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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                              E X P _ C H 9                               --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2009, 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.      --

--                                                                          --

------------------------------------------------------------------------------

--  Expand routines for chapter 9 constructs

with Types; use Types;

package Exp_Ch9 is

   type Subprogram_Protection_Mode is

     (Dispatching_Mode,

      Protected_Mode,

      Unprotected_Mode);

   --  This type is used to distinguish the different protection modes of a

   --  protected subprogram.

   procedure Build_Activation_Chain_Entity (N : Node_Id);

   --  Given a declaration N of an object that is a task, or contains tasks

   --  (other than allocators to tasks) this routine ensures that an activation

   --  chain has been declared in the appropriate scope, building the required

   --  declaration for the chain variable if not. The name of this variable

   --  is always _Chain and it is accessed by name.

   function Build_Call_With_Task (N : Node_Id; E : Entity_Id) return Node_Id;

   --  N is a node representing the name of a task or an access to a task.

   --  The value returned is a call to the function whose name is the entity

   --  E (typically a runtime routine entity obtained using RTE) with the

   --  Task_Id of the associated task as the parameter. The caller is

   --  responsible for analyzing and resolving the resulting tree.

   function Build_Corresponding_Record

     (N    : Node_Id;

      Ctyp : Node_Id;

      Loc  : Source_Ptr) return Node_Id;

   --  Common to tasks and protected types. Copy discriminant specifications,

   --  build record declaration. N is the type declaration, Ctyp is the

   --  concurrent entity (task type or protected type).

   function Build_Entry_Names (Conc_Typ : Entity_Id) return Node_Id;

   --  Create the statements which populate the entry names array of a task or

   --  protected type. The statements are wrapped inside a block due to a local

   --  declaration.

   procedure Build_Master_Entity (E : Entity_Id);

   --  Given an entity E for the declaration of an object containing tasks

   --  or of a type declaration for an allocator whose designated type is a

   --  task or contains tasks, this routine marks the appropriate enclosing

   --  context as a master, and also declares a variable called _Master in

   --  the current declarative part which captures the value of Current_Master

   --  (if not already built by a prior call). We build this object (instead

   --  of just calling Current_Master) for two reasons. First it is clearly

   --  more efficient to call Current_Master only once for a bunch of tasks

   --  in the same declarative part, and second it makes things easier in

   --  generating the initialization routines, since they can just reference

   --  the object _Master by name, and they will get the proper Current_Master

   --  value at the outer level, and copy in the parameter value for the outer

   --  initialization call if the call is for a nested component). Note that

   --  in the case of nested packages, we only really need to make one such

   --  object at the outer level, but it is much easier to generate one per

   --  declarative part.

   function Build_Private_Protected_Declaration (N : Node_Id) return Entity_Id;

   --  A subprogram body without a previous spec that appears in a protected

   --  body must be expanded separately to create a subprogram declaration

   --  for it, in order to resolve internal calls to it from other protected

   --  operations. It would seem that no locking version of the operation is

   --  needed, but in fact, in Ada 2005 the subprogram may be used in a call-

   --  back, and therefore a protected version of the operation must be

   --  generated as well.

   function Build_Protected_Sub_Specification

     (N        : Node_Id;

      Prot_Typ : Entity_Id;

      Mode     : Subprogram_Protection_Mode) return Node_Id;

   --  Build the specification for protected subprogram. This is called when

   --  expanding a protected type, and also when expanding the declaration for

   --  an Access_To_Protected_Subprogram type. In the latter case, Prot_Typ is

   --  empty, and the first parameter of the signature of the protected op is

   --  of type System.Address.

   procedure Build_Protected_Subprogram_Call

     (N        : Node_Id;

      Name     : Node_Id;

      Rec      : Node_Id;

      External : Boolean := True);

   --  The node N is a subprogram or entry call to a protected subprogram. This

   --  procedure rewrites this call with the appropriate expansion. Name is the

   --  subprogram, and Rec is the record corresponding to the protected object.

   --  External is False if the call is to another protected subprogram within

   --  the same object.

   procedure Build_Task_Activation_Call (N : Node_Id);

   --  This procedure is called for constructs that can be task activators,

   --  i.e. task bodies, subprogram bodies, package bodies and blocks. If the

   --  construct is a task activator (as indicated by the non-empty setting of

   --  Activation_Chain_Entity, either in the construct, or, in the case of a

   --  package body, in its associated package spec), then a call to

   --  Activate_Tasks with this entity as the single parameter is inserted at

   --  the start of the statements of the activator.

   procedure Build_Task_Allocate_Block

     (Actions : List_Id;

      N       : Node_Id;

      Args    : List_Id);

   --  This routine is used in the case of allocators where the designated type

   --  is a task or contains tasks. In this case, the normal initialize call

   --  is replaced by:

   --

   --    blockname : label;

   --    blockname : declare

   --       _Chain  : Activation_Chain;

   --

   --       procedure _Expunge is

   --       begin

   --         Expunge_Unactivated_Tasks (_Chain);

   --       end;

   --

   --    begin

   --       Init (Args);

   --       Activate_Tasks (_Chain);

   --    at end

   --       _Expunge;

   --    end;

   --

   --  to get the task or tasks created and initialized. The expunge call

   --  ensures that any tasks that get created but not activated due to an

   --  exception are properly expunged (it has no effect in the normal case).

   --  The argument N is the allocator, and Args is the list of arguments for

   --  the initialization call, constructed by the caller, which uses the

   --  Master_Id of the access type as the _Master parameter, and _Chain

   --  (defined above) as the _Chain parameter.

   procedure Build_Task_Allocate_Block_With_Init_Stmts

     (Actions    : List_Id;

      N          : Node_Id;

      Init_Stmts : List_Id);

   --  Ada 2005 (AI-287): Similar to previous routine, but used to expand

   --  allocated aggregates with default initialized components. Init_Stmts

   --  contains the list of statements required to initialize the allocated

   --  aggregate. It replaces the call to Init (Args) done by

   --  Build_Task_Allocate_Block.

   function Build_Wrapper_Spec

     (Subp_Id : Entity_Id;

      Obj_Typ : Entity_Id;

      Formals : List_Id) return Node_Id;

   --  Ada 2005 (AI-345): Build the specification of a primitive operation

   --  associated with a protected or task type. This is required to implement

   --  dispatching calls through interfaces. Subp_Id is the primitive to be

   --  wrapped, Obj_Typ is the type of the newly added formal parameter to

   --  handle object notation, Formals are the original entry formals that

   --  will be explicitly replicated.

   function Concurrent_Ref (N : Node_Id) return Node_Id;

   --  Given the name of a concurrent object (task or protected object), or

   --  the name of an access to a concurrent object, this function returns an

   --  expression referencing the associated Task_Id or Protection object,

   --  respectively. Note that a special case is when the name is a reference

   --  to a task type name. This can only happen within a task body, and the

   --  meaning is to get the Task_Id for the currently executing task.

   function Convert_Concurrent

     (N   : Node_Id;

      Typ : Entity_Id) return Node_Id;

   --  N is an expression of type Typ. If the type is not a concurrent type

   --  then it is returned unchanged. If it is a task or protected reference,

   --  Convert_Concurrent creates an unchecked conversion node from this

   --  expression to the corresponding concurrent record type value. We need

   --  this in any situation where the concurrent type is used, because the

   --  actual concurrent object is an object of the corresponding concurrent

   --  type, and manipulations on the concurrent object actually manipulate the

   --  corresponding object of the record type.

   function Entry_Index_Expression

     (Sloc  : Source_Ptr;

      Ent   : Entity_Id;

      Index : Node_Id;

      Ttyp  : Entity_Id)

      return  Node_Id;

   --  Returns an expression to compute a task entry index given the name of

   --  the entry or entry family. For the case of a task entry family, the

   --  Index parameter contains the expression for the subscript. Ttyp is the

   --  task type.

   procedure Establish_Task_Master (N : Node_Id);

   --  Given a subprogram body, or a block statement, or a task body, this

   --  procedure makes the necessary transformations required of a task master

   --  (add Enter_Master call at start, and establish a cleanup routine to make

   --  sure Complete_Master is called on exit).

   procedure Expand_Access_Protected_Subprogram_Type (N : Node_Id);

   --  Build Equivalent_Type for an Access_To_Protected_Subprogram.

   --  Equivalent_Type is a record type with two components: a pointer to the

   --  protected object, and a pointer to the operation itself.

   procedure Expand_Accept_Declarations (N : Node_Id; Ent : Entity_Id);

   --  Expand declarations required for accept statement. See bodies of both

   --  Expand_Accept_Declarations and Expand_N_Accept_Statement for full

   --  details of the nature and use of these declarations, which are inserted

   --  immediately before the accept node N. The second argument is the entity

   --  for the corresponding entry.

   procedure Expand_Entry_Barrier (N : Node_Id; Ent : Entity_Id);

   --  Expand the entry barrier into a function. This is called directly

   --  from Analyze_Entry_Body so that the discriminals and privals of the

   --  barrier can be attached to the function declaration list, and a new

   --  set prepared for the entry body procedure, before the entry body

   --  statement sequence can be expanded. The resulting function is analyzed

   --  now, within the context of the protected object, to resolve calls to

   --  other protected functions.

   procedure Expand_N_Abort_Statement            (N : Node_Id);

   procedure Expand_N_Accept_Statement           (N : Node_Id);

   procedure Expand_N_Asynchronous_Select        (N : Node_Id);

   procedure Expand_N_Conditional_Entry_Call     (N : Node_Id);

   procedure Expand_N_Delay_Relative_Statement   (N : Node_Id);

   procedure Expand_N_Delay_Until_Statement      (N : Node_Id);

   procedure Expand_N_Entry_Body                 (N : Node_Id);

   procedure Expand_N_Entry_Call_Statement       (N : Node_Id);

   procedure Expand_N_Entry_Declaration          (N : Node_Id);

   procedure Expand_N_Protected_Body             (N : Node_Id);

   procedure Expand_N_Protected_Type_Declaration (N : Node_Id);

   --  Expands protected type declarations. This results, among other things,

   --  in the declaration of a record type for the representation of protected

   --  objects and (if there are entries) in an entry service procedure. The

   --  Protection value used by the GNARL to control the object will always be

   --  the first field of the record, and the entry service procedure spec (if

   --  it exists) will always immediately follow the record declaration. This

   --  allows these two nodes to be found from the type, without benefit of

   --  further attributes, using Corresponding_Record.

   procedure Expand_N_Requeue_Statement          (N : Node_Id);

   procedure Expand_N_Selective_Accept           (N : Node_Id);

   procedure Expand_N_Single_Task_Declaration    (N : Node_Id);

   procedure Expand_N_Task_Body                  (N : Node_Id);

   procedure Expand_N_Task_Type_Declaration      (N : Node_Id);

   procedure Expand_N_Timed_Entry_Call           (N : Node_Id);

   procedure Expand_Protected_Body_Declarations

     (N       : Node_Id;

      Spec_Id : Entity_Id);

   --  Expand declarations required for a protected body. See bodies of both

   --  Expand_Protected_Body_Declarations and Expand_N_Protected_Body for full

   --  details of the nature and use of these declarations. The second argument

   --  is the entity for the corresponding protected type declaration.

   function External_Subprogram (E : Entity_Id) return Entity_Id;

   --  return the external version of a protected operation, which locks

   --  the object before invoking the internal protected subprogram body.

   function First_Protected_Operation (D : List_Id) return Node_Id;

   --  Given the declarations list for a protected body, find the

   --  first protected operation body.

   procedure Install_Private_Data_Declarations

     (Loc      : Source_Ptr;

      Spec_Id  : Entity_Id;

      Conc_Typ : Entity_Id;

      Body_Nod : Node_Id;

      Decls    : List_Id;

      Barrier  : Boolean := False;

      Family   : Boolean := False);

   --  This routines generates several types, objects and object renamings used

   --  in the handling of discriminants and private components of protected and

   --  task types. It also generates the entry index for entry families. Formal

   --  Spec_Id denotes an entry, entry family or a subprogram, Conc_Typ is the

   --  concurrent type where Spec_Id resides, Body_Nod is the corresponding

   --  body of Spec_Id, Decls are the declarations of the subprogram or entry.

   --  Flag Barrier denotes whether the context is an entry barrier function.

   --  Flag Family is used in conjunction with Barrier to denote a barrier for

   --  an entry family.

   --

   --  The generated types, entities and renamings are:

   --

   --  * If flag Barrier is set or Spec_Id denotes a protected entry or an

   --    entry family, generate:

   --

   --      type prot_typVP is access prot_typV;

   --      _object : prot_typVP := prot_typV (_O);

   --

   --    where prot_typV is the corresponding record of a protected type and

   --    _O is a formal parameter representing the concurrent object of either

   --    the barrier function or the entry (family).

   --

   --  * If Conc_Typ is a protected type, create a renaming for the Protection

   --    field _object:

   --

   --      conc_typR : protection_typ renames _object._object;

   --

   --  * If Conc_Typ has discriminants, create renamings of the form:

   --

   --      discr_nameD : discr_typ renames _object.discr_name;

   --        or

   --      discr_nameD : discr_typ renames _task.discr_name;

   --

   --  * If Conc_Typ denotes a protected type and has private components,

   --    generate renamings of the form:

   --

   --      comp_name : comp_typ renames _object.comp_name;

   --

   --  * Finally, is flag Barrier and Family are set or Spec_Id denotes an

   --    entry family, generate the entry index constant:

   --

   --      subtype Jnn is <Type of Index> range Low .. High;

   --      J : constant Jnn :=

   --            Jnn'Val (_E - <Index expression> + Jnn'Pos (Jnn'First));

   --

   --  All the above declarations are inserted in the order shown to the front

   --  of Decls.

   function Make_Task_Create_Call (Task_Rec : Entity_Id) return Node_Id;

   --  Given the entity of the record type created for a task type, build

   --  the call to Create_Task

   function Make_Initialize_Protection

     (Protect_Rec : Entity_Id) return List_Id;

   --  Given the entity of the record type created for a protected type, build

   --  a list of statements needed for proper initialization of the object.

   function Next_Protected_Operation (N : Node_Id) return Node_Id;

   --  Given a protected operation node (a subprogram or entry body), find the

   --  following node in the declarations list.

   procedure Set_Discriminals (Dec : Node_Id);

   --  Replace discriminals in a protected type for use by the next protected

   --  operation on the type. Each operation needs a new set of discriminals,

   --  since it needs a unique renaming of the discriminant fields in the

   --  record used to implement the protected type.

end Exp_Ch9;