checks.adb, [...]: Improve warnings for address overlays.

2007-09-26  Robert Dewar  <dewar@adacore.com>

	* checks.adb, gnat1drv.adb, sem_util.ads: Improve warnings for address
	overlays.

	* sem_ch13.ads, sem_ch13.adb: Improve warnings for address overlays
	(Analyze_Record_Representation_Clause): Suppress junk warning for
	missing component clause.
	(Analyze_Attribute_Definition_Clause, case Address): Apply the special
	tests for controlled type overlay to composites with controlled
	components.
	(Analyze_Record_Representation_Clause): Add reference for component name

From-SVN: r128785

gcc/ada/checks.adb

@@ -543,6 +543,7 @@ package body Checks is
             Error_Msg_FE
               ("\?program execution may be erroneous (RM 13.3(27))",
                Aexp, E);
+            Set_Address_Warning_Posted (AC);
          end if;
       end Compile_Time_Bad_Alignment;
 
@@ -626,6 +627,7 @@ package body Checks is
                   Error_Msg_FE
                     ("\?program execution may be erroneous", Aexp, E);
                   Size_Warning_Output := True;
+                  Set_Address_Warning_Posted (AC);
                end if;
             end if;
          end;

gcc/ada/gnat1drv.adb

@@ -442,6 +442,7 @@ begin
       if Compilation_Errors then
          Treepr.Tree_Dump;
          Sem_Ch13.Validate_Unchecked_Conversions;
+         Sem_Ch13.Validate_Address_Clauses;
          Errout.Output_Messages;
          Namet.Finalize;
 
@@ -622,6 +623,7 @@ begin
          Write_Eol;
 
          Sem_Ch13.Validate_Unchecked_Conversions;
+         Sem_Ch13.Validate_Address_Clauses;
          Errout.Finalize (Last_Call => True);
          Errout.Output_Messages;
          Treepr.Tree_Dump;
@@ -654,6 +656,7 @@ begin
                    or else Targparm.VM_Target /= No_VM)
       then
          Sem_Ch13.Validate_Unchecked_Conversions;
+         Sem_Ch13.Validate_Address_Clauses;
          Errout.Finalize (Last_Call => True);
          Errout.Output_Messages;
          Write_ALI (Object => False);
@@ -704,6 +707,11 @@ begin
 
       Sem_Ch13.Validate_Unchecked_Conversions;
 
+      --  Validate address clauses (again using alignment values annotated
+      --  by the backend where possible).
+
+      Sem_Ch13.Validate_Address_Clauses;
+
       --  Now we complete output of errors, rep info and the tree info. These
       --  are delayed till now, since it is perfectly possible for gigi to
       --  generate errors, modify the tree (in particular by setting flags

gcc/ada/sem_ch13.ads

@@ -161,4 +161,10 @@ package Sem_Ch13 is
    --  The reason it is called that late is to take advantage of any
    --  back-annotation of size and alignment performed by the backend.
 
+   procedure Validate_Address_Clauses;
+   --  This is called after the back end has been called (and thus after the
+   --  alignments of objects have been back annotated). It goes through the
+   --  table of saved address clauses checking for suspicious alignments and
+   --  if necessary issuing warnings.
+
 end Sem_Ch13;

gcc/ada/sem_util.ads

@@ -292,6 +292,13 @@ package Sem_Util is
    --  denotes when analyzed. Subsequent uses of this id on a different
    --  type denote the discriminant at the same position in this new type.
 
+   function Find_Overlaid_Object (N : Node_Id) return Entity_Id;
+   --  The node N should be an address representation clause. This function
+   --  checks if the target expression is the address of some stand alone
+   --  object (variable or constant), and if so, returns its entity. If N is
+   --  not an address representation clause, or if it is not possible to
+   --  determine that the address is of this form, then Empty is returned.
+
    function Find_Overridden_Synchronized_Primitive
      (Def_Id      : Entity_Id;
       First_Hom   : Entity_Id;
@@ -304,6 +311,11 @@ package Sem_Util is
    --  declared inside the scope of the synchronized type or after. Return
    --  the overridden entity or Empty.
 
+   function Find_Static_Alternative (N : Node_Id) return Node_Id;
+   --  N is a case statement whose expression is a compile-time value.
+   --  Determine the alternative chosen, so that the code of non-selected
+   --  alternatives, and the warnings that may apply to them, are removed.
+
    function First_Actual (Node : Node_Id) return Node_Id;
    --  Node is an N_Function_Call or N_Procedure_Call_Statement node. The
    --  result returned is the first actual parameter in declaration order
@@ -321,11 +333,6 @@ package Sem_Util is
    --  name in upper case. An ASCII.NUL is appended as the last character.
    --  The names in the string are generated by Namet.Get_Decoded_Name_String.
 
-   function Find_Static_Alternative (N : Node_Id) return Node_Id;
-   --  N is a case statement whose expression is a compile-time value.
-   --  Determine the alternative chosen, so that the code of non-selected
-   --  alternatives, and the warnings that may apply to them, are removed.
-
    procedure Gather_Components
      (Typ           : Entity_Id;
       Comp_List     : Node_Id;