ada: Improved checking of uses of package renamings

In some cases, the RM 8.5.1(3.1) legality rule about uses of renamings of
limited views of packages was implemented incorrectly, resulting in rejecting
legal uses.

gcc/ada/ChangeLog:

	* gen_il-fields.ads: add new Renames_Limited_View field.
	* gen_il-gen-gen_entities.adb: add Renames_Limited_View flag for
	packages.
	* einfo.ads: add comment documenting Renames_Limited_View flag.
	* sem_ch8.adb (Analyze_Package_Renaming): Set new Renames_Limited_View
	flag. Test new Renames_Limited_View flag instead of calling
	Has_Limited_With. If Has_Limited_With is True, that just means
	that somebody, sometime during this compilation needed to
	reference the limited view of the package; so that function
	returns True too often to be used here.
	(Find_Expanded_Name): Test new Renames_Limited_View flag instead of
	calling Has_Limited_With.

diff --git a/gcc/ada/einfo.ads b/gcc/ada/einfo.ads
index 1946e68b3c76a1c5ea9e6898d74dcdcd8cc58f1a..a7c0584d8da453447d80c508fad31f7e3f39ce3d 100644 (file)
--- a/gcc/ada/einfo.ads
+++ b/gcc/ada/einfo.ads
@@ -4247,6 +4247,15 @@ package Einfo is
 --       within an accept statement. For all remaining cases (discriminants,
 --       loop parameters) the field is Empty.
 
+--    Renames_Limited_View
+--       Defined in package entities. True for a package renaming if either
+--       a) the renamed package is not itself a renaming, and the renaming
+--          denotes a limited view of the renamed package (as seen at the
+--          point of the renaming declaration, as opposed to later on when
+--          the renaming is referenced); or
+--       b) the renamed package is itself a renaming and the
+--          Renames_Limited_View flag is True for the renamed package.
+
 --    Requires_Overriding
 --       Defined in all subprograms and entries. Set for subprograms that
 --       require overriding as defined by RM-2005-3.9.3(6/2). Note that this

diff --git a/gcc/ada/gen_il-fields.ads b/gcc/ada/gen_il-fields.ads
index c778f00856d4567d19d3bca2ba050a4c9bc6be27..fe2da80c548819893ba37d8b2ee848e085308f81 100644 (file)
--- a/gcc/ada/gen_il-fields.ads
+++ b/gcc/ada/gen_il-fields.ads
@@ -879,6 +879,7 @@ package Gen_IL.Fields is
       Relative_Deadline_Variable,
       Renamed_In_Spec,
       Renamed_Or_Alias, -- Shared among Alias, Renamed_Entity, Renamed_Object
+      Renames_Limited_View,
       Requires_Overriding,
       Return_Applies_To,
       Return_Present,

diff --git a/gcc/ada/gen_il-gen-gen_entities.adb b/gcc/ada/gen_il-gen-gen_entities.adb
index 8cf66b2611dfa834392a1e5655ec8f36e6dfbc6f..3df1f8e728443b43d28434d3d977273897764863 100644 (file)
--- a/gcc/ada/gen_il-gen-gen_entities.adb
+++ b/gcc/ada/gen_il-gen-gen_entities.adb
@@ -1281,6 +1281,7 @@ begin -- Gen_IL.Gen.Gen_Entities
         Sm (Related_Instance, Node_Id),
         Sm (Renamed_In_Spec, Flag),
         Sm (Renamed_Or_Alias, Node_Id),
+        Sm (Renames_Limited_View, Flag),
         Sm (Scope_Depth_Value, Unat),
         Sm (SPARK_Aux_Pragma, Node_Id),
         Sm (SPARK_Aux_Pragma_Inherited, Flag),

diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
index 533b62aef32126cfb6d75bb1333926ea5ff1c277..c6b8f6c5d7c8439f94b92df8b61522641392855d 100644 (file)
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -1665,8 +1665,7 @@ package body Sem_Ch8 is
          Set_Etype (New_P, Standard_Void_Type);
 
       elsif Present (Renamed_Entity (Old_P))
-        and then (From_Limited_With (Renamed_Entity (Old_P))
-                    or else Has_Limited_View (Renamed_Entity (Old_P)))
+        and then Renames_Limited_View (Old_P)
         and then not
           Unit_Is_Visible (Cunit (Get_Source_Unit (Renamed_Entity (Old_P))))
       then
@@ -1691,8 +1690,10 @@ package body Sem_Ch8 is
 
          if Present (Renamed_Entity (Old_P)) then
             Set_Renamed_Entity (New_P, Renamed_Entity (Old_P));
+            Set_Renames_Limited_View (New_P, Renames_Limited_View (Old_P));
          else
             Set_Renamed_Entity (New_P, Old_P);
+            Set_Renames_Limited_View (New_P, From_Limited_With (Old_P));
          end if;
 
          --  The package renaming declaration may become Ghost if it renames a
@@ -7077,7 +7078,7 @@ package body Sem_Ch8 is
               ("renaming of limited view of package & not usable in this"
                & " context (RM 8.5.3(3.1/2))", Prefix (N), P_Name);
 
-         elsif Has_Limited_View (P_Name)
+         elsif Renames_Limited_View (Entity (Prefix (N)))
            and then not Unit_Is_Visible (Cunit (Get_Source_Unit (P_Name)))
            and then not Is_Visible_Through_Renamings (P_Name)
          then