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.

3 files changed, 68 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.ada/funcall_ptr/foo.adb b/gdb/testsuite/gdb.ada/funcall_ptr/foo.adb
new file mode 100644
index 0000000..25a5aef
--- /dev/null
+++ b/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;
diff --git a/gdb/testsuite/gdb.ada/funcall_ptr/pck.adb b/gdb/testsuite/gdb.ada/funcall_ptr/pck.adb
new file mode 100644
index 0000000..faf91bf
--- /dev/null
+++ b/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;
diff --git a/gdb/testsuite/gdb.ada/funcall_ptr/pck.ads b/gdb/testsuite/gdb.ada/funcall_ptr/pck.ads
new file mode 100644
index 0000000..9595b71
--- /dev/null
+++ b/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;