Add psymbols for nested types

c++/22968 involves the inability of ptype to find a type definition for
a type defined inside another type.  I recently added some additional
support for nested type definitions, but I apparently overlooked psymbols.

The user reports that using -readnow fixes the problem:

$ gdb 22968 -ex "ptype Outer::Inner"
There is no field named Inner

$ gdb -readnow 22968 -ex "ptype Outer::Inner"
type = struct Outer::Inner {
  <no data field>
}

We clearly did not find a psymbol for Outer::Inner because it was located
in another CU.  This patch addresses this problem by scanning structs
for additional psymbols.  Rust is already doing this.

With this patch, the identical result to "-readnow" is given (without
using `-readnow', of course).

gdb/ChangeLog:

	PR c++/22968
	* dwarf2read.c (scan_partial_symbols): Scan structs/classes for
	nested type definitions for C++, too.

gdb/testsuite/ChangeLog:

	PR c++/22968
	* gdb.cp/subtypes.exp: New file.
	* gdb.cp/subtypes.h: New file.
	* gdb.cp/subtypes.cc: New file.
	* gdb.cp/subtypes-2.cc: New file.

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2018-03-23  Keith Seitz  <keiths@redhat.com>
+
+	PR c++/22968
+	* dwarf2read.c (scan_partial_symbols): Scan structs/classes for
+	nested type definitions for C++, too.
+
 2018-03-23  Tom Tromey  <tom@tromey.com>
 
 	* machoread.c (struct oso_el): Add a constructor.  Don't define as

gdb/dwarf2read.c

@@ -9116,7 +9116,8 @@ scan_partial_symbols (struct partial_die_info *first_die, CORE_ADDR *lowpc,
 		{
 		  add_partial_symbol (pdi, cu);
 		}
-	      if (cu->language == language_rust && pdi->has_children)
+	      if ((cu->language == language_rust
+		   || cu->language == language_cplus) && pdi->has_children)
 		scan_partial_symbols (pdi->die_child, lowpc, highpc,
 				      set_addrmap, cu);
 	      break;

gdb/testsuite/ChangeLog

@@ -1,3 +1,11 @@
+2018-03-23  Keith Seitz  <keiths@redhat.com>
+
+	PR c++/22968
+	* gdb.cp/subtypes.exp: New file.
+	* gdb.cp/subtypes.h: New file.
+	* gdb.cp/subtypes.cc: New file.
+	* gdb.cp/subtypes-2.cc: New file.
+
 2018-03-23  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* gdb.arch/amd64-disp-step-avx.S: Add '_start' label.

gdb/testsuite/gdb.cp/subtypes-2.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/>.  */
+
+#include "subtypes.h"
+
+struct Outer::Inner
+{
+  int doit () { return 1; }
+  struct InnerInner {} p;
+  int a;
+};
+
+Outer::Outer (): p (new Inner), e (Oenum::OC)
+{
+  p->a = p->doit ();
+}

gdb/testsuite/gdb.cp/subtypes.cc

@@ -0,0 +1,42 @@
+/* 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/>.  */
+
+#include "subtypes.h"
+
+int
+main (int argc, char *argv[])
+{
+  struct Foo
+  {
+    int doit (void) { return 1111; }
+  } foo;
+
+  struct Bar
+  {
+    int doit (void) { return 2222; }
+  } bar;
+
+  struct Baz
+  {
+    int doit (void) { return 3333; }
+  } baz;
+  Outer o;
+  o.e = Outer::Oenum::OA;
+
+  return foo.doit () + bar.doit () + baz.doit () + foobar<int> (6)
+    + foobar<char> ('c');
+}

gdb/testsuite/gdb.cp/subtypes.exp

@@ -0,0 +1,52 @@
+# 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/>.
+
+# Test for subtype definitions, i.e., types defined in classes, functions,
+# etc.
+
+if {[skip_cplus_tests]} { continue }
+
+load_lib "cp-support.exp"
+
+standard_testfile .cc subtypes-2.cc
+
+if {[prepare_for_testing "failed to prepare" $testfile \
+	 [list $srcfile $srcfile2] {debug c++}]} {
+    return -1
+}
+
+gdb_test "ptype Outer::Inner::InnerInner" \
+    "type = struct Outer::Inner::InnerInner.*"
+gdb_test "ptype Outer::Inner" "type = struct Outer::Inner.*"
+gdb_test "ptype main::Foo" "type = struct Foo.*"
+gdb_test "ptype main::Bar" "type = struct Bar.*"
+gdb_test "ptype main::Baz" "type = struct Baz.*"
+gdb_test "ptype Outer::Oenum" "type = enum class Outer::Oenum.*"
+gdb_test "ptype foobar<int>::Foo" "type = struct Foo.*"
+gdb_test "ptype foobar<int>::Bar" "type = struct Bar.*"
+gdb_test "ptype foobar<int>::Baz" "type = struct Baz.*"
+gdb_test "ptype foobar<char>::Foo" "type = struct Foo.*"
+gdb_test "ptype foobar<char>::Bar" "type = struct Bar.*"
+gdb_test "ptype foobar<char>::Baz" "type = struct Baz.*"
+gdb_breakpoint "Outer::Inner::doit" message
+gdb_breakpoint "main::Foo::doit" message
+gdb_breakpoint "main::Bar::doit" message
+gdb_breakpoint "main::Baz::doit" message
+gdb_breakpoint "foobar<int>(int)::Foo::doit" message
+gdb_breakpoint "foobar<int>(int)::Bar::doit" message
+gdb_breakpoint "foobar<int>(int)::Baz::doit" message
+gdb_breakpoint "foobar<char>(int)::Foo::doit" message
+gdb_breakpoint "foobar<char>(int)::Bar::doit" message
+gdb_breakpoint "foobar<char>(int)::Baz::doit" message

gdb/testsuite/gdb.cp/subtypes.h

@@ -0,0 +1,50 @@
+/* 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/>.  */
+
+/* A template that defines subtypes.  */
+
+template <typename T>
+T foobar (int arg)
+{
+  struct Foo
+  {
+    T doit (void) { return 1; }
+  } foo;
+
+  struct Bar
+  {
+    T doit (void) { return 2; }
+  } bar;
+
+  struct Baz
+  {
+    T doit (void) { return 3; }
+  } baz;
+
+  return arg - foo.doit () - bar.doit () - baz.doit ();
+}
+
+/* A structure that defines other types.  */
+
+struct Outer
+{
+  enum class Oenum { OA, OB, OC, OD };
+  struct Inner;
+  Inner *p;
+  Oenum e;
+  Outer ();
+};