gcc/ada/exp_ch9.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              E X P _ C H 9                               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- GNAT was originally developed  by the GNAT team at  New York University. --
  24 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  25 --                                                                          --
  26 ------------------------------------------------------------------------------
  27
  28 --  Expand routines for chapter 9 constructs
  29
  30 with Types; use Types;
  31
  32 package Exp_Ch9 is
  33
  34    procedure Add_Discriminal_Declarations
  35      (Decls : List_Id;
  36       Typ   : Entity_Id;
  37       Name  : Name_Id;
  38       Loc   : Source_Ptr);
  39    --  This routine is used to add discriminal declarations to task and
  40    --  protected operation bodies. The discriminants are available by normal
  41    --  selection from the concurrent object (whose name is passed as the third
  42    --  parameter). Discriminant references inside the body have already
  43    --  been replaced by references to the corresponding discriminals. The
  44    --  declarations constructed by this procedure hook the references up with
  45    --  the objects:
  46    --
  47    --    discriminal_name : discr_type renames name.discriminant_name;
  48    --
  49    --  Obviously we could have expanded the discriminant references in the
  50    --  first place to be the appropriate selection, but this turns out to
  51    --  be hard to do because it would introduce difference in handling of
  52    --  discriminant references depending on their location.
  53
  54    procedure Add_Private_Declarations
  55      (Decls : List_Id;
  56       Typ   : Entity_Id;
  57       Name  : Name_Id;
  58       Loc : Source_Ptr);
  59    --  This routine is used to add private declarations to protected bodies.
  60    --  These are analogous to the discriminal declarations added to tasks
  61    --  and protected operations, and consist of a renaming of each private
  62    --  object to a selection from the concurrent object passed as an extra
  63    --  parameter to each such operation:
  64    --    private_name : private_type renames name.private_name;
  65    --  As with discriminals, private references inside the protected
  66    --  subprogram bodies have already been replaced by references to the
  67    --  corresponding privals.
  68
  69    procedure Build_Activation_Chain_Entity (N : Node_Id);
  70    --  Given a declaration N of an object that is a task, or contains tasks
  71    --  (other than allocators to tasks) this routine ensures that an activation
  72    --  chain has been declared in the appropriate scope, building the required
  73    --  declaration for the chain variable if not. The name of this variable
  74    --  is always _Chain and it is accessed by name. This procedure also adds
  75    --  an appropriate call to Activate_Tasks to activate the tasks for this
  76    --  activation chain. It does not however deal with the call needed in the
  77    --  case of allocators to Expunge_Unactivated_Tasks, this is separately
  78    --  handled in the Expand_Task_Allocator routine.
  79
  80    function Build_Call_With_Task (N : Node_Id; E : Entity_Id) return Node_Id;
  81    --  N is a node representing the name of a task or an access to a task.
  82    --  The value returned is a call to the function whose name is the entity
  83    --  E (typically a runtime routine entity obtained using RTE) with the
  84    --  Task_Id of the associated task as the parameter. The caller is
  85    --  responsible for analyzing and resolving the resulting tree.
  86
  87    procedure Build_Master_Entity (E : Entity_Id);
  88    --  Given an entity E for the declaration of an object containing tasks
  89    --  or of a type declaration for an allocator whose designated type is a
  90    --  task or contains tasks, this routine marks the appropriate enclosing
  91    --  context as a master, and also declares a variable called _Master in
  92    --  the current declarative part which captures the value of Current_Master
  93    --  (if not already built by a prior call). We build this object (instead
  94    --  of just calling Current_Master) for two reasons. First it is clearly
  95    --  more efficient to call Current_Master only once for a bunch of tasks
  96    --  in the same declarative part, and second it makes things easier in
  97    --  generating the initialization routines, since they can just reference
  98    --  the object _Master by name, and they will get the proper Current_Master
  99    --  value at the outer level, and copy in the parameter value for the outer
 100    --  initialization call if the call is for a nested component). Note that
 101    --  in the case of nested packages, we only really need to make one such
 102    --  object at the outer level, but it is much easier to generate one per
 103    --  declarative part.
 104
 105    function Build_Protected_Sub_Specification
 106      (N           : Node_Id;
 107       Prottyp     : Entity_Id;
 108       Unprotected : Boolean := False)
 109       return        Node_Id;
 110    --  Build specification for protected subprogram. This is called when
 111    --  expanding a protected type, and also when expanding the declaration for
 112    --  an Access_To_Protected_Subprogram type. In the latter case, Prottyp is
 113    --  empty, and the first parameter of the signature of the protected op is
 114    --  of type System.Address.
 115
 116    procedure Build_Protected_Subprogram_Call
 117      (N        : Node_Id;
 118       Name     : Node_Id;
 119       Rec      : Node_Id;
 120       External : Boolean := True);
 121    --  The node N is a subprogram or entry call to a protected subprogram.
 122    --  This procedure rewrites this call with the appropriate expansion.
 123    --  Name is the subprogram, and Rec is the record corresponding to the
 124    --  protected object. External is False if the call is to another
 125    --  protected subprogram within the same object.
 126
 127    procedure Build_Task_Activation_Call (N : Node_Id);
 128    --  This procedure is called for constructs that can be task activators
 129    --  i.e. task bodies, subprogram bodies, package bodies and blocks. If
 130    --  the construct is a task activator (as indicated by the non-empty
 131    --  setting of Activation_Chain_Entity, either in the construct, or, in
 132    --  the case of a package body, in its associated package spec), then
 133    --  a call to Activate_Tasks with this entity as the single parameter
 134    --  is inserted at the start of the statements of the activator.
 135
 136    procedure Build_Task_Allocate_Block
 137      (Actions : List_Id;
 138       N       : Node_Id;
 139       Args    : List_Id);
 140    --  This routine is used in the case of allocators where the designated
 141    --  type is a task or contains tasks. In this case, the normal initialize
 142    --  call is replaced by:
 143    --
 144    --    blockname : label;
 145    --    blockname : declare
 146    --       _Chain  : Activation_Chain;
 147    --
 148    --       procedure _Expunge is
 149    --       begin
 150    --         Expunge_Unactivated_Tasks (_Chain);
 151    --       end;
 152    --
 153    --    begin
 154    --       Init (Args);
 155    --       Activate_Tasks (_Chain);
 156    --    at end
 157    --       _Expunge;
 158    --    end;
 159    --
 160    --  to get the task or tasks created and initialized. The expunge call
 161    --  ensures that any tasks that get created but not activated due to an
 162    --  exception are properly expunged (it has no effect in the normal case)
 163    --  The argument N is the allocator, and Args is the list of arguments
 164    --  for the initialization call, constructed by the caller, which uses
 165    --  the Master_Id of the access type as the _Master parameter, and _Chain
 166    --  (defined above) as the _Chain parameter.
 167
 168    function Concurrent_Ref (N : Node_Id) return Node_Id;
 169    --  Given the name of a concurrent object (task or protected object), or
 170    --  the name of an access to a concurrent object, this function returns an
 171    --  expression referencing the associated Task_Id or Protection object,
 172    --  respectively. Note that a special case is when the name is a reference
 173    --  to a task type name. This can only happen within a task body, and the
 174    --  meaning is to get the Task_Id for the currently executing task.
 175
 176    function Convert_Concurrent
 177      (N    : Node_Id;
 178       Typ  : Entity_Id)
 179       return Node_Id;
 180    --  N is an expression of type Typ. If the type is not a concurrent
 181    --  type then it is returned unchanged. If it is a task or protected
 182    --  reference, Convert_Concurrent creates an unchecked conversion node
 183    --  from this expression to the corresponding concurrent record type
 184    --  value. We need this in any situation where the concurrent type is
 185    --  used, because the actual concurrent object is an object of the
 186    --  corresponding concurrent type, and manipulations on the concurrent
 187    --  object actually manipulate the corresponding object of the record
 188    --  type.
 189
 190    function Entry_Index_Expression
 191      (Sloc  : Source_Ptr;
 192       Ent   : Entity_Id;
 193       Index : Node_Id;
 194       Ttyp  : Entity_Id)
 195       return  Node_Id;
 196    --  Returns an expression to compute a task entry index given the name
 197    --  of the entry or entry family. For the case of a task entry family,
 198    --  the Index parameter contains the expression for the subscript.
 199    --  Ttyp is the task type.
 200
 201    procedure Establish_Task_Master (N : Node_Id);
 202    --  Given a subprogram body, or a block statement, or a task body, this
 203    --  proccedure makes the necessary transformations required of a task
 204    --  master (add Enter_Master call at start, and establish a cleanup
 205    --  routine to make sure Complete_Master is called on exit).
 206
 207    procedure Expand_Access_Protected_Subprogram_Type (N : Node_Id);
 208    --  Build Equivalent_Type for an Access_to_protected_Subprogram.
 209
 210    procedure Expand_Accept_Declarations (N : Node_Id; Ent : Entity_Id);
 211    --  Expand declarations required for accept statement. See bodies of
 212    --  both Expand_Accept_Declarations and Expand_N_Accept_Statement for
 213    --  full details of the nature and use of these declarations, which
 214    --  are inserted immediately before the accept node N. The second
 215    --  argument is the entity for the corresponding entry.
 216
 217    procedure Expand_Entry_Barrier (N : Node_Id; Ent : Entity_Id);
 218    --  Expand the entry barrier into a function. This is called directly
 219    --  from Analyze_Entry_Body so that the discriminals and privals of the
 220    --  barrier can be attached to the function declaration list, and a new
 221    --  set prepared for the entry body procedure, bedore the entry body
 222    --  statement sequence can be expanded. The resulting function is analyzed
 223    --  now, within the context of the protected object, to resolve calls to
 224    --  other protected functions.
 225
 226    procedure Expand_Entry_Body_Declarations (N : Node_Id);
 227    --  Expand declarations required for the expansion of the
 228    --  statements of the body.
 229
 230    procedure Expand_N_Abort_Statement            (N : Node_Id);
 231    procedure Expand_N_Accept_Statement           (N : Node_Id);
 232    procedure Expand_N_Asynchronous_Select        (N : Node_Id);
 233    procedure Expand_N_Conditional_Entry_Call     (N : Node_Id);
 234    procedure Expand_N_Delay_Relative_Statement   (N : Node_Id);
 235    procedure Expand_N_Delay_Until_Statement      (N : Node_Id);
 236    procedure Expand_N_Entry_Body                 (N : Node_Id);
 237    procedure Expand_N_Entry_Call_Statement       (N : Node_Id);
 238    procedure Expand_N_Entry_Declaration          (N : Node_Id);
 239    procedure Expand_N_Protected_Body             (N : Node_Id);
 240
 241    procedure Expand_N_Protected_Type_Declaration (N : Node_Id);
 242    --  Expands protected type declarations. This results, among
 243    --  other things, in the declaration of a record type for the
 244    --  representation of protected objects and (if there are entries)
 245    --  in an entry service procedure. The Protection value used by
 246    --  the GNARL to control the object will always be the first
 247    --  field of the record, and the entry service procedure spec
 248    --  (if it exists) will always immediately follow the record
 249    --  declaration. This allows these two nodes to be found from
 250    --  the type using Corresponding_Record, without benefit of
 251    --  of further attributes.
 252
 253    procedure Expand_N_Requeue_Statement          (N : Node_Id);
 254    procedure Expand_N_Selective_Accept           (N : Node_Id);
 255    procedure Expand_N_Single_Task_Declaration    (N : Node_Id);
 256    procedure Expand_N_Task_Body                  (N : Node_Id);
 257    procedure Expand_N_Task_Type_Declaration      (N : Node_Id);
 258    procedure Expand_N_Timed_Entry_Call           (N : Node_Id);
 259
 260    procedure Expand_Protected_Body_Declarations
 261      (N       : Node_Id;
 262       Spec_Id : Entity_Id);
 263    --  Expand declarations required for a protected body. See bodies of
 264    --  both Expand_Protected_Body_Declarations and Expand_N_Protected_Body
 265    --  for full details of the nature and use of these declarations.
 266    --  The second argument is the entity for the corresponding
 267    --  protected type declaration.
 268
 269    function External_Subprogram (E : Entity_Id) return Entity_Id;
 270    --  return the external version of a protected operation, which locks
 271    --  the object before invoking the internal protected subprogram body.
 272
 273    function First_Protected_Operation (D : List_Id) return Node_Id;
 274    --  Given the declarations list for a protected body, find the
 275    --  first protected operation body.
 276
 277    function Make_Task_Create_Call (Task_Rec : Entity_Id) return Node_Id;
 278    --  Given the entity of the record type created for a task type, build
 279    --  the call to Create_Task
 280
 281    function Make_Initialize_Protection
 282      (Protect_Rec : Entity_Id)
 283       return        List_Id;
 284    --  Given the entity of the record type created for a protected type, build
 285    --  a list of statements needed for proper initialization of the object.
 286
 287    function Next_Protected_Operation (N : Node_Id) return Node_Id;
 288    --  Given a protected operation node (a subprogram or entry body),
 289    --  find the following node in the declarations list.
 290
 291    procedure Set_Discriminals (Dec : Node_Id);
 292    --  Replace discriminals in a protected type for use by the
 293    --  next protected operation on the type. Each operation needs a
 294    --  new set of discirminals, since it needs a unique renaming of
 295    --  the discriminant fields in the record used to implement the
 296    --  protected type.
 297
 298    procedure Set_Privals
 299       (Dec : Node_Id;
 300        Op  : Node_Id;
 301        Loc : Source_Ptr);
 302    --  Associates a new set of privals (placeholders for later access to
 303    --  private components of protected objects) with the private object
 304    --  declarations of a protected object. These will be used to expand
 305    --  the references to private objects in the next protected
 306    --  subprogram or entry body to be expanded.
 307
 308 end Exp_Ch9;