[PATCH v2 3/3] btrace, vdso: add vdso target sections

Markus Metzger
2014-05-20T12:00:50Z

When loading symbols for the vdso, also add its sections to target_sections.

This fixes an issue with record btrace where vdso instructions could not be
disassembled during replay.

2014-05-20 Markus Metzger <markus.t.metzger@intel.com>

* symfile-mem.c (symbol_file_add_from_memory): Add BFD sections.

testsuite/
* gdb.btrace/vdso.c: New.
* gdb.btrace/vdso.exp: New.

---
gdb/symfile-mem.c | 17 +++++++++++++
gdb/testsuite/gdb.btrace/vdso.c | 30 +++++++++++++++++++++++
gdb/testsuite/gdb.btrace/vdso.exp | 51 +++++++++++++++++++++++++++++++++++++++
3 files changed, 98 insertions(+)
create mode 100644 gdb/testsuite/gdb.btrace/vdso.c
create mode 100644 gdb/testsuite/gdb.btrace/vdso.exp

diff --git a/gdb/symfile-mem.c b/gdb/symfile-mem.c
index 3f09c4d..19ae14a 100644
--- a/gdb/symfile-mem.c
+++ b/gdb/symfile-mem.c
@@ -92,6 +92,7 @@ symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr,
struct section_addr_info *sai;
unsigned int i;
struct cleanup *cleanup;
+ struct target_section *sections, *sections_end, *tsec;

if (bfd_get_flavour (templ) != bfd_target_elf_flavour)
error (_("add-symbol-file-from-memory not supported for this target"));
@@ -131,6 +132,22 @@ symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr,
from_tty ? SYMFILE_VERBOSE : 0,
sai, OBJF_SHARED, NULL);

+ sections = NULL;
+ sections_end = NULL;
+ make_cleanup (xfree, sections);
+
+ if (build_section_table (nbfd, &sections, &sections_end) == 0)
+ {
+ /* Adjust the target section addresses by the load address. */
+ for (tsec = sections; tsec != sections_end; ++tsec)
+ {
+ tsec->addr += loadbase;
+ tsec->endaddr += loadbase;
+ }
+
+ add_target_sections (&nbfd, sections, sections_end);
+ }
+
/* This might change our ideas about frames already looked at. */
reinit_frame_cache ();

diff --git a/gdb/testsuite/gdb.btrace/vdso.c b/gdb/testsuite/gdb.btrace/vdso.c
new file mode 100644
index 0000000..e16a3c6
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/vdso.c
@@ -0,0 +1,30 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2014 Free Software Foundation, Inc.
+
+ Contributed by Intel Corp. <markus.t.metzger@intel.com>
+
+ This program 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.
+
+ This program 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/>. */
+
+#include <sys/time.h>
+
+int
+main (void)
+{
+ struct timeval tv;
+
+ gettimeofday (&tv, 0); /* main.1. */
+
+ return 0; /* main.2. */
+}
diff --git a/gdb/testsuite/gdb.btrace/vdso.exp b/gdb/testsuite/gdb.btrace/vdso.exp
new file mode 100644
index 0000000..a84e198
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/vdso.exp
@@ -0,0 +1,51 @@
+# This testcase is part of GDB, the GNU debugger.
+#
+# Copyright 2014 Free Software Foundation, Inc.
+#
+# Contributed by Intel Corp. <markus.t.metzger@intel.com>
+#
+# This program 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.
+#
+# This program 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/>.
+#
+#
+# Test that we can access the vdso memory during replay for stepping.
+
+# check for btrace support
+if { [skip_btrace_tests] } { return -1 }
+
+# start inferior
+standard_testfile
+if [prepare_for_testing $testfile.exp $testfile $srcfile] {
+ return -1
+}
+if ![runto_main] {
+ return -1
+}
+
+# capture the disassembly of gettimeofday while live debugging
+set live_gettimeofday [capture_command_output "disassemble gettimeofday" ""]
+
+# trace the test code
+gdb_test_no_output "record btrace"
+gdb_test "next" "main\.2.*"
+
+# capture the disassembly of gettimeofday while replaying
+gdb_test "record goto begin" "main\.1.*"
+set replay_gettimeofday [capture_command_output "disassemble gettimeofday" ""]
+
+# the two disassemblys must be identical
+if ![string compare $live_gettimeofday $replay_gettimeofday] {
+ pass "disassemble gettimeofday"
+} else {
+ fail "disassemble gettimeofday"
+}
--
1.8.3.1