freebsd-unwind.h: New file.

2017-03-10  John Marino  <gnugcc@marino.st>

    * config/aarch64/freebsd-unwind.h: New file.
    * config.host: Add aarch64-*-freebsd unwinder.

From-SVN: r246052

libgcc/ChangeLog

+2017-03-10  John Marino  <gnugcc@marino.st>
+
+	* config/aarch64/freebsd-unwind.h: New file.
+	* config.host: Add aarch64-*-freebsd unwinder.
+
 2017-03-10  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	* config/rs6000/crtrestvr.s: Use .machine altivec.

libgcc/config.host

@@ -340,7 +340,7 @@ aarch64*-*-freebsd*)
 	extra_parts="$extra_parts crtfastmath.o"
 	tmake_file="${tmake_file} ${cpu_type}/t-aarch64"
 	tmake_file="${tmake_file} ${cpu_type}/t-softfp t-softfp t-crtfm"
-	md_unwind_header=aarch64/aarch64-unwind.h
+	md_unwind_header=aarch64/freebsd-unwind.h
 	;;
 aarch64*-*-linux*)
 	extra_parts="$extra_parts crtfastmath.o"

libgcc/config/aarch64/freebsd-unwind.h

+/* DWARF2 EH unwinding support for FreeBSD/ARM64 (aarch64).
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   Contributed by John Marino <gnugcc@marino.st>
+
+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/>.  */
+
+/* Identify a signal frame, and set the frame state data appropriately.
+   See unwind-dw2.c for the structs. */
+
+/* Always include AArch64 unwinder header file.  */
+#include "config/aarch64/aarch64-unwind.h"
+
+#include <sys/types.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/ucontext.h>
+#include <machine/frame.h>
+#include <sys/user.h>
+#include <sys/sysctl.h>
+
+#define REG_NAME(reg)   mc_gpregs.gp_## reg
+#define XREG(num)       mc_gpregs.gp_x[num]
+#define DARC            __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__
+
+#define MD_FALLBACK_FRAME_STATE_FOR aarch64_freebsd_fallback_frame_state
+
+static int
+aarch64_outside_sigtramp_range (unsigned char *pc)
+{
+  static int sigtramp_range_determined = 0;
+  static unsigned char *sigtramp_start, *sigtramp_end;
+
+  if (sigtramp_range_determined == 0)
+    {
+      struct kinfo_sigtramp kst = {0};
+      size_t len = sizeof (kst);
+      int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP, getpid() };
+
+      sigtramp_range_determined = 1;
+      if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
+      {
+        sigtramp_range_determined = 2;
+        sigtramp_start = kst.ksigtramp_start;
+        sigtramp_end   = kst.ksigtramp_end;
+      }
+    }
+  if (sigtramp_range_determined < 2)  /* sysctl failed if < 2 */
+    return 1;
+
+  return (pc < sigtramp_start || pc >= sigtramp_end);
+}
+
+static _Unwind_Reason_Code
+aarch64_freebsd_fallback_frame_state
+(struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+  int n;
+  struct sigframe *sf;
+  mcontext_t *sc;
+  _Unwind_Ptr new_cfa;
+
+  if (aarch64_outside_sigtramp_range(context->ra))
+    return _URC_END_OF_STACK;
+
+  sf = (struct sigframe *) context->cfa;
+  sc = &sf->sf_uc.uc_mcontext;
+
+  new_cfa = (_Unwind_Ptr) sc;
+  fs->regs.cfa_how = CFA_REG_OFFSET;
+  fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
+  fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
+
+  for (n = 0; n < 32; n++)
+    fs->regs.reg[n].how = REG_SAVED_OFFSET;
+
+  for (n = 0; n < 30; n++)
+    fs->regs.reg[n].loc.offset = (_Unwind_Ptr) &(sc->XREG(n)) - new_cfa;
+
+  fs->regs.reg[30].loc.offset = (_Unwind_Ptr) &(sc->REG_NAME(lr)) - new_cfa;
+  fs->regs.reg[31].loc.offset = (_Unwind_Ptr) &(sc->REG_NAME(sp)) - new_cfa;
+
+  fs->regs.reg[DARC].how = REG_SAVED_OFFSET;
+  fs->regs.reg[DARC].loc.offset = (_Unwind_Ptr) &(sc->REG_NAME(elr)) - new_cfa;
+
+  fs->retaddr_column = DARC;
+  fs->signal_frame = 1;
+
+  return _URC_NO_REASON;
+}