[commit/Ada] result of function call as a parameter to another function call

[commit/Ada] result of function call as a parameter to another function call

[Joel Brobecker]

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Hello,

As I hinted a littler earlier, there is a problem in the debugger
where we use a the result from a function call as parameter to another
function call.  The problem arises when the parameter is a reference
type.

Assuming My_Parameter is a variable of type Parameter which is
defined as a record (the equivalent of a C "struct"):

   (gdb) p ident (ident (my_parameter))
   Attempt to take address of value not located in memory.

There were a couple of issues: One was an omission during the
construction of a value (inside ada-lang.c:ensure_lval), where
we forgot to set the value->lval; And another in the handling
of formals that are reference types.

Paul fixed the problem as follow:

2008-01-08  Paul Hilfinger  <hilfinger@adacore.com>

        * ada-lang.c (ensure_lval): Fix value lval kind.
        (convert_actual): Add handling for arguments passed by reference.

I also wrote a testcase:

2008-01-08  Joel Brobecker  <brobecker@adacore.com>

        * gdb.ada/funcall_param: New test program.
        * gdb.ada/funcall_param.exp: New testcase.

Tested on x86-linux, no regression.

I checked the ada-lang.c change in, but I will defer a bit the checkin
of the testcase because the testcase itself depends on another change
that I need to make (Ada parameter coercion, see
http://www.sourceware.org/ml/gdb-patches/2008-01/msg00129.html) in order
to pass.

-- 
Joel

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Index: ada-lang.c
===================================================================
--- ada-lang.c	(revision 101)
+++ ada-lang.c	(revision 102)
@@ -3929,6 +3929,7 @@ ensure_lval (struct value *val, CORE_ADD
 	  if (gdbarch_frame_align_p (current_gdbarch))
 	    *sp = gdbarch_frame_align (current_gdbarch, *sp);
 	}
+      VALUE_LVAL (val) = lval_memory;
 
       write_memory (VALUE_ADDRESS (val), value_contents_raw (val), len);
     }
@@ -3957,11 +3958,13 @@ convert_actual (struct value *actual, st
   if (ada_is_array_descriptor_type (formal_target)
       && TYPE_CODE (actual_target) == TYPE_CODE_ARRAY)
     return make_array_descriptor (formal_type, actual, sp);
-  else if (TYPE_CODE (formal_type) == TYPE_CODE_PTR)
+  else if (TYPE_CODE (formal_type) == TYPE_CODE_PTR
+	   || TYPE_CODE (formal_type) == TYPE_CODE_REF)
     {
+      struct value *result;
       if (TYPE_CODE (formal_target) == TYPE_CODE_ARRAY
           && ada_is_array_descriptor_type (actual_target))
-        return desc_data (actual);
+	result = desc_data (actual);
       else if (TYPE_CODE (actual_type) != TYPE_CODE_PTR)
         {
           if (VALUE_LVAL (actual) != lval_memory)
@@ -3974,8 +3977,11 @@ convert_actual (struct value *actual, st
                       TYPE_LENGTH (actual_type));
               actual = ensure_lval (val, sp);
             }
-          return value_addr (actual);
+          result = value_addr (actual);
         }
+      else
+	return actual;
+      return value_cast_pointers (formal_type, result);
     }
   else if (TYPE_CODE (actual_type) == TYPE_CODE_PTR)
     return ada_value_ind (actual);

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Index: gdb.ada/funcall_param.exp
===================================================================
--- gdb.ada/funcall_param.exp	(revision 0)
+++ gdb.ada/funcall_param.exp	(revision 103)
@@ -0,0 +1,46 @@
+# Copyright 2008 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/>.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+load_lib "ada.exp"
+
+set testdir "funcall_param"
+set testfile "${testdir}/foo"
+set srcfile ${srcdir}/${subdir}/${testfile}.adb
+set binfile ${objdir}/${subdir}/${testfile}
+
+file mkdir ${objdir}/${subdir}/${testdir}
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug]] != "" } {
+  return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+set bp_location [gdb_get_line_number "STOP" ${testdir}/foo.adb]
+runto "foo.adb:$bp_location"
+
+# Test printing and type-printing of a tagged type that is not
+# class-wide.
+
+gdb_test "p ident (ident (my_parameter))" \
+         "\\(one => 1, two => 2, three => 3\\)" \
+         "p ident (ident (my_parameter))"
+
Index: gdb.ada/funcall_param/pck.adb
===================================================================
--- gdb.ada/funcall_param/pck.adb	(revision 0)
+++ gdb.ada/funcall_param/pck.adb	(revision 103)
@@ -0,0 +1,28 @@
+--  Copyright 2008 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
+
+   function Ident (P : Parameter) return Parameter is
+   begin
+      return P;
+   end Ident;
+
+   procedure Do_Nothing (P : in out Parameter) is
+   begin
+      null;
+   end Do_Nothing;
+
+end Pck;
Index: gdb.ada/funcall_param/pck.ads
===================================================================
--- gdb.ada/funcall_param/pck.ads	(revision 0)
+++ gdb.ada/funcall_param/pck.ads	(revision 103)
@@ -0,0 +1,28 @@
+--  Copyright 2008 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 Parameter is record
+      One : Integer;
+      Two : Integer;
+      Three : Integer;
+   end record;
+
+   function Ident (P : Parameter) return Parameter;
+
+   procedure Do_Nothing (P : in out Parameter);
+
+end Pck;
Index: gdb.ada/funcall_param/foo.adb
===================================================================
--- gdb.ada/funcall_param/foo.adb	(revision 0)
+++ gdb.ada/funcall_param/foo.adb	(revision 103)
@@ -0,0 +1,22 @@
+--  Copyright 2008 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
+   My_Parameter : Parameter := Ident (P => (1, 2, 3));
+begin
+   Do_Nothing (My_Parameter);  -- STOP
+end Foo;

Re: [commit/Ada] result of function call as a parameter to another function call

[Joel Brobecker]

> 2008-01-08  Joel Brobecker  <brobecker@adacore.com>
> 
>         * gdb.ada/funcall_param: New test program.
>         * gdb.ada/funcall_param.exp: New testcase.
> 
> Tested on x86-linux, no regression.
> 
> I checked the ada-lang.c change in, but I will defer a bit the checkin
> of the testcase because the testcase itself depends on another change
> that I need to make (Ada parameter coercion, see
> http://www.sourceware.org/ml/gdb-patches/2008-01/msg00129.html) in order
> to pass.

All conditions are now met, so I committed the testcase as well.

-- 
Joel