ada: Small cleanup in processing of primitive operations

The processing of primitive operations is now always uniform for tagged and
untagged types, but the code contains left-overs from the time where it was
specific to tagged types, in particular for the handling of subtypes.

gcc/ada/

	* einfo.ads (Direct_Primitive_Operations): Mention concurrent types
	as well as GNAT extensions instead of implementation details.
	(Primitive_Operations): Document that Direct_Primitive_Operations is
	also used for concurrent types as a fallback.
	* einfo-utils.adb (Primitive_Operations): Tweak formatting.
	* exp_util.ads (Find_Prim_Op): Adjust description.
	* exp_util.adb (Make_Subtype_From_Expr): In the private case with
	unknown discriminants, always copy Direct_Primitive_Operations and
	do not overwrite the Class_Wide_Type of the expression's base type.
	* sem_ch3.adb (Analyze_Incomplete_Type_Decl): Tweak comment.
	(Analyze_Subtype_Declaration): Remove older and now dead calls to
	Set_Direct_Primitive_Operations.  Tweak comment.
	(Build_Derived_Private_Type): Likewise.
	(Build_Derived_Record_Type): Likewise.
	(Build_Discriminated_Subtype): Set Direct_Primitive_Operations in
	all cases instead of just for tagged types.
	(Complete_Private_Subtype): Likewise.
	(Derived_Type_Declaration): Tweak comment.
	* sem_ch4.ads (Try_Object_Operation): Adjust description.

1 files changed, 18 insertions, 16 deletions

diff --git a/gcc/ada/einfo.ads b/gcc/ada/einfo.ads
index dd95ea0..de17531 100644
--- a/gcc/ada/einfo.ads
+++ b/gcc/ada/einfo.ads
@@ -932,18 +932,17 @@ package Einfo is
 --       subtypes. Contains the Digits value specified in the declaration.
 
 --    Direct_Primitive_Operations
---       Defined in tagged types and subtypes (including synchronized types),
---       in tagged private types, and in tagged incomplete types. Moreover, it
---       is also defined for untagged types, both when Extensions_Allowed is
---       True (-gnatX) to support the extension feature of prefixed calls for
---       untagged types, and when Extensions_Allowed is False to get better
---       error messages. This field is an element list of entities for
---       primitive operations of the type. For incomplete types the list is
---       always empty. In order to follow the C++ ABI, entities of primitives
---       that come from source must be stored in this list in the order of
---       their occurrence in the sources. When expansion is disabled, the
---       corresponding record type of a synchronized type is not constructed.
---       In that case, such types carry this attribute directly.
+--       Defined in concurrent types, tagged record types and subtypes, tagged
+--       private types, and tagged incomplete types. Moreover, it is also
+--       defined in untagged types, both when GNAT extensions are allowed, to
+--       support prefixed calls for untagged types, and when GNAT extensions
+--       are not allowed, to give better error messages. Set to a list of
+--       entities for primitive operations of the type. For incomplete types
+--       the list is always empty. In order to follow the C++ ABI, entities of
+--       primitives that come from source must be stored in this list in the
+--       order of their occurrence in the sources. When expansion is disabled,
+--       the corresponding record type of concurrent types is not constructed;
+--       in this case, such types carry this attribute directly.
 
 --    Directly_Designated_Type
 --       Defined in access types. This field points to the type that is
@@ -4066,10 +4065,13 @@ package Einfo is
 
 --    Primitive_Operations (synthesized)
 --       Defined in concurrent types, tagged record types and subtypes, tagged
---       private types and tagged incomplete types. For concurrent types whose
---       Corresponding_Record_Type (CRT) is available, returns the list of
---       Direct_Primitive_Operations of its CRT; otherwise returns No_Elist.
---       For all the other types returns the Direct_Primitive_Operations.
+--       private types, and tagged incomplete types. Moreover, it is also
+--       defined in untagged types, both when GNAT extensions are allowed, to
+--       support prefixed calls for untagged types, and when GNAT extensions
+--       are not allowed, to give better error messages.  For concurrent types
+--       whose Corresponding_Record_Type (CRT) is available, returns the list
+--       of Direct_Primitive_Operations of this CRT. In all the other cases,
+--       returns the list of Direct_Primitive_Operations.
 
 --    Prival
 --       Defined in private components of protected types. Refers to the entity