lang/gcc6-aux: Add unwind support to aarch64-freebsd

Together with a gcc devel patch to expmed.c to fix the two GNAT
internal compiler errors seen on the ACATS testsuite, the new signal
frame unwinder the remaining testsuite errors.  The Ada compiler on
aarch64-*-freebsd* is now perfect.

Unfortunately the revision bump causes an unnecessary rebuild on x86, but
that can't be avoid.

The unwind support will be pushed upstream to GCC.

2 files changed, 218 insertions, 2 deletions

diff --git a/lang/gcc6-aux/Makefile.version b/lang/gcc6-aux/Makefile.version
index ae28fb5217cc..909835b647a1 100644
--- a/lang/gcc6-aux/Makefile.version
+++ b/lang/gcc6-aux/Makefile.version
@@ -5,10 +5,10 @@ GCC_POINT=		3.1
 GCC_VERSION=		${GCC_BRANCH}.${GCC_POINT}
 SNAPSHOT=		20170202
 BUILD_RELEASE=		no
-MAIN_PR=		0
+MAIN_PR=		1
 UTIL_PR=		0
 ARMV7_PR=		1
-ARM64_PR=		1
+ARM64_PR=		2
 X86_PR=			1
 
 .if ${BUILD_RELEASE:Mno}
diff --git a/lang/gcc6-aux/files/diff-core b/lang/gcc6-aux/files/diff-core
index b8377742c92f..3e9126e94ad2 100644
--- a/lang/gcc6-aux/files/diff-core
+++ b/lang/gcc6-aux/files/diff-core
@@ -44,6 +44,114 @@
      %{static:-Bstatic}} \
 +  %{!static:--hash-style=gnu -rpath @PREFIX@/@GCCAUX@/lib} \
    %{symbolic:-Bsymbolic}"
+--- /dev/null
++++ libgcc/config/aarch64/freebsd-unwind.h
+@@ -0,0 +1,105 @@
++/* 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/>.  */
++
++/* Do code reading to identify a signal frame, and set the frame
++   state data appropriately.  See unwind-dw2.c for the structs. */
++
++#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;
++}
 --- gcc/Makefile.in.orig
 +++ gcc/Makefile.in
 @@ -1185,7 +1185,6 @@
@@ -105,3 +213,111 @@
  	  if [ ! -f gcc-cross$(exeext) ] \
  	      && [ "$(GCC_INSTALL_NAME)" != "$(GCC_TARGET_INSTALL_NAME)" ]; then \
  	    rm -f $(DESTDIR)$(bindir)/$(target_noncanonical)-gcc-tmp$(exeext); \
+--- gcc/expmed.c.orig
++++ gcc/expmed.c
+@@ -2286,11 +2286,13 @@
+    and AMOUNT the rtx for the amount to shift by.
+    Store the result in the rtx TARGET, if that is convenient.
+    If UNSIGNEDP is nonzero, do a logical shift; otherwise, arithmetic.
+-   Return the rtx for where the value is.  */
++   Return the rtx for where the value is.
++   If that cannot be done, abort the compilation unless MAY_FAIL is true,
++   in which case 0 is returned.  */
+ 
+ static rtx
+ expand_shift_1 (enum tree_code code, machine_mode mode, rtx shifted,
+-		rtx amount, rtx target, int unsignedp)
++		rtx amount, rtx target, int unsignedp, bool may_fail = false)
+ {
+   rtx op1, temp = 0;
+   int left = (code == LSHIFT_EXPR || code == LROTATE_EXPR);
+@@ -2487,7 +2489,7 @@
+ 	 define_expand for lshrsi3 was added to vax.md.  */
+     }
+ 
+-  gcc_assert (temp);
++  gcc_assert (temp != NULL_RTX || may_fail);
+   return temp;
+ }
+ 
+@@ -2506,6 +2508,16 @@
+ 			 shifted, GEN_INT (amount), target, unsignedp);
+ }
+ 
++/* Likewise, but return 0 if that cannot be done.  */
++
++static rtx
++maybe_expand_shift (enum tree_code code, machine_mode mode, rtx shifted,
++		    int amount, rtx target, int unsignedp)
++{
++  return expand_shift_1 (code, mode,
++			 shifted, GEN_INT (amount), target, unsignedp, true);
++}
++
+ /* Output a shift instruction for expression code CODE,
+    with SHIFTED being the rtx for the value to shift,
+    and AMOUNT the tree for the amount to shift by.
+@@ -5811,11 +5823,12 @@
+       if (rtx_equal_p (subtarget, op0))
+ 	subtarget = 0;
+ 
+-      tem = expand_shift (RSHIFT_EXPR, mode, op0,
+-			  GET_MODE_BITSIZE (mode) - 1,
+-			  subtarget, 0);
+-      tem = expand_binop (mode, sub_optab, tem, op0, subtarget, 0,
+-			  OPTAB_WIDEN);
++      tem = maybe_expand_shift (RSHIFT_EXPR, mode, op0,
++				GET_MODE_BITSIZE (mode) - 1,
++				subtarget, 0);
++      if (tem)
++	tem = expand_binop (mode, sub_optab, tem, op0, subtarget, 0,
++			    OPTAB_WIDEN);
+     }
+ 
+   if (code == EQ || code == NE)
+@@ -5877,9 +5890,9 @@
+     }
+ 
+   if (tem && normalizep)
+-    tem = expand_shift (RSHIFT_EXPR, mode, tem,
+-			GET_MODE_BITSIZE (mode) - 1,
+-			subtarget, normalizep == 1);
++    tem = maybe_expand_shift (RSHIFT_EXPR, mode, tem,
++			      GET_MODE_BITSIZE (mode) - 1,
++			      subtarget, normalizep == 1);
+ 
+   if (tem)
+     {
+--- libgcc/config.host.orig
++++ libgcc/config.host
+@@ -242,7 +242,8 @@
+   extra_parts="crtbegin.o crtbeginS.o crtend.o crtendS.o"
+   ;;
+ *-*-netbsd*)
+-  tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-slibgcc t-slibgcc-gld t-slibgcc-elf-ver"
++  tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-eh-dw2-dip"
++  tmake_file="$tmake_file t-slibgcc t-slibgcc-gld t-slibgcc-elf-ver"
+   # NetBSD 1.7 and later are set up to use GCC's crtstuff for
+   # ELF configurations.  We will clear extra_parts in the
+   # a.out configurations.
+@@ -337,6 +338,7 @@
+ 	extra_parts="$extra_parts crtfastmath.o"
+ 	tmake_file="${tmake_file} ${cpu_type}/t-aarch64"
+ 	tmake_file="${tmake_file} ${cpu_type}/t-softfp t-softfp t-crtfm"
++	md_unwind_header=aarch64/freebsd-unwind.h
+ 	;;
+ aarch64*-*-linux*)
+ 	extra_parts="$extra_parts crtfastmath.o"
+@@ -609,9 +611,12 @@
+ 	md_unwind_header=i386/freebsd-unwind.h
+ 	;;
+ i[34567]86-*-netbsdelf*)
++	tmake_file="${tmake_file} i386/t-crtstuff"
++	#md_unwind_header=i386/netbsd-unwind.h
+ 	;;
+ x86_64-*-netbsd*)
+ 	tmake_file="${tmake_file} i386/t-crtstuff"
++	#md_unwind_header=i386/netbsd-unwind.h
+ 	;;
+ i[34567]86-*-openbsd2.*|i[34567]86-*openbsd3.[0123])
+ 	;;