Fix infinite recursion when printing static member with typedef

The original problem was fixed (see related PR 22242). But using a typedef
as the declared type for a static member variable, as commented in this PR,
is still causing gdb to get into infinite loop when printing the static
member's value. This problem can be reproduced as follows:

% cat t.cc
class A {
    typedef A type;
public:
    bool operator==(const type& other) { return true; }

    static const type INSTANCE;
};

const A A::INSTANCE;

int main() {
    A a;
    if (a == A::INSTANCE) {
        return -1;
    }
    return 0;
}
% g++ -g t.cc
% gdb -ex "start" -ex "p a" a.out

The fix is rather trivial - in cp_print_static_field(), should call
check_typedef() to get the static member's real type and use it to
check whether it's a struct or an array.

As Simon suggested, I've added a new test case to the testsuite
and am passing the original type, not the real type, as argument
to both cp_print_value_fields() and val_print().

Re-tested on both aarch64-linux-gnu and amd64-linux-gnu. No regressions.

2 files changed, 71 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.cp/static-typedef-print.cc b/gdb/testsuite/gdb.cp/static-typedef-print.cc
new file mode 100644
index 0000000..5faff3e
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/static-typedef-print.cc
@@ -0,0 +1,34 @@
+/* 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/>.  */
+
+class A {
+    typedef A type;
+public:
+    bool operator==(const type& other) { return true; }
+
+    static const type INSTANCE;
+};
+
+const A A::INSTANCE = {};
+
+int main() {
+    A a;
+    if (a == A::INSTANCE) {
+        return -1;
+    }
+    return 0;
+}
diff --git a/gdb/testsuite/gdb.cp/static-typedef-print.exp b/gdb/testsuite/gdb.cp/static-typedef-print.exp
new file mode 100644
index 0000000..ff6756e
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/static-typedef-print.exp
@@ -0,0 +1,37 @@
+# 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/>.
+
+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 "print a" \
+         "static INSTANCE = <same as static member of an already seen type>}}.*" \
+         "print static member"