[Ada] Error adding/subtracting pointer value to/from integral.

When trying to evaluate an expression which adds a pointer and
an integral, the evaluation succeeds if the pointer is on
the left handside of the operator, but not when it is on the right
handside:

    (gdb) p something'address + 0
    $1 = (system.address) 0x613418 <pck.something>
    (gdb) p 0 + something'address
    Argument to arithmetic operation not a number or boolean.

Same issue when doing subtractions:

    (gdb) p something'address - 0
    $2 = (system.address) 0x613418 <pck.something>
    (gdb) p 0 - something'address
    Argument to arithmetic operation not a number or boolean.

This patch enhances the Ada expression evaluator to handle
these two situations.

gdb/ChangeLog:

        * ada-lang.c (ada_evaluate_subexp) <BINOP_ADD>: Add handling
        of the case where the second operand is a pointer.
        <BINOP_SUB>: Likewise.

gdb/testsuite/ChangeLog:

        * gdb.ada/addr_arith: New testcase.

Tested on x86_64-linux.

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2014-10-14  Joel Brobecker  <brobecker@adacore.com>
+
+	* ada-lang.c (ada_evaluate_subexp) <BINOP_ADD>: Add handling
+	of the case where the second operand is a pointer.
+	<BINOP_SUB>: Likewise.
+
 2014-10-14  Sergio Durigan Junior  <sergiodj@redhat.com>
 
 	* breakpoint.c (bkpt_probe_insert_location): Call set_semaphore

gdb/ada-lang.c

@@ -10004,6 +10004,10 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
         return (value_from_longest
                  (value_type (arg1),
                   value_as_long (arg1) + value_as_long (arg2)));
+      if (TYPE_CODE (value_type (arg2)) == TYPE_CODE_PTR)
+        return (value_from_longest
+                 (value_type (arg2),
+                  value_as_long (arg1) + value_as_long (arg2)));
       if ((ada_is_fixed_point_type (value_type (arg1))
            || ada_is_fixed_point_type (value_type (arg2)))
           && value_type (arg1) != value_type (arg2))
@@ -10026,6 +10030,10 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
         return (value_from_longest
                  (value_type (arg1),
                   value_as_long (arg1) - value_as_long (arg2)));
+      if (TYPE_CODE (value_type (arg2)) == TYPE_CODE_PTR)
+        return (value_from_longest
+                 (value_type (arg2),
+                  value_as_long (arg1) - value_as_long (arg2)));
       if ((ada_is_fixed_point_type (value_type (arg1))
            || ada_is_fixed_point_type (value_type (arg2)))
           && value_type (arg1) != value_type (arg2))

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2014-10-14  Joel Brobecker  <brobecker@adacore.com>
+
+	* gdb.ada/addr_arith: New testcase.
+
 2014-10-14  Maciej W. Rozycki  <macro@codesourcery.com>
 
 	* gdb.dwarf2/dw2-case-insensitive-debug.S: Handle 64-bit pointers.

gdb/testsuite/gdb.ada/addr_arith.exp

@@ -0,0 +1,42 @@
+# Copyright 2014 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_na07_019
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
+  return -1
+}
+
+clean_restart ${testfile}
+
+set bp_location [gdb_get_line_number "START" ${testdir}/foo_na07_019.adb]
+if ![runto "foo_na07_019.adb:$bp_location" ] then {
+  perror "Couldn't run ${testfile}"
+  return
+}
+
+gdb_test "print something'address + 0" \
+         "\\(system\\.address\\) $hex <pck\\.something>"
+
+gdb_test "print 0 + something'address" \
+         "\\(system\\.address\\) $hex <pck\\.something>"
+
+gdb_test "print something'address - 0" \
+         "\\(system\\.address\\) $hex <pck\\.something>"
+
+gdb_test "print 0 - something'address" \
+         "\\(system\\.address\\) $hex.*"

gdb/testsuite/gdb.ada/addr_arith/foo_na07_019.adb

@@ -0,0 +1,21 @@
+--  Copyright 2014 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/>.
+
+with Pck; use Pck;
+
+procedure Foo_NA07_019 is
+begin
+   Increment (Something);  -- START
+end Foo_NA07_019;

gdb/testsuite/gdb.ada/addr_arith/pck.adb

@@ -0,0 +1,21 @@
+--  Copyright 2014 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/>.
+
+package body Pck is
+   procedure Increment (I : in out Integer) is
+   begin
+      I := I + 1;
+   end Increment;
+end Pck;

gdb/testsuite/gdb.ada/addr_arith/pck.ads

@@ -0,0 +1,19 @@
+--  Copyright 2014 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/>.
+
+package Pck is
+   Something : Integer := 0;
+   procedure Increment (I : in out Integer);
+end Pck;