------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             S E M _ C H 1 2                              --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--          Copyright (C) 1992-2021, Free Software Foundation, Inc.         --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license.          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Inline; use Inline;
with Types;  use Types;

package Sem_Ch12 is
   procedure Analyze_Generic_Package_Declaration        (N : Node_Id);
   procedure Analyze_Generic_Subprogram_Declaration     (N : Node_Id);
   procedure Analyze_Package_Instantiation              (N : Node_Id);
   procedure Analyze_Procedure_Instantiation            (N : Node_Id);
   procedure Analyze_Function_Instantiation             (N : Node_Id);
   procedure Analyze_Formal_Object_Declaration          (N : Node_Id);
   procedure Analyze_Formal_Type_Declaration            (N : Node_Id);
   procedure Analyze_Formal_Subprogram_Declaration      (N : Node_Id);
   procedure Analyze_Formal_Package_Declaration         (N : Node_Id);

   function Build_Function_Wrapper
     (Formal_Subp : Entity_Id;
      Actual_Subp : Entity_Id) return Node_Id;
   --  In GNATprove mode, create a wrapper function for actuals that are
   --  functions with any number of formal parameters, in order to propagate
   --  their contract to the renaming declarations generated for them. This
   --  is called after the renaming declaration created for the formal in the
   --  instance has been analyzed, and the actual is known.

   function Build_Operator_Wrapper
     (Formal_Subp : Entity_Id;
      Actual_Subp : Entity_Id) return Node_Id;
   --  In GNATprove mode, create a wrapper function for actuals that are
   --  operators, in order to propagate their contract to the renaming
   --  declarations generated for them. The types are (the instances of)
   --  the types of the formal subprogram.

   procedure Start_Generic;
   --  Must be invoked before starting to process a generic spec or body

   procedure End_Generic;
   --  Must be invoked just at the end of the end of the processing of a
   --  generic spec or body.

   procedure Check_Generic_Child_Unit
     (Gen_Id           : Node_Id;
      Parent_Installed : in out Boolean);
   --  If the name of the generic unit in an instantiation or a renaming is a
   --  selected component, then the prefix may be an instance and the selector
   --  may designate a child unit. Retrieve the parent generic and search for
   --  the child unit that must be declared within. Similarly, if this is the
   --  name of a generic child unit within an instantiation of its own parent,
   --  retrieve the parent generic. If the parent is installed as a result of
   --  this call, then Parent_Installed is set True, otherwise Parent_Installed
   --  is unchanged by the call.

   function Copy_Generic_Node
     (N             : Node_Id;
      Parent_Id     : Node_Id;
      Instantiating : Boolean) return Node_Id;
   --  Copy the tree for a generic unit or its body. The unit is copied
   --  repeatedly: once to produce a copy on which semantic analysis of
   --  the generic is performed, and once for each instantiation. The tree
   --  being copied is not semantically analyzed, except that references to
   --  global entities are marked on terminal nodes. Note that this function
   --  copies any aspect specifications from the input node N to the returned
   --  node, as well as the setting of the Has_Aspects flag.

   function Get_Instance_Of (A : Entity_Id) return Entity_Id;
   --  Retrieve actual associated with given generic parameter.
   --  If A is uninstantiated or not a generic parameter, return A.

   function Get_Unit_Instantiation_Node (A : Entity_Id) return Node_Id;
   --  Given the entity of a unit that is an instantiation, retrieve the
   --  original instance node. This is used when loading the instantiations
   --  of the ancestors of a child generic that is being instantiated.

   procedure Instantiate_Package_Body
     (Body_Info     : Pending_Body_Info;
      Inlined_Body  : Boolean := False;
      Body_Optional : Boolean := False);
   --  Called after semantic analysis, to complete the instantiation of
   --  package instances. The flag Inlined_Body is set if the body is
   --  being instantiated on the fly for inlining purposes.
   --
   --  The flag Body_Optional indicates that the call is for an instance
   --  that precedes the current instance in the same declarative part.
   --  This call is needed when instantiating a nested generic whose body
   --  is to be found in the body of an instance. Normally we instantiate
   --  package bodies only when they appear in the main unit, or when their
   --  contents are needed for a nested generic G. If unit U contains several
   --  instances I1, I2, etc. and I2 contains a nested generic, then when U
   --  appears in the context of some other unit P that contains an instance
   --  of G, we compile the body of I2, but not that of I1. However, when we
   --  compile U as the main unit, we compile both bodies. This will lead to
   --  link-time errors if the compilation of I1 generates public symbols,
   --  because those in I2 will receive different names in both cases. This
   --  forces us to analyze the body of I1 even when U is not the main unit.
   --  We don't want this additional mechanism to generate an error when the
   --  body of the generic for I1 is not present, and this is the reason for
   --  the presence of the flag Body_Optional, which is exchanged between the
   --  current procedure and Load_Parent_Of_Generic.

   procedure Instantiate_Subprogram_Body
     (Body_Info     : Pending_Body_Info;
      Body_Optional : Boolean := False);
   --  Called after semantic analysis, to complete the instantiation of
   --  function and procedure instances. The flag Body_Optional has the
   --  same purpose as described for Instantiate_Package_Body.

   function Need_Subprogram_Instance_Body
     (N    : Node_Id;
      Subp : Entity_Id) return Boolean;
   --  If a subprogram instance is inlined, indicate that the body of it
   --  must be created, to be used in inlined calls by the back-end. The
   --  subprogram may be inlined because the generic itself carries the
   --  pragma, or because a pragma appears for the instance in the scope.
   --  of the instance.

   procedure Save_Global_References (Templ : Node_Id);
   --  Traverse the original generic unit, and capture all references to
   --  entities that are defined outside of the generic in the analyzed tree
   --  for the template. These references are copied into the original tree,
   --  so that they appear automatically in every instantiation. A critical
   --  invariant in this approach is that if an id in the generic resolves to
   --  a local entity, the corresponding id in the instance will resolve to
   --  the homologous entity in the instance, even though the enclosing context
   --  for resolution is different, as long as the global references have been
   --  captured as described here.

   --  Because instantiations can be nested, the environment of the instance,
   --  involving the actuals and other data-structures, must be saved and
   --  restored in stack-like fashion. Front-end inlining also uses these
   --  structures for the management of private/full views.

   procedure Save_Global_References_In_Aspects (N : Node_Id);
   --  Save all global references found within the expressions of all aspects
   --  that appear on node N.

   procedure Set_Copied_Sloc_For_Inlined_Body (N : Node_Id; E : Entity_Id);
   --  This procedure is used when a subprogram body is inlined. This process
   --  shares the same circuitry as the creation of an instantiated copy of
   --  a generic template. The call to this procedure establishes a new source
   --  file entry representing the inlined body as an instantiation, marked as
   --  an inlined body (so that errout can distinguish cases for generating
   --  error messages, otherwise the treatment is identical). In this call
   --  N is the subprogram body and E is the defining identifier of the
   --  subprogram in question. The resulting Sloc adjustment factor is
   --  saved as part of the internal state of the Sem_Ch12 package for use
   --  in subsequent calls to copy nodes.

   procedure Set_Copied_Sloc_For_Inherited_Pragma
     (N : Node_Id;
      E : Entity_Id);
   --  This procedure is used when a class-wide pre- or postcondition is
   --  inherited. This process shares the same circuitry as the creation of
   --  an instantiated copy of a generic template. The call to this procedure
   --  establishes a new source file entry representing the inherited pragma
   --  as an instantiation, marked as an inherited pragma (so that errout can
   --  distinguish cases for generating error messages, otherwise the treatment
   --  is identical). In this call, N is the subprogram declaration from
   --  which the pragma is inherited and E is the defining identifier of
   --  the overriding subprogram (when the subprogram is redefined) or the
   --  defining identifier of the extension type (when the subprogram is
   --  inherited). The resulting Sloc adjustment factor is saved as part of the
   --  internal state of the Sem_Ch12 package for use in subsequent calls to
   --  copy nodes.

   procedure Adjust_Inherited_Pragma_Sloc (N : Node_Id);
   --  This procedure is used when a class-wide pre- or postcondition
   --  is inherited. It is called on each node of the pragma expression
   --  to adjust its sloc. These call should be preceded by a call to
   --  Set_Copied_Sloc_For_Inherited_Pragma that sets the required sloc
   --  adjustment. This is done directly, instead of using Copy_Generic_Node
   --  to copy nodes and adjust slocs, as Copy_Generic_Node expects a specific
   --  structure to be in place, which is not the case for inherited pragmas.

   procedure Save_Env
     (Gen_Unit : Entity_Id;
      Act_Unit : Entity_Id);
   --  Because instantiations can be nested, the compiler maintains a stack
   --  of environments that holds variables relevant to the current instance:
   --  most importanty Instantiated_Parent, Exchanged_Views, Hidden_Entities,
   --  and others (see full list in Instance_Env).

   procedure Restore_Env;
   --  After processing an instantiation, or aborting one because of semantic
   --  errors, remove the current Instantiation_Env from Instantation_Envs.

   procedure Initialize;
   --  Initializes internal data structures

   procedure Check_Private_View (N : Node_Id);
   --  Check whether the type of a generic entity has a different view between
   --  the point of generic analysis and the point of instantiation. If the
   --  view has changed, then at the point of instantiation we restore the
   --  correct view to perform semantic analysis of the instance, and reset
   --  the current view after instantiation. The processing is driven by the
   --  current private status of the type of the node, and Has_Private_View,
   --  a flag that is set at the point of generic compilation. If view and
   --  flag are inconsistent then the type is updated appropriately.
   --
   --  This subprogram is used in Check_Generic_Actuals and Copy_Generic_Node,
   --  and is exported here for the purpose of front-end inlining (see Exp_Ch6.
   --  Expand_Inlined_Call.Process_Formals).

end Sem_Ch12;