Patchwork [Ada] Clean up handling of msgs for biasing

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Submitter Arnaud Charlet
Date Oct. 4, 2010, 2:10 p.m.
Message ID <20101004141000.GA8229@adacore.com>
Download mbox | patch
Permalink /patch/66679/
State New
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Comments

Arnaud Charlet - Oct. 4, 2010, 2:10 p.m.
This patch factors code and cleans up the handling of warnings for
biased representation. It also removes the useless and wrong attempt
to use biased representation in the case of an enumeration rep clause.
This attempt never succeeded anyway. The following test shows the
new form of the warning messages:

     1. package biasname is
     2.    type b is new integer range 7 .. 8;
     3.    type r is record
     4.       c : b;
     5.    end record;
     6.    for r use record
     7.       c at 0 range 0 .. 0;
              |
        >>> warning: component clause forces biased
            representation for "c"

     8.    end record;
     9.    type a is array (1 .. 16) of b;
    10.    for a'component_size use 1;
           |
        >>> warning: component size clause forces biased
            representation for subtype of "b"

    11.    type p is new integer range 7 .. 8;
    12.    for p'size use 1;
           |
        >>> warning: size clause forces biased
            representation for "p"

    13. end biasname;

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

2010-10-04  Robert Dewar  <dewar@adacore.com>

	* sem_ch13.adb (Set_Biased): New procedure, now used throughout, adds
	name of entity to biased warning msg.
	(Analyze_Enumeration_Representation_Clause): Remove attempt to use
	biased rep (wrong and never worked anyway).

Patch

Index: sem_ch13.adb
===================================================================
--- sem_ch13.adb	(revision 164939)
+++ sem_ch13.adb	(working copy)
@@ -106,6 +106,16 @@  package body Sem_Ch13 is
    --  renaming_as_body. For tagged types, the specification is one of the
    --  primitive specs.
 
+   procedure Set_Biased
+     (E      : Entity_Id;
+      N      : Node_Id;
+      Msg    : String;
+      Biased : Boolean := True);
+   --  If Biased is True, sets Has_Biased_Representation flag for E, and
+   --  outputs a warning message at node N if Warn_On_Biased_Representation is
+   --  is True. This warning inserts the string Msg to describe the construct
+   --  causing biasing.
+
    ----------------------------------------------
    -- Table for Validate_Unchecked_Conversions --
    ----------------------------------------------
@@ -1342,17 +1352,11 @@  package body Sem_Ch13 is
                      Set_Esize                     (New_Ctyp, Csize);
                      Set_RM_Size                   (New_Ctyp, Csize);
                      Init_Alignment                (New_Ctyp);
-                     Set_Has_Biased_Representation (New_Ctyp, True);
                      Set_Is_Itype                  (New_Ctyp, True);
                      Set_Associated_Node_For_Itype (New_Ctyp, U_Ent);
 
                      Set_Component_Type (Btype, New_Ctyp);
-
-                     if Warn_On_Biased_Representation then
-                        Error_Msg_N
-                          ("?component size clause forces biased "
-                           & "representation", N);
-                     end if;
+                     Set_Biased (New_Ctyp, N, "component size clause");
                   end if;
 
                   Set_Component_Size (Btype, Csize);
@@ -1574,12 +1578,7 @@  package body Sem_Ch13 is
                  or else Has_Small_Clause (U_Ent)
                then
                   Check_Size (Expr, Etyp, Size, Biased);
-                     Set_Has_Biased_Representation (U_Ent, Biased);
-
-                  if Biased and Warn_On_Biased_Representation then
-                     Error_Msg_N
-                       ("?size clause forces biased representation", N);
-                  end if;
+                  Set_Biased (U_Ent, N, "size clause", Biased);
                end if;
 
                --  For types set RM_Size and Esize if possible
@@ -1953,12 +1952,7 @@  package body Sem_Ch13 is
             else
                if Is_Elementary_Type (U_Ent) then
                   Check_Size (Expr, U_Ent, Size, Biased);
-                  Set_Has_Biased_Representation (U_Ent, Biased);
-
-                  if Biased and Warn_On_Biased_Representation then
-                     Error_Msg_N
-                       ("?value size clause forces biased representation", N);
-                  end if;
+                  Set_Biased (U_Ent, N, "value size clause", Biased);
                end if;
 
                Set_RM_Size (U_Ent, Size);
@@ -2362,7 +2356,8 @@  package body Sem_Ch13 is
                   --  If biasing worked, indicate that we now have biased rep
 
                   else
-                     Set_Has_Biased_Representation (Enumtype);
+                     Set_Biased
+                       (Enumtype, Size_Clause (Enumtype), "size clause");
                   end if;
                end if;
 
@@ -2807,13 +2802,8 @@  package body Sem_Ch13 is
                            Esize (Comp),
                            Biased);
 
-                        Set_Has_Biased_Representation (Comp, Biased);
-
-                        if Biased and Warn_On_Biased_Representation then
-                           Error_Msg_F
-                             ("?component clause forces biased "
-                              & "representation", CC);
-                        end if;
+                        Set_Biased
+                          (Comp, First_Node (CC), "component clause", Biased);
 
                         if Present (Ocomp) then
                            Set_Component_Clause     (Ocomp, CC);
@@ -2825,6 +2815,10 @@  package body Sem_Ch13 is
                            Set_Normalized_Position_Max
                              (Ocomp, Normalized_Position (Ocomp));
 
+                           --  Note: we don't use Set_Biased here, because we
+                           --  already gave a warning above if needed, and we
+                           --  would get a duplicate for the same name here.
+
                            Set_Has_Biased_Representation
                              (Ocomp, Has_Biased_Representation (Comp));
                         end if;
@@ -4856,7 +4850,6 @@  package body Sem_Ch13 is
       --  cases were already dealt with.
 
       elsif Is_Enumeration_Type (T1) then
-
          Enumeration_Case : declare
             L1, L2 : Entity_Id;
 
@@ -4884,6 +4877,27 @@  package body Sem_Ch13 is
       end if;
    end Same_Representation;
 
+   ----------------
+   -- Set_Biased --
+   ----------------
+
+   procedure Set_Biased
+     (E      : Entity_Id;
+      N      : Node_Id;
+      Msg    : String;
+      Biased : Boolean := True)
+   is
+   begin
+      if Biased then
+         Set_Has_Biased_Representation (E);
+
+         if Warn_On_Biased_Representation then
+            Error_Msg_NE
+              ("?" & Msg & " forces biased representation for&", N, E);
+         end if;
+      end if;
+   end Set_Biased;
+
    --------------------
    -- Set_Enum_Esize --
    --------------------