[Ada] Unnesting: fix handling of up level refs for entries

2018-09-26  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* exp_unst.adb: Fix handling of up level references for entries.

From-SVN: r264603

gcc/ada/ChangeLog

 2018-09-26  Ed Schonberg  <schonberg@adacore.com>
 
+	* exp_unst.adb: Fix handling of up level references for entries.
+
+2018-09-26  Ed Schonberg  <schonberg@adacore.com>
+
 	* contracts.adb (Expand_Subprogram_Contract,
 	Process_Preconditions_For): Apply Freeze_Expr_Types to the
 	expression for a precondition of an expression function that is

gcc/ada/exp_unst.adb

@@ -260,8 +260,8 @@ package body Exp_Unst is
          E := Ultimate_Alias (E);
 
          --  The body of a protected operation has a different name and
-         --  has been scanned at this point, and thus has an entry in the
-         --  subprogram table.
+         --  has been scanned at this point, and thus has an entry in
+         --  the subprogram table.
 
          if E = Sub and then Convention (E) = Convention_Protected then
             E := Protected_Body_Subprogram (E);
@@ -535,6 +535,29 @@ package body Exp_Unst is
                         end loop;
                      end;
 
+                     --  The type of the prefix may be have an uplevel
+                     --  reference if this needs bounds.
+
+                     if Nkind (N) = N_Attribute_Reference then
+                        declare
+                           Attr : constant Attribute_Id :=
+                             Get_Attribute_Id (Attribute_Name (N));
+                        begin
+                           if (Attr = Attribute_First
+                                 or else Attr = Attribute_Last
+                                 or else Attr = Attribute_Length)
+                             and then Is_Constrained (Etype (Prefix (N)))
+                           then
+                              declare
+                                 DT : Boolean := False;
+                              begin
+                                 Check_Static_Type
+                                   (Etype (Prefix (N)), Empty, DT);
+                              end;
+                           end if;
+                        end;
+                     end if;
+
                   --  Binary operator cases. These can apply to arrays for
                   --  which we may need bounds.
 
@@ -699,6 +722,9 @@ package body Exp_Unst is
                  and then Corresponding_Procedure (Callee) = Caller
                then
                   return;
+
+               elsif Ekind_In (Callee, E_Entry, E_Entry_Family) then
+                  return;
                end if;
 
                --  We have a new uplevel referenced entity
@@ -748,6 +774,22 @@ package body Exp_Unst is
                    ARECnU        => Empty));
 
                Set_Subps_Index (E, UI_From_Int (Subps.Last));
+
+               --  If we marked this reachable because it's in a synchronized
+               --  unit, we have to mark all enclosing subprograms as reachable
+               --  as well.
+
+               if In_Synchronized_Unit (E) then
+                  declare
+                     S : Entity_Id := E;
+
+                  begin
+                     for J in reverse 1 .. L  - 1 loop
+                        S := Enclosing_Subprogram (S);
+                        Subps.Table (Subp_Index (S)).Reachable := True;
+                     end loop;
+                  end;
+               end if;
             end Register_Subprogram;
 
          --  Start of processing for Visit_Node
@@ -1109,12 +1151,24 @@ package body Exp_Unst is
                   end if;
 
                --  Pragmas and component declarations can be ignored
+               --  Quantified expressions are expanded into explicit loops
+               --  and the original epression must be ignored.
 
                when N_Component_Declaration
                   | N_Pragma
+                  | N_Quantified_Expression
                =>
                   return Skip;
 
+               --  We want to skip the function spec for a generic function
+               --  to avoid looking at any generic types that might be in
+               --  its formals.
+
+               when N_Function_Specification =>
+                  if Is_Generic_Subprogram  (Unique_Defining_Entity (N)) then
+                     return Skip;
+                  end if;
+
                --  Otherwise record an uplevel reference in a local identifier
 
                when others =>
@@ -1965,13 +2019,26 @@ package body Exp_Unst is
                                  --  If we have a loop parameter, we have
                                  --  to insert before the first statement
                                  --  of the loop. Ins points to the
-                                 --  N_Loop_Parameter_Specification.
-
-                                 if Ekind (Ent) = E_Loop_Parameter then
-                                    Ins :=
-                                      First
-                                        (Statements (Parent (Parent (Ins))));
-                                    Insert_Before (Ins, Asn);
+                                 --  N_Loop_Parameter_Specification or to
+                                 --  an N_Iterator_Specification.
+
+                                 if Nkind_In (Ins, N_Iterator_Specification,
+                                              N_Loop_Parameter_Specification)
+                                 then
+                                    --  Quantified expression are rewrittne
+                                    --  as loops during expansion.
+
+                                    if Nkind (Parent (Ins)) =
+                                      N_Quantified_Expression
+                                    then
+                                       null;
+
+                                    else
+                                       Ins :=
+                                         First
+                                         (Statements (Parent (Parent (Ins))));
+                                       Insert_Before (Ins, Asn);
+                                    end if;
 
                                  else
                                     Insert_After (Ins, Asn);
@@ -2369,6 +2436,13 @@ package body Exp_Unst is
 
          elsif Nkind (N) in N_Body_Stub then
             Do_Search (Library_Unit (N));
+
+         --  Skip generic packages
+
+         elsif Nkind (N) = N_Package_Body
+           and then Ekind (Corresponding_Spec (N)) = E_Generic_Package
+         then
+            return Skip;
          end if;
 
          return OK;