[Ada] Clean up Uint fields

gcc/ada/

	* uintp.ads, types.h: New subtypes of Uint: Valid_Uint, Unat,
	Upos, Nonzero_Uint with predicates. These correspond to new
	field types in Gen_IL.
	* gen_il-types.ads (Valid_Uint, Unat, Upos, Nonzero_Uint): New
	field types.
	* einfo-utils.ads, einfo-utils.adb, fe.h (Known_Alignment,
	Init_Alignment): Use the initial zero value to represent
	"unknown". This will ensure that if Alignment is called before
	Set_Alignment, the compiler will blow up (if assertions are
	enabled).
	* atree.ads, atree.adb, atree.h, gen_il-gen.adb
	(Get_Valid_32_Bit_Field): New generic low-level getter for
	subtypes of Uint.
	(Copy_Alignment): New procedure to copy Alignment field even
	when Unknown.
	(Init_Object_Size_Align, Init_Size_Align): Do not bypass the
	Init_ procedures.
	* exp_pakd.adb, freeze.adb, layout.adb, repinfo.adb,
	sem_util.adb: Protect calls to Alignment with Known_Alignment.
	Use Copy_Alignment when it might be unknown.
	* gen_il-gen-gen_entities.adb (Alignment,
	String_Literal_Length): Use type Unat instead of Uint, to ensure
	that the field is always Set_ before we get it, and that it is
	set to a nonnegative value.
	(Enumeration_Pos): Unat.
	(Enumeration_Rep): Valid_Uint. Can be negative, but must be
	valid before fetching.
	(Discriminant_Number): Upos.
	(Renaming_Map): Remove.
	* gen_il-gen-gen_nodes.adb (Char_Literal_Value, Reason): Unat.
	(Intval, Corresponding_Integer_Value): Valid_Uint.
	* gen_il-internals.ads: New functions for dealing with special
	defaults and new subtypes of Uint.
	* scans.ads: Correct comments.
	* scn.adb (Post_Scan): Do not set Intval to No_Uint; that is no
	longer allowed.
	* sem_ch13.adb (Analyze_Enumeration_Representation_Clause): Do
	not set Enumeration_Rep to No_Uint; that is no longer allowed.
	(Offset_Value): Protect calls to Alignment with Known_Alignment.
	* sem_prag.adb (Set_Atomic_VFA): Do not use Uint_0 to mean
	"unknown"; call Init_Alignment instead.
	* sinfo.ads: Minor comment fix.
	* treepr.adb: Deal with printing of new field types.
	* einfo.ads, gen_il-fields.ads (Renaming_Map): Remove.
	* gcc-interface/decl.c (gnat_to_gnu_entity): Use Known_Alignment
	before calling Alignment. This preserve some probably buggy
	behavior: if the alignment is not set, it previously defaulted
	to Uint_0; we now make that explicit.  Use Copy_Alignment,
	because "Set_Alignment (Y, Alignment (X));" no longer works when
	the Alignment of X has not yet been set.
	* gcc-interface/trans.c (process_freeze_entity): Use
	Copy_Alignment.

1 files changed, 17 insertions, 8 deletions

diff --git a/gcc/ada/einfo-utils.adb b/gcc/ada/einfo-utils.adb
index 21d7bfb..4690c8f 100644
--- a/gcc/ada/einfo-utils.adb
+++ b/gcc/ada/einfo-utils.adb
@@ -364,7 +364,7 @@ package body Einfo.Utils is
 
    procedure Init_Alignment (Id : E) is
    begin
-      Set_Alignment (Id, Uint_0);
+      Reinit_Field_To_Zero (Id, F_Alignment);
    end Init_Alignment;
 
    procedure Init_Alignment (Id : E; V : Int) is
@@ -452,6 +452,15 @@ package body Einfo.Utils is
       Set_RM_Size (Id, UI_From_Int (V));
    end Init_RM_Size;
 
+   procedure Copy_Alignment (To, From : E) is
+   begin
+      if Known_Alignment (From) then
+         Set_Alignment (To, Alignment (From));
+      else
+         Init_Alignment (To);
+      end if;
+   end Copy_Alignment;
+
    -----------------------------
    -- Init_Component_Location --
    -----------------------------
@@ -471,8 +480,8 @@ package body Einfo.Utils is
 
    procedure Init_Object_Size_Align (Id : E) is
    begin
-      Set_Esize (Id, Uint_0);
-      Set_Alignment (Id, Uint_0);
+      Init_Esize (Id);
+      Init_Alignment (Id);
    end Init_Object_Size_Align;
 
    ---------------
@@ -499,9 +508,9 @@ package body Einfo.Utils is
    procedure Init_Size_Align (Id : E) is
    begin
       pragma Assert (Ekind (Id) in Type_Kind | E_Void);
-      Set_Esize (Id, Uint_0);
-      Set_RM_Size (Id, Uint_0);
-      Set_Alignment (Id, Uint_0);
+      Init_Esize (Id);
+      Init_RM_Size (Id);
+      Init_Alignment (Id);
    end Init_Size_Align;
 
    ----------------------------------------------
@@ -509,9 +518,9 @@ package body Einfo.Utils is
    ----------------------------------------------
 
    function Known_Alignment                       (E : Entity_Id) return B is
+      Result : constant B := not Field_Is_Initial_Zero (E, F_Alignment);
    begin
-      return Alignment (E) /= Uint_0
-        and then Alignment (E) /= No_Uint;
+      return Result;
    end Known_Alignment;
 
    function Known_Component_Bit_Offset            (E : Entity_Id) return B is