[Ada] Add Ada 2022 Image and Put_Image support for tagged types

gcc/ada/

	* debug.adb: Remove comments about -gnatd_z switch.
	* exp_ch3.adb (Make_Predefined_Primitive_Specs): A one-line fix
	for a subtle bug that took some effort to debug. Append a new
	Put_Image procedure for a type extension even if it seems to
	already have one, just as is done for (for example) the
	streaming-related Read procedure.
	* exp_put_image.adb:
	(Build_Record_Put_Image_Procedure.Make_Component_Attributes): Do
	not treat _Parent component like just another component, for two
	reasons.  1. If the _parent component's type has a
	user-specified Put_Image procedure, then we want to generate a
	call to that procedure and then generate extension aggregate
	syntax.  2. Otherwise, we still don't want to see any mention of
	"_parent" in the generated image text.
	(Build_Record_Put_Image_Procedure.Make_Component_Name): Add
	assertion that we are not generating a reference to an "_parent"
	component.
	(Build_Record_Put_Image_Procedure): Add special treatment for
	null records.  Add call to Duplicate_Subexpr for image attribute
	prefix in order to help with expansion needed in the class-wide
	case (where the prefix is also referenced in the call to
	Wide_Wide_Expanded_Name) if evaluation of the prefix has side
	effects. Add new local helper function, Put_String_Exp.  Add
	support for case where prefix type is class-wide.
	(Enable_Put_Image, Preload_Root_Buffer_Type): Query Ada_Version
	> Ada_2022 instead of (indirectly) querying -gnatd_z switch.
	* freeze.adb (In_Expanded_Body): A one-line change to add
	TSS_Put_Image to the list of subprograms that have
	expander-created bodies.
	* rtsfind.ads: Add support for accessing
	Ada.Tags.Wide_Wide_Expanded_Name.
	* sem_ch3.ads, sem_ch3.adb: Delete Is_Null_Extension function,
	as part of moving it to Sem_Util.
	* sem_ch13.adb
	(Analyze_Put_Image_TSS_Definition.Has_Good_Profile): Improve
	diagnostic messages in cases where the result is going to be
	False and the Report parameter is True. Relax overly-restrictive
	checks in order to implement mode conformance.
	(Analyze_Stream_TSS_Definition.Has_Good_Profile): Add similar
	relaxation of parameter subtype checking for the Stream
	parameter of user-defined streaming subprograms.
	* sem_disp.adb (Check_Dispatching_Operation): A one-line
	change (and an accompanying comment change) to add TSS_Put_Image
	to the list of compiler-generated dispatching primitive
	operations.
	* sem_util.ads, sem_util.adb: Add Ignore_Privacy Boolean
	parameter to Is_Null_Record_Type function (typically the
	parameter will be False when the function is being used in the
	implementation of static semantics and True for dynamic
	semantics; the parameter might make a difference in the case of,
	for example, a private type that is implemented as a null record
	type).  Add related new routines Is_Null_Extension (formerly
	declared in Sem_Ch3), Is_Null_Extension_Of, and
	Is_Null_Record_Definition.

1 files changed, 22 insertions, 3 deletions

diff --git a/gcc/ada/sem_util.ads b/gcc/ada/sem_util.ads
index 10f1ba5..0894d03 100644
--- a/gcc/ada/sem_util.ads
+++ b/gcc/ada/sem_util.ads
@@ -2126,9 +2126,28 @@ package Sem_Util is
    --  assertion expression of pragma Default_Initial_Condition and if it does,
    --  the encapsulated expression is nontrivial.
 
-   function Is_Null_Record_Type (T : Entity_Id) return Boolean;
-   --  Determine whether T is declared with a null record definition or a
-   --  null component list.
+   function Is_Null_Extension
+    (T : Entity_Id; Ignore_Privacy : Boolean := False) return Boolean;
+   --  Given a tagged type, returns True if argument is a type extension
+   --  that introduces no new components (discriminant or nondiscriminant).
+   --  Ignore_Privacy should be True for use in implementing dynamic semantics.
+
+   function Is_Null_Extension_Of
+     (Descendant, Ancestor : Entity_Id) return Boolean;
+   --  Given two tagged types, the first a descendant of the second,
+   --  returns True if every component of Descendant is inherited
+   --  (directly or indirectly) from Ancestor. Privacy is ignored.
+
+   function Is_Null_Record_Definition (Record_Def : Node_Id) return Boolean;
+   --  Returns True for an N_Record_Definition node that has no user-defined
+   --  components (and no variant part).
+
+   function Is_Null_Record_Type
+     (T : Entity_Id; Ignore_Privacy : Boolean := False) return Boolean;
+   --  Determine whether T is declared with a null record definition, a
+   --  null component list, or as a type derived from a null record type
+   --  (with a null extension if tagged). Returns True for interface types,
+   --  False for discriminated types.
 
    function Is_Object_Image (Prefix : Node_Id) return Boolean;
    --  Returns True if an 'Img, 'Image, 'Wide_Image, or 'Wide_Wide_Image