[Libunwind-devel] [PATCH 4/4] Add test of backtracing using ARM-specific tables

[Ken Werner]

From: Zachary T Welch <address@hidden>

Uses .ARM.exidx and .ARM.extbl sections to produce a backtrace.

Signed-off-by: Ken Werner <address@hidden>
---
 .gitignore             |    1 +
 tests/Makefile.am      |   11 ++++++
 tests/arm-extbl-test.c |   95 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 107 insertions(+), 0 deletions(-)
 create mode 100644 tests/arm-extbl-test.c

diff --git a/.gitignore b/.gitignore
index d3ed395..ddf9372 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,3 +50,4 @@ tests/test-strerror
 tests/test-proc-info
 tests/test-ptrace-misc
 tests/test-varargs
+tests/arm-extbl-test
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 4d86445..5b50529 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -46,6 +46,9 @@ endif #ARCH_IA64
                        Ltest-nomalloc rs-race
  noinst_PROGRAMS_cdep = forker mapper test-ptrace-misc test-varargs    \
                        Gperf-simple Lperf-simple
+if ARCH_ARM
+ check_PROGRAMS_arch = arm-extbl-test
+endif #ARCH_ARM
 
 if SUPPORT_CXX_EXCEPTIONS
  check_PROGRAMS_cdep += Ltest-cxx-exceptions
@@ -72,6 +75,11 @@ TESTS = $(check_PROGRAMS) $(check_SCRIPTS)
 noinst_PROGRAMS = $(noinst_PROGRAMS_common) $(noinst_PROGRAMS_cdep) \
        $(noinst_PROGRAMS_arch)
 
+arm_extbl_test_CPPFLAGS = -I$(top_srcdir)/src \
+                               -I$(top_srcdir)/include/tdep-$(arch) \
+                               -funwind-tables
+arm_extbl_test_LDFLAGS = -static
+
 Lia64_test_readonly_SOURCES = Lia64-test-readonly.c ia64-test-readonly-asm.S
 Gia64_test_readonly_SOURCES = Gia64-test-readonly.c ia64-test-readonly-asm.S
 Lia64_test_stack_SOURCES = Lia64-test-stack.c ia64-test-stack-asm.S \
@@ -85,6 +93,7 @@ Gia64_test_nat_SOURCES = Gia64-test-nat.c ia64-test-nat-asm.S
 ia64_test_dyn1_SOURCES = ia64-test-dyn1.c ia64-dyn-asm.S flush-cache.S
 ppc64_test_altivec_SOURCES = ppc64-test-altivec.c  ppc64-test-altivec-utils.c
 ppc64_test_wchar_SOURCES = ppc64-test-wchar.c
+arm_extbl_test_SOURCES = arm-extbl-test.c
 Gtest_init_SOURCES = Gtest-init.cxx
 Ltest_init_SOURCES = Ltest-init.cxx
 Ltest_cxx_exceptions_SOURCES = Ltest-cxx-exceptions.cxx
@@ -133,3 +142,5 @@ Lperf_simple_LDADD = $(LIBUNWIND_local)
 
 test_setjmp_LDADD = $(LIBUNWIND_setjmp)
 ia64_test_setjmp_LDADD = $(LIBUNWIND_setjmp)
+
+arm_extbl_test_LDADD = $(top_builddir)/src/libunwind-elf32.la $(LIBUNWIND)
diff --git a/tests/arm-extbl-test.c b/tests/arm-extbl-test.c
new file mode 100644
index 0000000..752f59f
--- /dev/null
+++ b/tests/arm-extbl-test.c
@@ -0,0 +1,95 @@
+/* libunwind - a platform-independent unwind library
+   Copyright 2011 Linaro Limited
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+  
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include "libunwind_i.h"
+
+static int
+arm_exidx_unwind_frame (struct arm_stackframe *frame)
+{
+  Debug (2, "frame: fp=%p, sp=%p, lr=%p, pc=%p\n",
+      frame->fp, frame->sp, frame->lr, frame->pc);
+
+  struct arm_exidx_table *table = arm_exidx_table_find (frame->pc);
+  if (NULL == table)
+    return -1;
+
+  struct arm_exidx_entry *entry = arm_exidx_table_lookup (table, frame->pc);
+  if (NULL == entry)
+    return -1;
+
+  struct arm_exidx_vrs s;
+  arm_exidx_frame_to_vrs(frame, &s);
+
+  uint8_t buf[32], n_buf = arm_exidx_extract (entry, buf);
+  if (arm_exidx_decode (buf, n_buf, &arm_exidx_vrs_callback, &s) < 0)
+    return -1;
+
+  return arm_exidx_vrs_to_frame(&s, frame);
+}
+
+typedef void (*arm_exidx_backtrace_callback_t) (void *, struct arm_stackframe 
*);
+
+static int
+arm_exidx_backtrace (arm_exidx_backtrace_callback_t cb)
+{
+  register void *current_sp asm ("sp");
+  struct arm_stackframe frame = {
+    .fp = __builtin_frame_address (0),
+    .sp = current_sp,
+    .lr = __builtin_return_address (0),
+    .pc = &arm_exidx_backtrace,
+  };
+
+  while (1)
+    {
+      void *where = frame.pc;
+      if (arm_exidx_unwind_frame (&frame) < 0)
+       break;
+      (*cb) (where, &frame);
+    }
+  return 0;
+}
+
+static void
+b (void *where, struct arm_stackframe *frame)
+{
+  Debug (2, "%p -> %p (%p)\n", where, frame->pc, frame->sp - 4);
+}
+
+static int
+a (int foo)
+{
+  if (foo > 0)
+    return a (foo - 1);
+  arm_exidx_backtrace (&b);
+  return foo;
+}
+
+int
+main (int argc, char *argv[])
+{
+  mi_init ();
+  arm_exidx_init_local (argv[0]);
+  return a (argc);
+}
-- 
1.7.4.1