[multiple changes]

2013-01-03  Thomas Quinot  <quinot@adacore.com>

	* sem_ch7.adb, sem_ch10.adb, einfo.adb, einfo.ads, sem_ch12.adb,
	rtsfind.adb, sem_elab.adb, sem_ch4.adb, sem_ch8.adb
	(Einfo.Is_Visible_Child_Unit, Einfo.Set_Is_Visible_Child_Unit):
	Rename to Is_Visible_Lib_Unit, Set_Is_Visible_Lib_Unit, and
	update spec accordingly (now also applies to root library units).
	(Sem_Ch10.Analyze_Subunit.Analyze_Subunit_Context): Toggle above flag
	on root library units, not only child units.
	(Sem_Ch10.Install[_Limited]_Withed_Unit): Same.
	(Sem_Ch10.Remove_Unit_From_Visibility): Reset Is_Visible_Lib_Unit
	even for root library units.
	(Sem_Ch8.Find_Expanded_Name): A selected component form whose prefix is
	Standard is an expanded name for a root library unit.

2013-01-03  Thomas Quinot  <quinot@adacore.com>

	* exp_ch3.adb: Minor reformatting.

2013-01-03  Olivier Hainque  <hainque@adacore.com>

	* tracebak.c: Reinstate changes to support ppc-lynx178.

2013-01-03  Ed Schonberg  <schonberg@adacore.com>

	* atree.ads: Minor reformatting and documentation enhancement.

From-SVN: r194845

13 files changed, 123 insertions, 63 deletions

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index ad2c268..ce761e1 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,30 @@
+2013-01-03  Thomas Quinot  <quinot@adacore.com>
+
+	* sem_ch7.adb, sem_ch10.adb, einfo.adb, einfo.ads, sem_ch12.adb,
+	rtsfind.adb, sem_elab.adb, sem_ch4.adb, sem_ch8.adb
+	(Einfo.Is_Visible_Child_Unit, Einfo.Set_Is_Visible_Child_Unit):
+	Rename to Is_Visible_Lib_Unit, Set_Is_Visible_Lib_Unit, and
+	update spec accordingly (now also applies to root library units).
+	(Sem_Ch10.Analyze_Subunit.Analyze_Subunit_Context): Toggle above flag
+	on root library units, not only child units.
+	(Sem_Ch10.Install[_Limited]_Withed_Unit): Same.
+	(Sem_Ch10.Remove_Unit_From_Visibility): Reset Is_Visible_Lib_Unit
+	even for root library units.
+	(Sem_Ch8.Find_Expanded_Name): A selected component form whose prefix is
+	Standard is an expanded name for a root library unit.
+
+2013-01-03  Thomas Quinot  <quinot@adacore.com>
+
+	* exp_ch3.adb: Minor reformatting.
+
+2013-01-03  Olivier Hainque  <hainque@adacore.com>
+
+	* tracebak.c: Reinstate changes to support ppc-lynx178.
+
+2013-01-03  Ed Schonberg  <schonberg@adacore.com>
+
+	* atree.ads: Minor reformatting and documentation enhancement.
+
 2013-01-03  Ed Schonberg  <schonberg@adacore.com>
 
 	* exp_ch3.adb (Expand_N_Object_Declaration): If the object has
diff --git a/gcc/ada/atree.ads b/gcc/ada/atree.ads
index d503dc2..2b295ba 100644
--- a/gcc/ada/atree.ads
+++ b/gcc/ada/atree.ads
@@ -508,7 +508,9 @@ package Atree is
    --  entities point correctly to their original parents. The effect is thus
    --  to leave the tree completely unchanged in structure, except that the
    --  entity ID values of the two entities are interchanged. Neither of the
-   --  two entities may be list members.
+   --  two entities may be list members. Note that entities appear on two
+   --  semantic chains: Homonym and Next_Entity: the corresponding links must
+   --  be adjusted by the caller, according to context.
 
    function Extend_Node (Node : Node_Id) return Entity_Id;
    --  This function returns a copy of its input node with an extension added.
diff --git a/gcc/ada/einfo.adb b/gcc/ada/einfo.adb
index 89cd7826..4f57731 100644
--- a/gcc/ada/einfo.adb
+++ b/gcc/ada/einfo.adb
@@ -375,7 +375,7 @@ package body Einfo is
    --    No_Return                       Flag113
    --    Delay_Cleanups                  Flag114
    --    Never_Set_In_Source             Flag115
-   --    Is_Visible_Child_Unit           Flag116
+   --    Is_Visible_Lib_Unit             Flag116
    --    Is_Unchecked_Union              Flag117
    --    Is_For_Access_Subtype           Flag118
    --    Has_Convention_Pragma           Flag119
@@ -2175,11 +2175,10 @@ package body Einfo is
       return Flag127 (Id);
    end Is_Valued_Procedure;
 
-   function Is_Visible_Child_Unit (Id : E) return B is
+   function Is_Visible_Lib_Unit (Id : E) return B is
    begin
-      pragma Assert (Is_Child_Unit (Id));
       return Flag116 (Id);
-   end Is_Visible_Child_Unit;
+   end Is_Visible_Lib_Unit;
 
    function Is_Visible_Formal (Id : E) return B is
    begin
@@ -4736,11 +4735,10 @@ package body Einfo is
       Set_Flag127 (Id, V);
    end Set_Is_Valued_Procedure;
 
-   procedure Set_Is_Visible_Child_Unit (Id : E; V : B := True) is
+   procedure Set_Is_Visible_Lib_Unit (Id : E; V : B := True) is
    begin
-      pragma Assert (Is_Child_Unit (Id));
       Set_Flag116 (Id, V);
-   end Set_Is_Visible_Child_Unit;
+   end Set_Is_Visible_Lib_Unit;
 
    procedure Set_Is_Visible_Formal (Id : E; V : B := True) is
    begin
@@ -7602,7 +7600,7 @@ package body Einfo is
       W ("Is_Unsigned_Type",                Flag144 (Id));
       W ("Is_VMS_Exception",                Flag133 (Id));
       W ("Is_Valued_Procedure",             Flag127 (Id));
-      W ("Is_Visible_Child_Unit",           Flag116 (Id));
+      W ("Is_Visible_Lib_Unit",             Flag116 (Id));
       W ("Is_Visible_Formal",               Flag206 (Id));
       W ("Is_Volatile",                     Flag16  (Id));
       W ("Itype_Printed",                   Flag202 (Id));
diff --git a/gcc/ada/einfo.ads b/gcc/ada/einfo.ads
index 1b412e5..35400cf 100644
--- a/gcc/ada/einfo.ads
+++ b/gcc/ada/einfo.ads
@@ -2856,11 +2856,11 @@ package Einfo is
 --       Defined in procedure entities. Set if an Import_Valued_Procedure
 --       or Export_Valued_Procedure pragma applies to the procedure entity.
 
---    Is_Visible_Child_Unit (Flag116)
---       Defined in compilation units that are child units. Once compiled,
---       child units remain chained to the entities in the parent unit, and
---       a separate flag must be used to indicate whether the names are
---       visible by selected notation, or not.
+--    Is_Visible_Lib_Unit (Flag116)
+--       Defined in all (root or child) library unit entities. Once compiled,
+--       library units remain chained to the entities in the parent scope, and
+--       a separate flag must be used to indicate whether the names are visible
+--       by selected notation, or not.
 
 --    Is_Visible_Formal (Flag206)
 --       Defined in all entities. Set True for instances of the formals of a
@@ -5310,7 +5310,7 @@ package Einfo is
    --    Is_Private_Primitive                (Flag245)  (non-generic case only)
    --    Is_Pure                             (Flag44)
    --    Is_Thunk                            (Flag225)
-   --    Is_Visible_Child_Unit               (Flag116)
+   --    Is_Visible_Lib_Unit                 (Flag116)
    --    Needs_No_Actuals                    (Flag22)
    --    Requires_Overriding                 (Flag213)  (non-generic case only)
    --    Return_Present                      (Flag54)
@@ -5490,7 +5490,7 @@ package Einfo is
    --    In_Use                              (Flag8)
    --    Is_Instantiated                     (Flag126)
    --    Is_Private_Descendant               (Flag53)
-   --    Is_Visible_Child_Unit               (Flag116)
+   --    Is_Visible_Lib_Unit                 (Flag116)
    --    Renamed_In_Spec                     (Flag231)  (non-generic case only)
    --    Static_Elaboration_Desired          (Flag77)   (non-generic case only)
    --    Is_Wrapper_Package                  (synth)    (non-generic case only)
@@ -5580,7 +5580,7 @@ package Einfo is
    --    Is_Pure                             (Flag44)
    --    Is_Thunk                            (Flag225)
    --    Is_Valued_Procedure                 (Flag127)
-   --    Is_Visible_Child_Unit               (Flag116)
+   --    Is_Visible_Lib_Unit                 (Flag116)
    --    Needs_No_Actuals                    (Flag22)
    --    No_Return                           (Flag113)
    --    Requires_Overriding                 (Flag213)  (non-generic case only)
@@ -6310,7 +6310,7 @@ package Einfo is
    function Is_Unsigned_Type                    (Id : E) return B;
    function Is_VMS_Exception                    (Id : E) return B;
    function Is_Valued_Procedure                 (Id : E) return B;
-   function Is_Visible_Child_Unit               (Id : E) return B;
+   function Is_Visible_Lib_Unit                 (Id : E) return B;
    function Is_Visible_Formal                   (Id : E) return B;
    function Is_Volatile                         (Id : E) return B;
    function Itype_Printed                       (Id : E) return B;
@@ -6908,7 +6908,7 @@ package Einfo is
    procedure Set_Is_Unsigned_Type                (Id : E; V : B := True);
    procedure Set_Is_VMS_Exception                (Id : E; V : B := True);
    procedure Set_Is_Valued_Procedure             (Id : E; V : B := True);
-   procedure Set_Is_Visible_Child_Unit           (Id : E; V : B := True);
+   procedure Set_Is_Visible_Lib_Unit             (Id : E; V : B := True);
    procedure Set_Is_Visible_Formal               (Id : E; V : B := True);
    procedure Set_Is_Volatile                     (Id : E; V : B := True);
    procedure Set_Itype_Printed                   (Id : E; V : B := True);
@@ -7629,7 +7629,7 @@ package Einfo is
    pragma Inline (Is_Unsigned_Type);
    pragma Inline (Is_VMS_Exception);
    pragma Inline (Is_Valued_Procedure);
-   pragma Inline (Is_Visible_Child_Unit);
+   pragma Inline (Is_Visible_Lib_Unit);
    pragma Inline (Is_Visible_Formal);
    pragma Inline (Itype_Printed);
    pragma Inline (Kill_Elaboration_Checks);
@@ -8035,7 +8035,7 @@ package Einfo is
    pragma Inline (Set_Is_Unsigned_Type);
    pragma Inline (Set_Is_VMS_Exception);
    pragma Inline (Set_Is_Valued_Procedure);
-   pragma Inline (Set_Is_Visible_Child_Unit);
+   pragma Inline (Set_Is_Visible_Lib_Unit);
    pragma Inline (Set_Is_Visible_Formal);
    pragma Inline (Set_Is_Volatile);
    pragma Inline (Set_Itype_Printed);
diff --git a/gcc/ada/exp_ch3.adb b/gcc/ada/exp_ch3.adb
index f33d0f7..83d0c00 100644
--- a/gcc/ada/exp_ch3.adb
+++ b/gcc/ada/exp_ch3.adb
@@ -5315,6 +5315,17 @@ package body Exp_Ch3 is
                       Subtype_Mark        => New_Occurrence_Of (Typ, Loc),
                       Name => Convert_Tag_To_Interface (Typ, Tag_Comp)));
 
+                  --  If the original entity comes from source, then mark the
+                  --  new entity as needing debug information, even though it's
+                  --  defined by a generated renaming that does not come from
+                  --  source, so that Materialize_Entity will be set on the
+                  --  entity when Debug_Renaming_Declaration is called during
+                  --  analysis.
+
+                  if Comes_From_Source (Def_Id) then
+                     Set_Debug_Info_Needed (Defining_Identifier (N));
+                  end if;
+
                   Analyze (N, Suppress => All_Checks);
 
                   --  Replace internal identifier of rewritten node by the
@@ -5328,7 +5339,7 @@ package body Exp_Ch3 is
                   --  which may be a constant. Preserve entity chain because
                   --  itypes may have been generated already, and the full
                   --  chain must be preserved for final freezing. Finally,
-                  --  Preserve Comes_From_Source setting, so that debugging
+                  --  preserve Comes_From_Source setting, so that debugging
                   --  and cross-referencing information is properly kept.
 
                   declare
@@ -5340,9 +5351,11 @@ package body Exp_Ch3 is
                   begin
                      Set_Next_Entity (New_Id, Next_Entity (Def_Id));
                      Set_Next_Entity (Def_Id, Next_Temp);
-                     Set_Chars (Defining_Identifier (N), Chars (Def_Id));
+
+                     Set_Chars   (Defining_Identifier (N), Chars   (Def_Id));
                      Set_Homonym (Defining_Identifier (N), Homonym (Def_Id));
-                     Set_Ekind (Defining_Identifier (N), Ekind (Def_Id));
+                     Set_Ekind   (Defining_Identifier (N), Ekind   (Def_Id));
+
                      Set_Comes_From_Source (Def_Id, False);
                      Exchange_Entities (Defining_Identifier (N), Def_Id);
                      Set_Comes_From_Source (Def_Id, S_Flag);
diff --git a/gcc/ada/rtsfind.adb b/gcc/ada/rtsfind.adb
index 3b3e768..ac662f8 100644
--- a/gcc/ada/rtsfind.adb
+++ b/gcc/ada/rtsfind.adb
@@ -1466,7 +1466,7 @@ package body Rtsfind is
                end if;
 
                Load_RTU (To_Load, Use_Setting => In_Use (Cunit_Entity (U)));
-               Set_Is_Visible_Child_Unit (RT_Unit_Table (To_Load).Entity);
+               Set_Is_Visible_Lib_Unit (RT_Unit_Table (To_Load).Entity);
 
                --  Prevent creation of an implicit 'with' from (for example)
                --  Ada.Wide_Text_IO.Integer_IO to Ada.Text_IO.Integer_IO,
diff --git a/gcc/ada/sem_ch10.adb b/gcc/ada/sem_ch10.adb
index b55d064..0fd690a 100644
--- a/gcc/ada/sem_ch10.adb
+++ b/gcc/ada/sem_ch10.adb
@@ -2040,9 +2040,15 @@ package body Sem_Ch10 is
                      end if;
 
                      Unit_Name := Entity (Name (Item));
-                     while Is_Child_Unit (Unit_Name) loop
-                        Set_Is_Visible_Child_Unit (Unit_Name);
+                     loop
+                        Set_Is_Visible_Lib_Unit (Unit_Name);
+                        exit when Scope (Unit_Name) = Standard_Standard;
                         Unit_Name := Scope (Unit_Name);
+
+                        if No (Unit_Name) then
+                           Check_Error_Detected;
+                           return;
+                        end if;
                      end loop;
 
                      if not Is_Immediately_Visible (Unit_Name) then
@@ -2083,8 +2089,9 @@ package body Sem_Ch10 is
               and then not Error_Posted (Item)
             then
                Unit_Name := Entity (Name (Item));
-               while Is_Child_Unit (Unit_Name) loop
-                  Set_Is_Visible_Child_Unit (Unit_Name, False);
+               loop
+                  Set_Is_Visible_Lib_Unit (Unit_Name, False);
+                  exit when Scope (Unit_Name) = Standard_Standard;
                   Unit_Name := Scope (Unit_Name);
                end loop;
 
@@ -2131,7 +2138,7 @@ package body Sem_Ch10 is
          E := First_Entity (Current_Scope);
          while Present (E) loop
             if not Is_Child_Unit (E)
-              or else Is_Visible_Child_Unit (E)
+              or else Is_Visible_Lib_Unit (E)
             then
                Set_Is_Immediately_Visible (E);
             end if;
@@ -2296,11 +2303,9 @@ package body Sem_Ch10 is
             C : Entity_Id;
          begin
             C := Current_Scope;
-            while Present (C)
-              and then Is_Child_Unit (C)
-            loop
+            while Present (C) and then C /= Standard_Standard loop
                Set_Is_Immediately_Visible (C);
-               Set_Is_Visible_Child_Unit (C);
+               Set_Is_Visible_Lib_Unit (C);
                C := Scope (C);
             end loop;
          end;
@@ -4210,7 +4215,7 @@ package body Sem_Ch10 is
                   end In_Context;
 
                begin
-                  Set_Is_Visible_Child_Unit (Id, In_Context);
+                  Set_Is_Visible_Lib_Unit (Id, In_Context);
                end;
             end if;
          end if;
@@ -4788,7 +4793,7 @@ package body Sem_Ch10 is
       if Analyzed (P_Unit)
         and then
           (Is_Immediately_Visible (P)
-            or else (Is_Child_Package and then Is_Visible_Child_Unit (P)))
+            or else (Is_Child_Package and then Is_Visible_Lib_Unit (P)))
       then
 
          --  The presence of both the limited and the analyzed nonlimited view
@@ -4852,10 +4857,10 @@ package body Sem_Ch10 is
             Set_Ekind (P, E_Package);
             Set_Etype (P, Standard_Void_Type);
             Set_Scope (P, Standard_Standard);
+            Set_Is_Visible_Lib_Unit (P);
 
             if Is_Child_Package then
                Set_Is_Child_Unit (P);
-               Set_Is_Visible_Child_Unit (P);
                Set_Scope (P, Defining_Entity (Unit (Parent_Spec (P_Unit))));
             end if;
 
@@ -5101,7 +5106,7 @@ package body Sem_Ch10 is
             Error_Msg_N
               ("instantiation depends on itself", Name (With_Clause));
 
-         elsif not Is_Visible_Child_Unit (Uname) then
+         elsif not Is_Visible_Lib_Unit (Uname) then
 
             --  Abandon processing in case of previous errors
 
@@ -5110,7 +5115,7 @@ package body Sem_Ch10 is
                return;
             end if;
 
-            Set_Is_Visible_Child_Unit (Uname);
+            Set_Is_Visible_Lib_Unit (Uname);
 
             --  If the child unit appears in the context of its parent, it is
             --  immediately visible.
@@ -5125,7 +5130,7 @@ package body Sem_Ch10 is
                --  Set flag as well on the visible entity that denotes the
                --  instance, which renames the current one.
 
-               Set_Is_Visible_Child_Unit
+               Set_Is_Visible_Lib_Unit
                  (Related_Instance
                    (Defining_Entity (Unit (Library_Unit (With_Clause)))));
             end if;
@@ -5141,6 +5146,7 @@ package body Sem_Ch10 is
          end if;
 
       elsif not Is_Immediately_Visible (Uname) then
+         Set_Is_Visible_Lib_Unit (Uname);
          if not Private_Present (With_Clause)
            or else Private_With_OK
          then
@@ -5167,7 +5173,7 @@ package body Sem_Ch10 is
       --  not apply the check to the Standard package itself.
 
       if Is_Child_Unit (Uname)
-        and then Is_Visible_Child_Unit (Uname)
+        and then Is_Visible_Lib_Unit (Uname)
         and then Ada_Version >= Ada_2005
       then
          declare
@@ -5185,7 +5191,7 @@ package body Sem_Ch10 is
                Decl2  := Unit_Declaration_Node (P2);
 
                if Is_Child_Unit (U2)
-                 and then Is_Visible_Child_Unit (U2)
+                 and then Is_Visible_Lib_Unit (U2)
                then
                   if Is_Generic_Instance (P)
                     and then Nkind (Decl1) = N_Package_Declaration
@@ -6220,8 +6226,6 @@ package body Sem_Ch10 is
    ---------------------------------
 
    procedure Remove_Unit_From_Visibility (Unit_Name : Entity_Id) is
-      P : constant Entity_Id := Scope (Unit_Name);
-
    begin
       if Debug_Flag_I then
          Write_Str ("remove unit ");
@@ -6230,10 +6234,7 @@ package body Sem_Ch10 is
          Write_Eol;
       end if;
 
-      if P /= Standard_Standard then
-         Set_Is_Visible_Child_Unit (Unit_Name, False);
-      end if;
-
+      Set_Is_Visible_Lib_Unit        (Unit_Name, False);
       Set_Is_Potentially_Use_Visible (Unit_Name, False);
       Set_Is_Immediately_Visible     (Unit_Name, False);
 
diff --git a/gcc/ada/sem_ch12.adb b/gcc/ada/sem_ch12.adb
index ee88332..040d624 100644
--- a/gcc/ada/sem_ch12.adb
+++ b/gcc/ada/sem_ch12.adb
@@ -5719,7 +5719,7 @@ package body Sem_Ch12 is
                  and then Is_Child_Unit (E)
                then
                   if Is_Child_Unit (E)
-                    and then not Is_Visible_Child_Unit (E)
+                    and then not Is_Visible_Lib_Unit (E)
                   then
                      Error_Msg_NE
                        ("generic child unit& is not visible", Gen_Id, E);
diff --git a/gcc/ada/sem_ch4.adb b/gcc/ada/sem_ch4.adb
index 14e7f93..9442760 100644
--- a/gcc/ada/sem_ch4.adb
+++ b/gcc/ada/sem_ch4.adb
@@ -1765,7 +1765,7 @@ package body Sem_Ch4 is
                    (Is_Immediately_Visible (Scope (DT))
                      or else
                        (Is_Child_Unit (Scope (DT))
-                          and then Is_Visible_Child_Unit (Scope (DT))))
+                          and then Is_Visible_Lib_Unit (Scope (DT))))
                then
                   Set_Etype (N, Available_View (DT));
 
@@ -6320,7 +6320,7 @@ package body Sem_Ch4 is
           (Is_Immediately_Visible (Scope (Typ))
             or else
               (Is_Child_Unit (Scope (Typ))
-                 and then Is_Visible_Child_Unit (Scope (Typ))))
+                 and then Is_Visible_Lib_Unit (Scope (Typ))))
       then
          return Available_View (Typ);
       else
diff --git a/gcc/ada/sem_ch7.adb b/gcc/ada/sem_ch7.adb
index b81f575..dd1e1d4 100644
--- a/gcc/ada/sem_ch7.adb
+++ b/gcc/ada/sem_ch7.adb
@@ -2253,7 +2253,7 @@ package body Sem_Ch7 is
 
                if Is_Child_Unit (Id) then
                   Set_Is_Potentially_Use_Visible
-                    (Id, Is_Visible_Child_Unit (Id));
+                    (Id, Is_Visible_Lib_Unit (Id));
                else
                   Set_Is_Potentially_Use_Visible (Id);
                end if;
diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
index 50758e3..0a046de 100644
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -5143,8 +5143,8 @@ package body Sem_Ch8 is
             end if;
 
             if Is_New_Candidate then
-               if Is_Child_Unit (Id) then
-                  exit when Is_Visible_Child_Unit (Id)
+               if Is_Child_Unit (Id) or else P_Name = Standard_Standard then
+                  exit when Is_Visible_Lib_Unit (Id)
                     or else Is_Immediately_Visible (Id);
 
                else
@@ -5334,7 +5334,7 @@ package body Sem_Ch8 is
                     and then Is_Compilation_Unit (Homonym (P_Name))
                     and then
                      (Is_Immediately_Visible (Homonym (P_Name))
-                        or else Is_Visible_Child_Unit (Homonym (P_Name)))
+                        or else Is_Visible_Lib_Unit (Homonym (P_Name)))
                   then
                      declare
                         H : constant Entity_Id := Homonym (P_Name);
@@ -7685,7 +7685,7 @@ package body Sem_Ch8 is
                if Is_Child_Unit (E) then
                   if not From_With_Type (E) then
                      Set_Is_Immediately_Visible (E,
-                       Is_Visible_Child_Unit (E) or else In_Open_Scopes (E));
+                       Is_Visible_Lib_Unit (E) or else In_Open_Scopes (E));
 
                   else
                      pragma Assert
@@ -7718,7 +7718,7 @@ package body Sem_Ch8 is
                while Present (E) loop
                   if Is_Child_Unit (E) then
                      Set_Is_Immediately_Visible (E,
-                       Is_Visible_Child_Unit (E) or else In_Open_Scopes (E));
+                       Is_Visible_Lib_Unit (E) or else In_Open_Scopes (E));
                   end if;
 
                   Next_Entity (E);
@@ -8030,7 +8030,7 @@ package body Sem_Ch8 is
 
          if not Is_Hidden (Id)
            and then ((not Is_Child_Unit (Id))
-                       or else Is_Visible_Child_Unit (Id))
+                       or else Is_Visible_Lib_Unit (Id))
          then
             Set_Is_Potentially_Use_Visible (Id);
 
@@ -8050,7 +8050,7 @@ package body Sem_Ch8 is
 
       while Present (Id) loop
          if Is_Child_Unit (Id)
-           and then Is_Visible_Child_Unit (Id)
+           and then Is_Visible_Lib_Unit (Id)
          then
             Set_Is_Potentially_Use_Visible (Id);
          end if;
diff --git a/gcc/ada/sem_elab.adb b/gcc/ada/sem_elab.adb
index 125caef..4c86ce3 100644
--- a/gcc/ada/sem_elab.adb
+++ b/gcc/ada/sem_elab.adb
@@ -2551,7 +2551,7 @@ package body Sem_Elab is
       --  visible, and we can set the elaboration flag.
 
       if Is_Immediately_Visible (Scop)
-        or else (Is_Child_Unit (Scop) and then Is_Visible_Child_Unit (Scop))
+        or else (Is_Child_Unit (Scop) and then Is_Visible_Lib_Unit (Scop))
       then
          Activate_Elaborate_All_Desirable (Call, Scop);
          Set_Suppress_Elaboration_Warnings (Scop, True);
diff --git a/gcc/ada/tracebak.c b/gcc/ada/tracebak.c
index 2c8335d..123df59 100644
--- a/gcc/ada/tracebak.c
+++ b/gcc/ada/tracebak.c
@@ -35,6 +35,7 @@
    PowerPC/AiX
    PowerPC/Darwin
    PowerPC/VxWorks
+   PowerPC/LynxOS-178
    SPARC/Solaris
    i386/GNU/Linux
    i386/Solaris
@@ -287,9 +288,10 @@ __gnat_backtrace (void **array,
 #error Unhandled darwin architecture.
 #endif
 
-/*------------------------ PPC AIX/Older Darwin -------------------------*/
+/*---------------------- PPC AIX/PPC Lynx 178/Older Darwin ------------------*/
 #elif ((defined (_POWER) && defined (_AIX)) || \
-(defined (__ppc__) && defined (__APPLE__)))
+       (defined (__powerpc__) && defined (__Lynx__) && !defined(__ELF__)) || \
+       (defined (__ppc__) && defined (__APPLE__)))
 
 #define USE_GENERIC_UNWINDER
 
@@ -307,9 +309,26 @@ struct layout
    should to feature a null backchain, AIX might expose a null return
    address instead.  */
 
+/* Then LynxOS-178 features yet another variation, with return_address
+   == &<entrypoint>, with two possible entry points (one for the main
+   process and one for threads). Beware that &bla returns the address
+   of a descriptor when "bla" is a function.  Getting the code address
+   requires an extra dereference.  */
+
+#if defined (__Lynx__)
+extern void __start();  /* process entry point.  */
+extern void __runnit(); /* thread entry point.  */
+#define EXTRA_STOP_CONDITION(CURRENT)                 \
+  ((CURRENT)->return_address == *(void**)&__start     \
+   || (CURRENT)->return_address == *(void**)&__runnit)
+#else
+#define EXTRA_STOP_CONDITION(CURRENT) (0)
+#endif
+
 #define STOP_FRAME(CURRENT, TOP_STACK) \
   (((void *) (CURRENT) < (TOP_STACK)) \
-   || (CURRENT)->return_address == NULL)
+   || (CURRENT)->return_address == NULL \
+   || EXTRA_STOP_CONDITION(CURRENT))
 
 /* The PPC ABI has an interesting specificity: the return address saved by a
    function is located in it's caller's frame, and the save operation only