[Ada] Clean up uses of Esize and RM_Size

gcc/ada/

	* einfo-utils.adb: Add support (currently disabled) for using
	"initial zero" instead of "Uint_0" to represent "unknown".  Call
	Known_ functions, instead of evilly duplicating their code
	inline.
	* fe.h (No_Uint_To_0): New function to convert No_Uint to
	Uint_0, in order to preserve existing behavior.
	(Copy_Esize, Copy_RM_Size): New imports from Einfo.Utils.
	* cstand.adb: Set size fields of Standard_Debug_Renaming_Type
	and Standard_Exception_Type.
	* checks.adb, exp_attr.adb, exp_ch3.adb, exp_ch5.adb,
	exp_ch6.adb, exp_pakd.adb, exp_util.adb, freeze.adb, itypes.adb,
	layout.adb, repinfo.adb, sem_attr.adb, sem_ch12.adb,
	sem_ch13.adb, sem_ch13.ads, sem_ch3.adb, sem_ch7.adb,
	sem_util.adb: Protect calls with Known_..., use Copy_...  Remove
	assumption that Uint_0 represents "unknown".
	* types.ads (Nonzero_Int): New subtype.
	* gcc-interface/decl.c, gcc-interface/trans.c: Protect calls
	with Known_... and use Copy_...  as appropriate, to avoid
	blowing up in unknown cases. Similarly, call No_Uint_To_0 to
	preserve existing behavior.

1 files changed, 8 insertions, 6 deletions

diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb
index 9540089..b44bbe3 100644
--- a/gcc/ada/sem_attr.adb
+++ b/gcc/ada/sem_attr.adb
@@ -8124,13 +8124,13 @@ package body Sem_Attr is
       end if;
 
       --  If we are asked to evaluate an attribute where the prefix is a
-      --  non-frozen generic actual type whose RM_Size is still set to zero,
+      --  non-frozen generic actual type whose RM_Size has not been set,
       --  then abandon the effort.
 
       if Is_Type (P_Entity)
         and then (not Is_Frozen (P_Entity)
                    and then Is_Generic_Actual_Type (P_Entity)
-                   and then RM_Size (P_Entity) = 0)
+                   and then not Known_RM_Size (P_Entity))
 
         --  However, the attribute Unconstrained_Array must be evaluated,
         --  since it is documented to be a static attribute (and can for
@@ -9881,9 +9881,9 @@ package body Sem_Attr is
             P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
 
          begin
-            if Is_Scalar_Type (P_TypeA)
-              or else RM_Size (P_TypeA) /= Uint_0
-            then
+            pragma Assert
+              (if Is_Scalar_Type (P_TypeA) then Known_RM_Size (P_TypeA));
+            if Known_RM_Size (P_TypeA) then
                --  VADS_Size case
 
                if Id = Attribute_VADS_Size or else Use_VADS_Size then
@@ -10159,7 +10159,9 @@ package body Sem_Attr is
          P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
 
       begin
-         if Is_Scalar_Type (P_TypeA) or else RM_Size (P_TypeA) /= Uint_0 then
+         pragma Assert
+           (if Is_Scalar_Type (P_TypeA) then Known_RM_Size (P_TypeA));
+         if Known_RM_Size (P_TypeA) then
             Fold_Uint (N, RM_Size (P_TypeA), Static);
          end if;
       end Value_Size;