[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, 6 insertions, 2 deletions

diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index b09e20d..83ca31a 100644
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -4417,9 +4417,13 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
 	      const bool derived_p = Is_Derived_Type (gnat_entity);
 	      const Entity_Id gnat_parent
 		= derived_p ? Etype (Base_Type (gnat_entity)) : Empty;
+	      /* The following test for Known_Alignment preserves the old behavior,
+		 but is probably wrong. */
 	      const unsigned int inherited_align
 		= derived_p
-		  ? UI_To_Int (Alignment (gnat_parent)) * BITS_PER_UNIT
+		  ? (Known_Alignment (gnat_parent)
+		     ? UI_To_Int (Alignment (gnat_parent)) * BITS_PER_UNIT
+		     : 0)
 		  : POINTER_SIZE;
 	      const unsigned int align
 		= MAX (TYPE_ALIGN (gnu_type), inherited_align);
@@ -4724,7 +4728,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
 	   && Present (gnat_annotate_type))
     {
       if (!Known_Alignment (gnat_entity))
-	Set_Alignment (gnat_entity, Alignment (gnat_annotate_type));
+	Copy_Alignment (gnat_entity, gnat_annotate_type);
       if (!Known_Esize (gnat_entity))
 	Set_Esize (gnat_entity, Esize (gnat_annotate_type));
       if (!Known_RM_Size (gnat_entity))