Ada: fix bad handling in ada_convert_actual

Using this small example:

procedure Foo is

   type Integer_Access is access all Integer;

   procedure P (A : Integer_Access) is
   begin
      null;
   end P;

begin
   P (null);
end Foo;

and doing this debug session:

(gdb) b p
Breakpoint 1 at 0x402d67: file foo.adb, line 7.
(gdb) print p(null)

Breakpoint 1, foo.p (a=0x641010) at foo.adb:10
...                  ^^^^^^^^^^

shows that something goes wrong between the initial null value and the
received parameter value in the 'f' function.
The value for the parameter 'a' we get is the address of the value we
would expect instead of the value itself. This can be checked by doing:

(gdb) p *a
$1 = 0

Before this fix, in ada_convert_value, this function was looking to the
actual value (the null value here) to determine if the formal (parameter
'a' in the procedure 'P' in this exemple) requires a pointer or not which
is a wrong assumption and leads to push the address of the value to the
inferior instead of the value itself.

This is fixed by this patch.

gdb/ChangeLog:

        * ada-lang.c (ada_convert_actual): Change the way actual value
        are passed to the inferior when the inferior expects a pointer type.

gdb/testsuite/ChangeLog:

        * gdb.ada/funcall_ptr: New testcase.

Tested on x86_64-linux.

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2017-12-18  Xavier Roirand  <roirand@adacore.com>
+
+	* ada-lang.c (ada_convert_actual): Change the way actual value
+	are passed to the inferior when the inferior expects a pointer type.
+
 2017-12-17  Stafford Horne  <shorne@gmail.com>
 
 	* gdb/or1k-tdep.c (show_or1k_debug): Fix function parameter alignment.

gdb/ada-lang.c

@@ -4513,7 +4513,7 @@ ada_convert_actual (struct value *actual, struct type *formal_type0)
       if (TYPE_CODE (formal_target) == TYPE_CODE_ARRAY
           && ada_is_array_descriptor_type (actual_target))
 	result = desc_data (actual);
-      else if (TYPE_CODE (actual_type) != TYPE_CODE_PTR)
+      else if (TYPE_CODE (formal_type) != TYPE_CODE_PTR)
         {
           if (VALUE_LVAL (actual) != lval_memory)
             {

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2017-12-18  Xavier Roirand  <roirand@adacore.com>
+
+	* gdb.ada/funcall_ptr: New testcase.
+
 2017-12-15  Sergio Durigan Junior  <sergiodj@redhat.com>
 
 	PR cli/16224

gdb/testsuite/gdb.ada/funcall_ptr.exp

@@ -0,0 +1,40 @@
+# Copyright 2017 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}
+
+set bp_location [gdb_get_line_number "BREAK" ${testdir}/foo.adb]
+runto "foo.adb:$bp_location"
+
+gdb_test "print pck.ga" " = \\(access integer\\) 0x0" \
+         "Check that initial value of GA is null"
+
+gdb_test_no_output "call pck.p(0x1234)"
+
+# Check that argument 'A' was passed correctly in the call to Pck.P
+# above. We check that, by printing GA global variable.
+# The GA global variable is set with the value of parameter 'A' inside p
+# procedure hence should be 0x1234 after the call above.
+
+gdb_test "print pck.ga" " = \\(access integer\\) 0x1234" \
+         "Check that value of GA is 0x1234"

gdb/testsuite/gdb.ada/funcall_ptr/foo.adb

@@ -0,0 +1,21 @@
+--  Copyright 2017 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 is
+begin
+   P (null); -- BREAK
+end Foo;

gdb/testsuite/gdb.ada/funcall_ptr/pck.adb

@@ -0,0 +1,23 @@
+--  Copyright 2017 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 P (A : Integer_Access) is
+   begin
+      GA := A;
+   end P;
+
+end Pck;

gdb/testsuite/gdb.ada/funcall_ptr/pck.ads

@@ -0,0 +1,24 @@
+--  Copyright 2017 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
+
+   type Integer_Access is access all Integer;
+
+   procedure P (A : Integer_Access);
+
+   GA : Integer_Access;
+
+end Pck;