[Ada] More precise handling of Size/Object_Size in GNATprove

GNATprove does a partial expansion which did not allow getting the
most precise value for attributes Size/Object_Size. Now fixed.

There is no impact on compilation.

2019-08-12  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* exp_attr.adb, exp_attr.ads (Expand_Size_Attribute): New
	procedure to share part of the attribute expansion with
	GNATprove mode.
	(Expand_N_Attribute_Reference): Extract part of the
	Size/Object_Size expansion in the new procedure
	Expand_Size_Attribute.
	* exp_spark.adb (Expand_SPARK_N_Attribute_Reference): Expand
	Size/Object_Size attributes using the new procedure
	Expand_Size_Attribute.

From-SVN: r274290

gcc/ada/ChangeLog

 2019-08-12  Yannick Moy  <moy@adacore.com>
 
+	* exp_attr.adb, exp_attr.ads (Expand_Size_Attribute): New
+	procedure to share part of the attribute expansion with
+	GNATprove mode.
+	(Expand_N_Attribute_Reference): Extract part of the
+	Size/Object_Size expansion in the new procedure
+	Expand_Size_Attribute.
+	* exp_spark.adb (Expand_SPARK_N_Attribute_Reference): Expand
+	Size/Object_Size attributes using the new procedure
+	Expand_Size_Attribute.
+
+2019-08-12  Yannick Moy  <moy@adacore.com>
+
 	* exp_spark.adb (Expand_SPARK_N_Attribute_Reference): Only
 	expand Enum_Rep attribute when its parameter is a literal.
 

gcc/ada/exp_attr.ads

@@ -31,4 +31,9 @@ package Exp_Attr is
 
    procedure Expand_N_Attribute_Reference (N : Node_Id);
 
+   procedure Expand_Size_Attribute (N : Node_Id);
+   --  Handles part of the expansion of attributes 'Object_Size, 'Size,
+   --  'Value_Size, and 'VADS_Size, so that it can also be used in the special
+   --  expansion in GNATprove mode.
+
 end Exp_Attr;

gcc/ada/exp_spark.adb

@@ -227,6 +227,13 @@ package body Exp_SPARK is
             end if;
          end;
 
+      elsif Attr_Id = Attribute_Object_Size
+        or else Attr_Id = Attribute_Size
+        or else Attr_Id = Attribute_Value_Size
+        or else Attr_Id = Attribute_VADS_Size
+      then
+         Exp_Attr.Expand_Size_Attribute (N);
+
       --  For attributes which return Universal_Integer, introduce a conversion
       --  to the expected type with the appropriate check flags set.
 
@@ -241,10 +248,6 @@ package body Exp_SPARK is
         or else Attr_Id = Attribute_Pos
         or else Attr_Id = Attribute_Position
         or else Attr_Id = Attribute_Range_Length
-        or else Attr_Id = Attribute_Object_Size
-        or else Attr_Id = Attribute_Size
-        or else Attr_Id = Attribute_Value_Size
-        or else Attr_Id = Attribute_VADS_Size
         or else Attr_Id = Attribute_Aft
         or else Attr_Id = Attribute_Max_Alignment_For_Allocation
       then