[commit/Ada] crash printing optimized out variant type

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

One of the positive consequences of http://gcc.gnu.org/PR54534
(regression in GCC 4.7)...

Assuming the following declarations:

   type Discriminants_Record (A : Integer; B : Boolean) is record
      C : Float;
   end record;
   Z : Discriminants_Record := (A => 1, B => False, C => 2.0);

If variable Z is not used, and the compiler optimizes it out,
GDB would crash as follow:

    (gdb) print Z
    /[...]/gdb/valops.c:1121: internal-error: Unexpected lazy value type.

This is because the ada-lang module forgot to set the optimized_out
flag in the value returned by ada_evaluate_subexp during the value's
"fixing" process.  Later on, when trying to print the resulting value,
GDB finds that the value is still lazily allocated, and thus tries to
fetch it. But this is not allowed for not_lval values, hence the internal
error.

gdb/ChangeLog:

        * ada-lang.c (coerce_unspec_val_to_type): Make sure that
        the optimized_out flag is preserved.

gdb/testsuite/ChangeLog:

        * gdb.ada/optim_drec: New testcase.

Tested on x86_64-linux, with older and newer compilers. No regression.
Checked in.

-- 
Joel

---
 gdb/ChangeLog                            |    5 ++++
 gdb/ada-lang.c                           |    1 +
 gdb/testsuite/ChangeLog                  |    4 +++
 gdb/testsuite/gdb.ada/optim_drec.exp     |   34 ++++++++++++++++++++++++++++++
 gdb/testsuite/gdb.ada/optim_drec/foo.adb |   25 ++++++++++++++++++++++
 5 files changed, 69 insertions(+), 0 deletions(-)
 create mode 100644 gdb/testsuite/gdb.ada/optim_drec.exp
 create mode 100644 gdb/testsuite/gdb.ada/optim_drec/foo.adb

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c00a32d..f9560f8 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2012-09-10  Joel Brobecker  <brobecker@adacore.com>
+
+	* ada-lang.c (coerce_unspec_val_to_type): Make sure that
+	the optimized_out flag is preserved.
+
 2012-09-10  Keith Seitz  <keiths@redhat.com>
 
 	PR gdb/13483
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index bba045b..f45815f 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -581,6 +581,7 @@ coerce_unspec_val_to_type (struct value *val, struct type *type)
       set_value_bitsize (result, value_bitsize (val));
       set_value_bitpos (result, value_bitpos (val));
       set_value_address (result, value_address (val));
+      set_value_optimized_out (result, value_optimized_out (val));
       return result;
     }
 }
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index b33b6fa..e9db80f 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2012-09-10  Joel Brobecker  <brobecker@adacore.com>
+
+	* gdb.ada/optim_drec: New testcase.
+
 2012-09-10  Doug Evans  <dje@google.com>
 
 	* boards/fission.exp: Explicitly mark "board" as not remote.
diff --git a/gdb/testsuite/gdb.ada/optim_drec.exp b/gdb/testsuite/gdb.ada/optim_drec.exp
new file mode 100644
index 0000000..6508e04
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/optim_drec.exp
@@ -0,0 +1,34 @@
+# Copyright 2012 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/>.
+
+load_lib "ada.exp"
+
+standard_ada_testfile foo
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
+  return -1
+}
+
+clean_restart ${testfile}
+
+if ![runto "foo" ] then {
+  perror "Couldn't run ${testfile}"
+  return
+}
+
+gdb_test "print z" \
+         "= (\\(a => .*, b => .*, c => .*\\)|<optimized out>)"
+
+
diff --git a/gdb/testsuite/gdb.ada/optim_drec/foo.adb b/gdb/testsuite/gdb.ada/optim_drec/foo.adb
new file mode 100644
index 0000000..88fd652
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/optim_drec/foo.adb
@@ -0,0 +1,25 @@
+--  Copyright 2012 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/>.
+
+procedure Foo is
+   type Discriminants_Record (A : Integer; B : Boolean) is record
+      C : Float;
+   end record;
+   --  The following variable is unused on purpose, and might be
+   --  optimized out by the compiler.
+   Z : Discriminants_Record := (A => 1, B => False, C => 2.0);
+begin
+   null;
+end Foo;
-- 
1.7.1