[PATCH v3 3/3] btrace, vdso: add vdso target sections

[Markus Metzger <markus dot t dot metzger at intel dot com>]

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.

2014-05-21  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                 | 18 +++++++++++++
 gdb/testsuite/gdb.btrace/vdso.c   | 30 ++++++++++++++++++++++
 gdb/testsuite/gdb.btrace/vdso.exp | 53 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 101 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..b29421e 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 +132,23 @@ 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;
+
+  if (build_section_table (nbfd, &sections, &sections_end) == 0)
+    {
+      make_cleanup (xfree, sections);
+
+      /* 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..34a5bf0
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/vdso.exp
@@ -0,0 +1,53 @@
+# 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.*"
+
+with_test_prefix "replay" {
+	# 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