PATCH: Fix for PR9631

[Pedro Alves <pedro@codesourcery.com>]

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PR9631 shows a case where vbasetype can be a TYPE_STUB, and since we were
not accounting for it, we crashed in TYPE_FIELD_BITPOS:

static int
gnuv3_baseclass_offset (struct type *type, int index, const bfd_byte *valaddr,
			CORE_ADDR address)
{
...
  vbasetype = TYPE_VPTR_BASETYPE (type);
  vbasetype_vptr_fieldno = get_vptr_fieldno (vbasetype, NULL);

  if (vbasetype_vptr_fieldno >= 0
      && TYPE_FIELD_BITPOS (vbasetype, vbasetype_vptr_fieldno) != 0) <<< here
    error (_("Illegal vptr offset in class %s"),
	   TYPE_NAME (vbasetype) ? TYPE_NAME (vbasetype) : "<unknown>");

This patch handles it, and adds new testcase.  Does it look like the
right thing to do here?  get_vptr_fieldno also always goes through
check_typedef right at the top.

OK?

-- 
Pedro Alves

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2009-01-22  Pedro Alves  <pedro@codesourcery.com>

	PR c++/9631:
	* gnu-v3-abi.c (gnuv3_baseclass_offset): Call check_typedef on
	vbasetype.

2009-01-22  Pedro Alves  <pedro@codesourcery.com>

	PR c++/9631:
	* gdb.cp/pr9631.cc, gdb.cp/pr9631.exp: New.

---
 gdb/gnu-v3-abi.c                |    2 -
 gdb/testsuite/gdb.cp/pr9631.cc  |   42 +++++++++++++++++++++++++++++++++++
 gdb/testsuite/gdb.cp/pr9631.exp |   48 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)

Index: src/gdb/gnu-v3-abi.c
===================================================================
--- src.orig/gdb/gnu-v3-abi.c	2009-01-21 12:51:12.000000000 +0000
+++ src/gdb/gnu-v3-abi.c	2009-01-22 15:21:03.000000000 +0000
@@ -460,7 +460,7 @@ gnuv3_baseclass_offset (struct type *typ
      start of whichever baseclass it resides in, as a sanity measure - iff
      we have debugging information for that baseclass.  */
 
-  vbasetype = TYPE_VPTR_BASETYPE (type);
+  vbasetype = check_typedef (TYPE_VPTR_BASETYPE (type));
   vbasetype_vptr_fieldno = get_vptr_fieldno (vbasetype, NULL);
 
   if (vbasetype_vptr_fieldno >= 0
Index: src/gdb/testsuite/gdb.cp/pr9631.cc
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ src/gdb/testsuite/gdb.cp/pr9631.cc	2009-01-22 16:12:55.000000000 +0000
@@ -0,0 +1,42 @@
+/* This test script is part of GDB, the GNU debugger.
+
+   Copyright 2009,
+   Free Software Foundation, Inc.
+
+   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/>.
+*/
+
+namespace foo
+{
+  class vbase
+  {
+  public:
+    virtual ~vbase() {}
+  };
+};
+
+class empty_base
+{
+};
+
+class bar : public foo::vbase, public virtual empty_base
+{
+};
+
+int
+main(int argc, char *argv[])
+{
+  bar tender;
+  return 0; /* set breakpoint here */
+}
Index: src/gdb/testsuite/gdb.cp/pr9631.exp
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ src/gdb/testsuite/gdb.cp/pr9631.exp	2009-01-22 16:12:09.000000000 +0000
@@ -0,0 +1,48 @@
+# Copyright 2009 Free Software Foundation, Inc.
+
+# 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/>.
+
+# This file is part of the gdb testsuite.
+
+if { [skip_cplus_tests] } { continue }
+
+set testfile "pr9631"
+set srcfile ${testfile}.cc
+set binfile ${objdir}/${subdir}/${testfile}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug c++}] != "" } {
+     untested pr9631.exp
+     return -1
+}
+
+if [get_compiler_info ${binfile} "c++"] {
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+if ![runto_main] then {
+    perror "couldn't run to breakpoint"
+    continue
+}
+
+gdb_breakpoint [gdb_get_line_number "set breakpoint here"]
+gdb_continue_to_breakpoint "after bar tender is initialized"
+
+gdb_test \
+  "print tender" \
+  "\\\$1 = {<foo::vbase> = {_vptr.vbase = $hex}, <empty_base> = {<No data fields>}, <No data fields>}"