[Ada] Handle non-default C++ constructor call of non-tagged type

[Arnaud Charlet]

This patch enables the frontend support for calling C++ constructors
of non-tagged types. This is required since the equivalent Ada type
of a C++ class that has no virtual methods is a non-tagged limited
record type. After this patch the following test executes well.

class demo
{
  int value;
public:
  demo (int init_value);
  void display (void);
};

#include "stdio.h"
#include "demo_class.h"

demo::demo (int init_value)
{
  this->value = init_value;
}

void demo::display ()
{
  printf ("value %d\n", value);
}


with Demo_Class_H;
procedure Call_Cpp is
   Obj2 : aliased Demo_Class_H.Class_Demo.demo :=
            Demo_Class_H.Class_Demo.New_Demo (42);
begin
   Demo_Class_H.Class_Demo.Display (Obj2'Access);
end Call_Cpp;

Command:
  g++ -c -fdump-ada-spec -C demo_class.h
  gnatchop -w -gnat05 all.ada
  gprbuild -q demo.gpr
  ./call_cpp

Output:
  value 42

Tested on x86_64-pc-linux-gnu, committed on trunk

2011-09-01  Javier Miranda  <mira...@adacore.com>

        * exp_ch3.adb (Expand_N_Object_Declaration): Handle non-default
        constructor calls associated with non-tagged record types.


Index: exp_ch3.adb
===================================================================
--- exp_ch3.adb (revision 178381)
+++ exp_ch3.adb (working copy)
@@ -5129,9 +5129,13 @@
                              Loc))));
                end;
 
-            elsif Is_Tagged_Type (Typ)
-              and then Is_CPP_Constructor_Call (Expr)
-            then
+            --  Handle C++ constructor calls. Note that we do not check that
+            --  Typ is a tagged type since the equivalent Ada type of a C++
+            --  class that has no virtual methods is a non-tagged limited
+            --  record type.
+
+            elsif Is_CPP_Constructor_Call (Expr) then
+
                --  The call to the initialization procedure does NOT freeze the
                --  object being initialized.