Add frame pointer unwinding for aarch64

Change-Id: I43f184deba97ed57cc7efbfbda9432cfd8d99664
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>

3 files changed, 81 insertions, 1 deletions

diff --git a/3rdparty/elfutils/backends/aarch64/aarch64.pro b/3rdparty/elfutils/backends/aarch64/aarch64.pro
index 5489b1d..a53be98 100644
--- a/3rdparty/elfutils/backends/aarch64/aarch64.pro
+++ b/3rdparty/elfutils/backends/aarch64/aarch64.pro
@@ -8,7 +8,8 @@ SOURCES += \
     ../aarch64_initreg.c \
     ../aarch64_regs.c \
     ../aarch64_retval.c \
-    ../aarch64_symbol.c
+    ../aarch64_symbol.c \
+    ../aarch64_unwind.c
 
 HEADERS += \
     ../aarch64_reloc.def
diff --git a/3rdparty/elfutils/backends/aarch64_init.c b/3rdparty/elfutils/backends/aarch64_init.c
index b0fd17a..8a96f73 100644
--- a/3rdparty/elfutils/backends/aarch64_init.c
+++ b/3rdparty/elfutils/backends/aarch64_init.c
@@ -64,6 +64,7 @@ aarch64_init (elf, machine, eh, ehlen)
      + ALT_FRAME_RETURN_COLUMN (used when LR isn't used) = 97 DWARF regs. */
   eh->frame_nregs = 97;
   HOOK (eh, set_initial_registers_tid);
+  HOOK (eh, unwind);
 
   return MODVERSION;
 }
diff --git a/3rdparty/elfutils/backends/aarch64_unwind.c b/3rdparty/elfutils/backends/aarch64_unwind.c
new file mode 100644
index 0000000..5560c58
--- /dev/null
+++ b/3rdparty/elfutils/backends/aarch64_unwind.c
@@ -0,0 +1,78 @@
+/* Get previous frame state for an existing frame state.
+   Copyright (C) 2016 The Qt Company Ltd.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils 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.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdlib.h>
+#include <assert.h>
+
+#define BACKEND aarch64_
+#include "libebl_CPU.h"
+#include <stdio.h>
+
+/* There was no CFI. Maybe we happen to have a frame pointer and can unwind from that?  */
+
+bool
+aarch64_unwind (Ebl *ebl __attribute__ ((unused)), Dwarf_Addr pc __attribute__ ((unused)),
+         ebl_tid_registers_t *setfunc, ebl_tid_registers_get_t *getfunc,
+         ebl_pid_memory_read_t *readfunc, void *arg, bool *signal_framep)
+{
+  const int fpReg = 29;
+  const int lrReg = 30;
+  const int spReg = 31;
+
+  Dwarf_Word fp;
+  if (!getfunc(fpReg, 1, &fp, arg) || fp == 0)
+      return false;
+
+  Dwarf_Word lr;
+  if (!getfunc(lrReg, 1, &lr, arg))
+      return false;
+
+  Dwarf_Word newFp, newLr;
+  if (!readfunc(fp, &newFp, arg))
+      return false;
+  fp += 8;
+  if (!readfunc(fp, &newLr, arg))
+      return false;
+
+  fp += 8;
+  if (!setfunc(spReg, 1, &fp, arg))
+      return false;
+  if (!setfunc(fpReg, 1, &newFp, arg))
+      return false;
+  if (!setfunc(-1, 1, &newLr, arg))
+      return false;
+  if (!setfunc(lrReg, 1, &newLr, arg))
+      return false;
+
+  *signal_framep = false;
+  return true;
+}