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[PATCH 4/5] Add i386 frame pointer unwinder.
Add a simple i386_unwind.c frame pointer unwinder as fallback if DWARF/CFI
unwinding fails.
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
backends/ChangeLog | 6 +++
backends/Makefile.am | 2 +-
backends/i386_init.c | 3 +-
backends/i386_unwind.c | 84 ++++++++++++++++++++++++++++++++++++
tests/ChangeLog | 9 ++++
tests/Makefile.am | 5 ++-
tests/backtrace.i386.fp.core.bz2 | Bin 0 -> 8532 bytes
tests/backtrace.i386.fp.exec.bz2 | Bin 0 -> 357436 bytes
tests/run-backtrace-fp-core-i386.sh | 29 +++++++++++++
9 files changed, 135 insertions(+), 3 deletions(-)
create mode 100644 backends/i386_unwind.c
create mode 100644 tests/backtrace.i386.fp.core.bz2
create mode 100755 tests/backtrace.i386.fp.exec.bz2
create mode 100755 tests/run-backtrace-fp-core-i386.sh
diff --git a/backends/ChangeLog b/backends/ChangeLog
index eec9923..733e72c 100644
--- a/backends/ChangeLog
+++ b/backends/ChangeLog
@@ -1,3 +1,9 @@
+2017-04-06 Mark Wielaard <mark@klomp.org>
+
+ * i386_unwind.c: New file.
+ * i386_init.c: Hook i386_unwind.
+ * Makefile.am (i386_SRCS): Add i386_unwind.c
+
2017-02-09 Ulf Hermann <ulf.hermann@qt.io>
* x86_64_unwind.c: New file
diff --git a/backends/Makefile.am b/backends/Makefile.am
index 60917b9..22eb6ac 100644
--- a/backends/Makefile.am
+++ b/backends/Makefile.am
@@ -48,7 +48,7 @@ libdw = ../libdw/libdw.so
i386_SRCS = i386_init.c i386_symbol.c i386_corenote.c i386_cfi.c \
i386_retval.c i386_regs.c i386_auxv.c i386_syscall.c \
- i386_initreg.c
+ i386_initreg.c i386_unwind.c
cpu_i386 = ../libcpu/libcpu_i386.a
libebl_i386_pic_a_SOURCES = $(i386_SRCS)
am_libebl_i386_pic_a_OBJECTS = $(i386_SRCS:.c=.os)
diff --git a/backends/i386_init.c b/backends/i386_init.c
index 515d5ac..fc1587a 100644
--- a/backends/i386_init.c
+++ b/backends/i386_init.c
@@ -1,5 +1,5 @@
/* Initialization of i386 specific backend library.
- Copyright (C) 2000-2009, 2013 Red Hat, Inc.
+ Copyright (C) 2000-2009, 2013, 2017 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <drepper@redhat.com>, 2000.
@@ -65,6 +65,7 @@ i386_init (Elf *elf __attribute__ ((unused)),
/* gcc/config/ #define DWARF_FRAME_REGISTERS. For i386 it is 17, why? */
eh->frame_nregs = 9;
HOOK (eh, set_initial_registers_tid);
+ HOOK (eh, unwind);
return MODVERSION;
}
diff --git a/backends/i386_unwind.c b/backends/i386_unwind.c
new file mode 100644
index 0000000..5c9a5de
--- /dev/null
+++ b/backends/i386_unwind.c
@@ -0,0 +1,84 @@
+/* Get previous frame state for an existing frame state using frame pointers.
+ Copyright (C) 2017 Red Hat, Inc.
+ 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 i386_
+#include "libebl_CPU.h"
+
+/* Register numbers for frame and stack pointers. We take advantage of
+ them being next to each other when calling getfunc and setfunc. */
+#define ESP 4
+#define EBP (ESP + 1)
+
+/* Most basic frame pointer chasing with EBP as frame pointer.
+ PC = *(FP + 4), SP = FP + 8, FP = *FP. */
+bool
+i386_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)))
+{
+ /* sp = 0, fp = 1 */
+ Dwarf_Word regs[2];
+
+ /* Get current stack and frame pointers. */
+ if (! getfunc (ESP, 2, regs, arg))
+ return false;
+
+ Dwarf_Word sp = regs[0];
+ Dwarf_Word fp = regs[1];
+
+ /* Sanity check. We only support traditional stack frames. */
+ if (fp == 0 || sp == 0 || fp < sp)
+ return false;
+
+ /* Get the return address from the stack, it is our new pc. */
+ Dwarf_Word ret_addr;
+ if (! readfunc (fp + 4, &ret_addr, arg) || ret_addr == 0)
+ return false;
+
+ /* Get new sp and fp. Sanity check again. */
+ sp = fp + 8;
+ if (! readfunc (fp, &fp, arg) || fp == 0 || sp >= fp)
+ return false;
+
+ /* Set new sp, fp and pc. */
+ regs[0] = sp;
+ regs[1] = fp;
+ if (! setfunc (ESP, 2, regs, arg) || ! setfunc (-1, 1, &ret_addr, arg))
+ return false;
+
+ return true;
+}
diff --git a/tests/ChangeLog b/tests/ChangeLog
index 49b6a3f..67a44f7 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,12 @@
+2017-04-06 Mark Wielaard <mark@klomp.org>
+
+ * run-backtrace-fp-core-i386.sh: New test.
+ * backtrace.i386.fp.core.bz2: New test file.
+ * backtrace.i386.fp.exec.bz2: New testfile.
+ * Makefile.am (TESTS): Add run-backtrace-fp-core-i386.sh.
+ (EXTRA_DIST): Add run-backtrace-fp-core-i386.sh,
+ backtrace.i386.fp.core.bz2 and backtrace.i386.fp.exec.bz2.
+
2017-02-09 Ulf Hermann <ulf.hermann@qt.io>
* Makefile.am: Add test for unwinding with frame pointers on x86_64
diff --git a/tests/Makefile.am b/tests/Makefile.am
index b0db19f..2c82bfd 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -117,7 +117,8 @@ TESTS = run-arextract.sh run-arsymtest.sh newfile test-nlist \
run-backtrace-native-core-biarch.sh run-backtrace-core-x86_64.sh \
run-backtrace-fp-core-x86_64.sh \
run-backtrace-core-x32.sh \
- run-backtrace-core-i386.sh run-backtrace-core-ppc.sh \
+ run-backtrace-core-i386.sh run-backtrace-fp-core-i386.sh \
+ run-backtrace-core-ppc.sh \
run-backtrace-core-s390x.sh run-backtrace-core-s390.sh \
run-backtrace-core-aarch64.sh run-backtrace-core-sparc.sh \
run-backtrace-demangle.sh run-stack-d-test.sh run-stack-i-test.sh \
@@ -297,6 +298,8 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh \
run-backtrace-fp-core-x86_64.sh \
run-backtrace-core-x32.sh \
backtrace-subr.sh backtrace.i386.core.bz2 backtrace.i386.exec.bz2 \
+ run-backtrace-fp-core-i386.sh \
+ backtrace.i386.fp.core.bz2 backtrace.i386.fp.exec.bz2 \
backtrace.x86_64.core.bz2 backtrace.x86_64.exec.bz2 \
backtrace.x86_64.fp.core.bz2 backtrace.x86_64.fp.exec.bz2 \
backtrace.ppc.core.bz2 backtrace.ppc.exec.bz2 \
diff --git a/tests/run-backtrace-fp-core-i386.sh b/tests/run-backtrace-fp-core-i386.sh
new file mode 100755
index 0000000..c58ff53
--- /dev/null
+++ b/tests/run-backtrace-fp-core-i386.sh
@@ -0,0 +1,29 @@
+#! /bin/bash
+# Copyright (C) 2017 Red Hat, Inc.
+# This file is part of elfutils.
+#
+# This file 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 of the License, or
+# (at your option) any later version.
+#
+# 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 a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+. $srcdir/backtrace-subr.sh
+
+# The binary is generated by compiling backtrace-child without unwind
+# information, but with -fno-omit-frame-pointer.
+#
+# gcc -static -O2 -fno-omit-frame-pointer -fno-asynchronous-unwind-tables \
+# -D_GNU_SOURCE -pthread -o tests/backtrace.i386.fp.exec -I. -Ilib \
+# tests/backtrace-child.c
+#
+# The core is generated by calling tests/backtrace.i386.fp.exec --gencore
+
+check_core i386.fp
--
1.8.3.1