAVED_OFFSET;
+ fs->regs.reg[6].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rbp - new_cfa;
+ fs->regs.reg[8].how = REG_SAVED_OFFSET;
+ fs->regs.reg[8].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r8 - new_cfa;
+ fs->regs.reg[9].how = REG_SAVED_OFFSET;
+ fs->regs.reg[9].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r9 - new_cfa;
+ fs->regs.reg[10].how = REG_SAVED_OFFSET;
+ fs->regs.reg[10].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r10 - new_cfa;
+ fs->regs.reg[11].how = REG_SAVED_OFFSET;
+ fs->regs.reg[11].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r11 - new_cfa;
+ fs->regs.reg[12].how = REG_SAVED_OFFSET;
+ fs->regs.reg[12].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r12 - new_cfa;
+ fs->regs.reg[13].how = REG_SAVED_OFFSET;
+ fs->regs.reg[13].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r13 - new_cfa;
+ fs->regs.reg[14].how = REG_SAVED_OFFSET;
+ fs->regs.reg[14].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r14 - new_cfa;
+ fs->regs.reg[15].how = REG_SAVED_OFFSET;
+ fs->regs.reg[15].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_r15 - new_cfa;
+ fs->regs.reg[16].how = REG_SAVED_OFFSET;
+ fs->regs.reg[16].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_rip - new_cfa;
+ fs->retaddr_column = 16;
+ fs->signal_frame = 1;
+ return _URC_NO_REASON;
+}
+
+#else /* ifdef __x86_64__ */
+
+#define MD_FALLBACK_FRAME_STATE_FOR x86_fb_fallback_frame_state
+
+static _Unwind_Reason_Code
+x86_fb_fallback_frame_state (struct _Unwind_Context *context,
+ _Unwind_FrameState *fs)
+{
+ unsigned int *pc = context->ra;
+ struct sigframe *sf;
+ long new_cfa;
+
+/* sys/amd64/ia32/ia32_sigtramp.S
+
+ 8d 44 24 20 lea 0x20(%esp),%eax
+ 50 push %eax
+ b8 a1 01 00 00 mov $0x1a1,%eax
+ 50 push %eax
+ cd 80 int $0x80
+ eb fe jmp -
+*/
+
+/* sys/i386/i386/locore.s: sigcode()
+
+ 8d 44 24 20 lea 0x20(%esp),%eax
+ 50 push %eax
+ f7 40 54 00 00 02 00 testl $0x20000,0x54(%eax)
+ 75 03 jne +
+ 8e 68 14 mov 0x14(%eax),%gs
+ b8 a1 01 00 00 mov $0x1a1,%eax
+ 50 push %eax
+ cd 80 int $0x80
+ eb fe jmp -
+*/
+
+ if ((pc[0] == 0x2024448dU)
+ && ((
+ (pc[1] == 0x01a1b850U)
+ && (pc[2] == 0xcd500000U)
+ && ((pc[3] & 0xFF) == 0x80)
+ )
+
+ || (
+ (pc[4] == 0x01a1b814U)
+ && (pc[5] == 0xcd500000U)
+ && ((pc[6] & 0xFF) == 0x80)
+ )))
+ {
+ sf = (struct sigframe *) context->cfa;
+ }
+ else
+ return _URC_END_OF_STACK;
+
+ new_cfa = sf->sf_uc.uc_mcontext.mc_esp;
+ fs->regs.cfa_how = CFA_REG_OFFSET;
+ fs->regs.cfa_reg = 4;
+ fs->regs.cfa_offset = new_cfa - (long) context->cfa;
+
+ /* The SVR4 register numbering macros aren't usable in libgcc. */
+ fs->regs.reg[0].how = REG_SAVED_OFFSET;
+ fs->regs.reg[0].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_eax - new_cfa;
+ fs->regs.reg[3].how = REG_SAVED_OFFSET;
+ fs->regs.reg[3].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_ebx - new_cfa;
+ fs->regs.reg[1].how = REG_SAVED_OFFSET;
+ fs->regs.reg[1].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_ecx - new_cfa;
+ fs->regs.reg[2].how = REG_SAVED_OFFSET;
+ fs->regs.reg[2].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_edx - new_cfa;
+ fs->regs.reg[6].how = REG_SAVED_OFFSET;
+ fs->regs.reg[6].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_esi - new_cfa;
+ fs->regs.reg[7].how = REG_SAVED_OFFSET;
+ fs->regs.reg[7].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_edi - new_cfa;
+ fs->regs.reg[5].how = REG_SAVED_OFFSET;
+ fs->regs.reg[5].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_ebp - new_cfa;
+ fs->regs.reg[8].how = REG_SAVED_OFFSET;
+ fs->regs.reg[8].loc.offset = (long)&sf->sf_uc.uc_mcontext.mc_eip - new_cfa;
+ fs->retaddr_column = 8;
+ fs->signal_frame = 1;
+ return _URC_NO_REASON;
+}
+
+#endif /* ifdef __x86_64__ */
+#endif /* ifdef inhibit_libc */
