[Ada] Implementation of Preelaborable_Initialization attribute for AI12-0409

gcc/ada/

	* exp_attr.adb (Expand_N_Attribute_Reference): Fold
	Preelaborable_Initialization attribute in cases where it hasn't
	been folded by the analyzer.
	* exp_disp.adb (Original_View_In_Visible_Part): This function is
	removed and moved to sem_util.adb.
	* sem_attr.adb (Attribute_22): Add
	Attribute_Preelaborable_Initialization as an Ada 2022 attribute.
	(Analyze_Attribute, Attribute_Preelaborable_Initialization):
	Check that the prefix of the attribute is either a formal
	private or derived type, or a composite type declared within the
	visible part of a package or generic package.
	(Eval_Attribute): Perform folding of
	Preelaborable_Initialization attribute based on
	Has_Preelaborable_Initialization applied to the prefix type.
	* sem_ch3.adb (Resolve_Aspects): Add specialized code for
	Preelaborable_Initialization used at the end of a package
	visible part for setting Known_To_Have_Preelab_Init on types
	that are specified with True or that have a conjunction of one
	or more P_I attributes applied to formal types.
	* sem_ch7.adb (Analyze_Package_Specification): On call to
	Has_Preelaborable_Initialization, pass True for new formal
	Formal_Types_Have_Preelab_Init, so that error checking treats
	subcomponents that are declared within types in generics as
	having preelaborable initialization when the subcomponents are
	of formal types.
	* sem_ch13.adb (Analyze_Aspects_At_Freeze_Point): Add test for
	P_I to prevent calling Make_Pragma_From_Boolean_Aspect, since
	this aspect is handled specially and the
	Known_To_Have_Preelab_Init flag will get set on types that have
	the aspect by other means.
	(Analyze_Aspect_Specifications.Analyze_One_Aspect): Add test for
	Aspect_Preelaborable_Initialization for allowing the aspect to
	be specified on formal type declarations.
	(Is_Operational_Item): Treat Attribute_Put_Image as an
	operational attribute.  The need for this was encountered while
	working on these changes.
	* sem_util.ads (Has_Preelaborable_Initialization): Add
	Formal_Types_Have_Preelab_Init as a new formal parameter that
	defaults to False.
	(Is_Conjunction_Of_Formal_Preelab_Init_Attributes): New
	function.
	(Original_View_In_Visible_Part): Moved here from exp_disp.adb,
	so it can be called by Analyze_Attribute.
	* sem_util.adb (Has_Preelaborable_Initialization): Return True
	for formal private and derived types when new formal
	Formal_Types_Have_Preelab_Init is True, and pass along the
	Formal_Types_Have_Preelab_Init flag in the array component case.
	(Check_Components): Pass along Formal_Types_Have_Preelab_Init
	flag on call to Has_Preelaborable_Initialization.
	(Is_Conjunction_Of_Formal_Preelab_Init_Attributes): New function
	that returns True when passed an expression that includes one or
	more attributes for Preelaborable_Initialization applied to
	prefixes that denote formal types.
	(Is_Formal_Preelab_Init_Attribute): New utility function nested
	within Is_Conjunction_Of_Formal_Preelab_Init_Attributes that
	determines whether a node is a P_I attribute applied to a
	generic formal type.
	(Original_View_In_Visible_Part): Moved here from exp_util.adb,
	so it can be called by Analyze_Attribute.
	* snames.ads-tmpl: Add note near the start of spec giving
	details about what needs to be done when adding a name that
	corresponds to both an attribute and a pragma.  Delete existing
	occurrence of Name_Preelaborable_Initialization, and add a note
	comment in the list of Name_* constants at that place,
	indicating that it's included in type Pragma_Id, etc., echoing
	other such comments for names that are both an attribute and a
	pragma.  Insert Name_Preelaborable_Initialization in the
	alphabetized set of Name_* constants corresponding to
	attributes (between First_Attribute_Name and
	Last_Attribute_Name).
	(type Attribute_Id): Add new literal
	Attribute_Preelaborable_Initialization.
	(type Pragma_Id): Move Pragma_Preelaborable_Initialization from
	its current position to the end of the type, in the special set
	of pragma literals that have corresponding atttributes. Add to
	accompanying comment, indicating that functions Get_Pragma_Id
	and Is_Pragma_Name need to be updated when adding a pragma
	literal to the special set.
	* snames.adb-tmpl (Get_Pragma_Id): Add case alternative for
	Pragma_Preelaborable_Initialization.
	(Is_Pragma_Name): Add test for
	Name_Preelaborable_Initialization.

1 files changed, 7 insertions, 2 deletions

diff --git a/gcc/ada/sem_ch7.adb b/gcc/ada/sem_ch7.adb
index f30a9aa..30eade2 100644
--- a/gcc/ada/sem_ch7.adb
+++ b/gcc/ada/sem_ch7.adb
@@ -1768,11 +1768,16 @@ package body Sem_Ch7 is
          end if;
 
          --  Check preelaborable initialization for full type completing a
-         --  private type for which pragma Preelaborable_Initialization given.
+         --  private type when aspect Preelaborable_Initialization is True.
+         --  We pass True for the parameter Formal_Types_Have_Preelab_Init
+         --  to take into account the rule that presumes that subcomponents
+         --  of generic formal types mentioned in the type's P_I aspect have
+         --  preelaborable initialization (see RM 10.2.1(11.8/5)).
 
          if Is_Type (E)
            and then Must_Have_Preelab_Init (E)
-           and then not Has_Preelaborable_Initialization (E)
+           and then not Has_Preelaborable_Initialization
+                          (E, Formal_Types_Have_Preelab_Init => True)
          then
             Error_Msg_N
               ("full view of & does not have preelaborable initialization", E);