Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/backends/aarch64_unwind.c b/backends/aarch64_unwind.c
new file mode 100644
index 0000000..e0a7e96
--- /dev/null
+++ b/backends/aarch64_unwind.c
@@ -0,0 +1,83 @@
+/* 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
+
+#define BACKEND aarch64_
+#define FP_REG 29
+#define LR_REG 30
+#define SP_REG 31
+#define FP_OFFSET 0
+#define LR_OFFSET 8
+#define SP_OFFSET 16
+
+#include "libebl_CPU.h"
+
+/* There was no CFI. Maybe we happen to have a frame pointer and can unwind from that? */
+
+bool
+EBLHOOK(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 __attribute__ ((unused)))
+{
+ Dwarf_Word fp, lr, sp;
+
+ if (!getfunc(LR_REG, 1, &lr, arg))
+ return false;
+
+ if (lr == 0 || !setfunc(-1, 1, &lr, arg))
+ return false;
+
+ if (!getfunc(FP_REG, 1, &fp, arg))
+ fp = 0;
+
+ if (!getfunc(SP_REG, 1, &sp, arg))
+ sp = 0;
+
+ Dwarf_Word newLr, newFp, newSp;
+
+ if (!readfunc(fp + LR_OFFSET, &newLr, arg))
+ newLr = 0;
+
+ if (!readfunc(fp + FP_OFFSET, &newFp, arg))
+ newFp = 0;
+
+ newSp = fp + SP_OFFSET;
+
+ // These are not fatal if they don't work. They will just prevent unwinding at the next frame.
+ setfunc(LR_REG, 1, &newLr, arg);
+ setfunc(FP_REG, 1, &newFp, arg);
+ setfunc(SP_REG, 1, &newSp, arg);
+
+ // If the fp is invalid, we might still have a valid lr.
+ // But if the fp is valid, then the stack should be moving in the right direction.
+ return fp == 0 || newSp > sp;
+}