Fix failure to find member of a typedef base class

The test case below demonstrates the problem, as described in this PR's Comment 5:

typedef struct {
        int x;
} A;

struct C : A {
        int y;
};

int main()
{
        C c;
        return 55;
}

$ gdb a.out
(gdb) ptype C::x
Internal error: non-aggregate type to value_struct_elt_for_reference

In value_struct_elt_for_reference(), need to call check_typedef() on
the aggregate type to handle the case of *curtype being ptr->typedef.

Tested on x86_64-linux. No regressions.

gdb/ChangeLog

@@ -970,6 +970,12 @@
 	* symfile.c (addr_info_make_relative): Likewise.
 	* thread.c (value_in_thread_stack_temporaries): Likewise.
 
+2018-06-12  Weimin Pan  <weimin.pan@oracle.com>
+
+	PR gdb/16841
+	* valops.c (value_struct_elt_for_reference): Call check_typedef on
+	aggregate type to get its real type before accessing it.
+
 2018-05-29  Weimin Pan  <weimin.pan@oracle.com>
 
 	* minsyms.h (lookup_minimal_symbol_and_objfile): Remove declaration.

gdb/testsuite/ChangeLog

@@ -1,3 +1,4 @@
+<<<<<<< HEAD
 2018-06-18  Tom de Vries  <tdevries@suse.de>
 
 	* gdb.ada/bp_inlined_func.exp: Allow 5 breakpoint locations.
@@ -95,6 +96,13 @@
 
 	* gdb.base/endian.exp: New test.
 	* gdb.base/endian.c: New test source.
+=======
+2018-06-12  Weimin Pan  <weimin.pan@oracle.com>
+
+	PR gdb/16841
+	* gdb.cp/typedef-base.cc: New file.
+	* gdb.cp/typedef-base.exp: New file.
+>>>>>>> Fix failure to find member of a typedef base class
 
 2018-05-24  Andrew Burgess  <andrew.burgess@embecosm.com>
 

gdb/testsuite/gdb.cp/typedef-base.cc

@@ -0,0 +1,30 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2018 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/>.  */
+
+typedef struct {
+  int x;
+} A;
+
+struct C : A {
+  int y;
+};
+
+int main()
+{
+  C c;
+  return 55;
+}

gdb/testsuite/gdb.cp/typedef-base.exp

@@ -0,0 +1,39 @@
+# Copyright 2018 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/>.
+#
+# Make sure that inheritance through a typedef is well handled.
+
+if { [skip_cplus_tests] } { continue }
+
+standard_testfile .cc
+
+if [get_compiler_info "c++"] {
+    return -1
+}
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug c++}]} {
+    return -1
+}
+
+clean_restart $testfile
+
+if ![runto_main] {
+    untested "could not run to main"
+    return -1
+}
+
+gdb_test "ptype C::x" \
+         "type = int" \
+         "ptype typedef base struct member"

gdb/valops.c

@@ -3343,7 +3343,7 @@ value_struct_elt_for_reference (struct type *domain, int offset,
 				int want_address,
 				enum noside noside)
 {
-  struct type *t = curtype;
+  struct type *t = check_typedef (curtype);
   int i;
   struct value *v, *result;