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 --          Copyright (C) 1992-2008, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  Expand routines for chapter 9 constructs
  27
  28 with Types; use Types;
  29
  30 package Exp_Ch9 is
  31
  32    type Subprogram_Protection_Mode is
  33      (Dispatching_Mode,
  34       Protected_Mode,
  35       Unprotected_Mode);
  36    --  This type is used to distinguish the different protection modes of a
  37    --  protected subprogram.
  38
  39    procedure Build_Activation_Chain_Entity (N : Node_Id);
  40    --  Given a declaration N of an object that is a task, or contains tasks
  41    --  (other than allocators to tasks) this routine ensures that an activation
  42    --  chain has been declared in the appropriate scope, building the required
  43    --  declaration for the chain variable if not. The name of this variable
  44    --  is always _Chain and it is accessed by name.
  45
  46    function Build_Call_With_Task (N : Node_Id; E : Entity_Id) return Node_Id;
  47    --  N is a node representing the name of a task or an access to a task.
  48    --  The value returned is a call to the function whose name is the entity
  49    --  E (typically a runtime routine entity obtained using RTE) with the
  50    --  Task_Id of the associated task as the parameter. The caller is
  51    --  responsible for analyzing and resolving the resulting tree.
  52
  53    function Build_Corresponding_Record
  54      (N    : Node_Id;
  55       Ctyp : Node_Id;
  56       Loc  : Source_Ptr) return Node_Id;
  57    --  Common to tasks and protected types. Copy discriminant specifications,
  58    --  build record declaration. N is the type declaration, Ctyp is the
  59    --  concurrent entity (task type or protected type).
  60
  61    function Build_Entry_Names (Conc_Typ : Entity_Id) return Node_Id;
  62    --  Create the statements which populate the entry names array of a task or
  63    --  protected type. The statements are wrapped inside a block due to a local
  64    --  declaration.
  65
  66    procedure Build_Master_Entity (E : Entity_Id);
  67    --  Given an entity E for the declaration of an object containing tasks
  68    --  or of a type declaration for an allocator whose designated type is a
  69    --  task or contains tasks, this routine marks the appropriate enclosing
  70    --  context as a master, and also declares a variable called _Master in
  71    --  the current declarative part which captures the value of Current_Master
  72    --  (if not already built by a prior call). We build this object (instead
  73    --  of just calling Current_Master) for two reasons. First it is clearly
  74    --  more efficient to call Current_Master only once for a bunch of tasks
  75    --  in the same declarative part, and second it makes things easier in
  76    --  generating the initialization routines, since they can just reference
  77    --  the object _Master by name, and they will get the proper Current_Master
  78    --  value at the outer level, and copy in the parameter value for the outer
  79    --  initialization call if the call is for a nested component). Note that
  80    --  in the case of nested packages, we only really need to make one such
  81    --  object at the outer level, but it is much easier to generate one per
  82    --  declarative part.
  83
  84    function Build_Protected_Sub_Specification
  85      (N        : Node_Id;
  86       Prot_Typ : Entity_Id;
  87       Mode     : Subprogram_Protection_Mode) return Node_Id;
  88    --  Build the specification for protected subprogram. This is called when
  89    --  expanding a protected type, and also when expanding the declaration for
  90    --  an Access_To_Protected_Subprogram type. In the latter case, Prot_Typ is
  91    --  empty, and the first parameter of the signature of the protected op is
  92    --  of type System.Address.
  93
  94    procedure Build_Protected_Subprogram_Call
  95      (N        : Node_Id;
  96       Name     : Node_Id;
  97       Rec      : Node_Id;
  98       External : Boolean := True);
  99    --  The node N is a subprogram or entry call to a protected subprogram.
 100    --  This procedure rewrites this call with the appropriate expansion.
 101    --  Name is the subprogram, and Rec is the record corresponding to the
 102    --  protected object. External is False if the call is to another
 103    --  protected subprogram within the same object.
 104
 105    procedure Build_Task_Activation_Call (N : Node_Id);
 106    --  This procedure is called for constructs that can be task activators
 107    --  i.e. task bodies, subprogram bodies, package bodies and blocks. If
 108    --  the construct is a task activator (as indicated by the non-empty
 109    --  setting of Activation_Chain_Entity, either in the construct, or, in
 110    --  the case of a package body, in its associated package spec), then
 111    --  a call to Activate_Tasks with this entity as the single parameter
 112    --  is inserted at the start of the statements of the activator.
 113
 114    procedure Build_Task_Allocate_Block
 115      (Actions : List_Id;
 116       N       : Node_Id;
 117       Args    : List_Id);
 118    --  This routine is used in the case of allocators where the designated
 119    --  type is a task or contains tasks. In this case, the normal initialize
 120    --  call is replaced by:
 121    --
 122    --    blockname : label;
 123    --    blockname : declare
 124    --       _Chain  : Activation_Chain;
 125    --
 126    --       procedure _Expunge is
 127    --       begin
 128    --         Expunge_Unactivated_Tasks (_Chain);
 129    --       end;
 130    --
 131    --    begin
 132    --       Init (Args);
 133    --       Activate_Tasks (_Chain);
 134    --    at end
 135    --       _Expunge;
 136    --    end;
 137    --
 138    --  to get the task or tasks created and initialized. The expunge call
 139    --  ensures that any tasks that get created but not activated due to an
 140    --  exception are properly expunged (it has no effect in the normal case)
 141    --  The argument N is the allocator, and Args is the list of arguments
 142    --  for the initialization call, constructed by the caller, which uses
 143    --  the Master_Id of the access type as the _Master parameter, and _Chain
 144    --  (defined above) as the _Chain parameter.
 145
 146    procedure Build_Task_Allocate_Block_With_Init_Stmts
 147      (Actions    : List_Id;
 148       N          : Node_Id;
 149       Init_Stmts : List_Id);
 150    --  Ada 2005 (AI-287): Similar to previous routine, but used to expand
 151    --  allocated aggregates with default initialized components. Init_Stmts
 152    --  contains the list of statements required to initialize the allocated
 153    --  aggregate. It replaces the call to Init (Args) done by
 154    --  Build_Task_Allocate_Block.
 155
 156    function Concurrent_Ref (N : Node_Id) return Node_Id;
 157    --  Given the name of a concurrent object (task or protected object), or
 158    --  the name of an access to a concurrent object, this function returns an
 159    --  expression referencing the associated Task_Id or Protection object,
 160    --  respectively. Note that a special case is when the name is a reference
 161    --  to a task type name. This can only happen within a task body, and the
 162    --  meaning is to get the Task_Id for the currently executing task.
 163
 164    function Convert_Concurrent
 165      (N    : Node_Id;
 166       Typ  : Entity_Id) return Node_Id;
 167    --  N is an expression of type Typ. If the type is not a concurrent type
 168    --  then it is returned unchanged. If it is a task or protected reference,
 169    --  Convert_Concurrent creates an unchecked conversion node from this
 170    --  expression to the corresponding concurrent record type value. We need
 171    --  this in any situation where the concurrent type is used, because the
 172    --  actual concurrent object is an object of the corresponding concurrent
 173    --  type, and manipulations on the concurrent object actually manipulate the
 174    --  corresponding object of the record type.
 175
 176    function Entry_Index_Expression
 177      (Sloc  : Source_Ptr;
 178       Ent   : Entity_Id;
 179       Index : Node_Id;
 180       Ttyp  : Entity_Id)
 181       return  Node_Id;
 182    --  Returns an expression to compute a task entry index given the name
 183    --  of the entry or entry family. For the case of a task entry family,
 184    --  the Index parameter contains the expression for the subscript.
 185    --  Ttyp is the task type.
 186
 187    procedure Establish_Task_Master (N : Node_Id);
 188    --  Given a subprogram body, or a block statement, or a task body, this
 189    --  procedure makes the necessary transformations required of a task
 190    --  master (add Enter_Master call at start, and establish a cleanup
 191    --  routine to make sure Complete_Master is called on exit).
 192
 193    procedure Expand_Access_Protected_Subprogram_Type (N : Node_Id);
 194    --  Build Equivalent_Type for an Access_to_protected_Subprogram
 195
 196    procedure Expand_Accept_Declarations (N : Node_Id; Ent : Entity_Id);
 197    --  Expand declarations required for accept statement. See bodies of
 198    --  both Expand_Accept_Declarations and Expand_N_Accept_Statement for
 199    --  full details of the nature and use of these declarations, which
 200    --  are inserted immediately before the accept node N. The second
 201    --  argument is the entity for the corresponding entry.
 202
 203    procedure Expand_Entry_Barrier (N : Node_Id; Ent : Entity_Id);
 204    --  Expand the entry barrier into a function. This is called directly
 205    --  from Analyze_Entry_Body so that the discriminals and privals of the
 206    --  barrier can be attached to the function declaration list, and a new
 207    --  set prepared for the entry body procedure, before the entry body
 208    --  statement sequence can be expanded. The resulting function is analyzed
 209    --  now, within the context of the protected object, to resolve calls to
 210    --  other protected functions.
 211
 212    procedure Expand_N_Abort_Statement            (N : Node_Id);
 213    procedure Expand_N_Accept_Statement           (N : Node_Id);
 214    procedure Expand_N_Asynchronous_Select        (N : Node_Id);
 215    procedure Expand_N_Conditional_Entry_Call     (N : Node_Id);
 216    procedure Expand_N_Delay_Relative_Statement   (N : Node_Id);
 217    procedure Expand_N_Delay_Until_Statement      (N : Node_Id);
 218    procedure Expand_N_Entry_Body                 (N : Node_Id);
 219    procedure Expand_N_Entry_Call_Statement       (N : Node_Id);
 220    procedure Expand_N_Entry_Declaration          (N : Node_Id);
 221    procedure Expand_N_Protected_Body             (N : Node_Id);
 222
 223    procedure Expand_N_Protected_Type_Declaration (N : Node_Id);
 224    --  Expands protected type declarations. This results, among other things,
 225    --  in the declaration of a record type for the representation of protected
 226    --  objects and (if there are entries) in an entry service procedure. The
 227    --  Protection value used by the GNARL to control the object will always be
 228    --  the first field of the record, and the entry service procedure spec (if
 229    --  it exists) will always immediately follow the record declaration. This
 230    --  allows these two nodes to be found from the type, without benefit of
 231    --  further attributes, using Corresponding_Record.
 232
 233    procedure Expand_N_Requeue_Statement          (N : Node_Id);
 234    procedure Expand_N_Selective_Accept           (N : Node_Id);
 235    procedure Expand_N_Single_Task_Declaration    (N : Node_Id);
 236    procedure Expand_N_Task_Body                  (N : Node_Id);
 237    procedure Expand_N_Task_Type_Declaration      (N : Node_Id);
 238    procedure Expand_N_Timed_Entry_Call           (N : Node_Id);
 239
 240    procedure Expand_Protected_Body_Declarations
 241      (N       : Node_Id;
 242       Spec_Id : Entity_Id);
 243    --  Expand declarations required for a protected body. See bodies of both
 244    --  Expand_Protected_Body_Declarations and Expand_N_Protected_Body for full
 245    --  details of the nature and use of these declarations. The second argument
 246    --  is the entity for the corresponding protected type declaration.
 247
 248    function External_Subprogram (E : Entity_Id) return Entity_Id;
 249    --  return the external version of a protected operation, which locks
 250    --  the object before invoking the internal protected subprogram body.
 251
 252    function First_Protected_Operation (D : List_Id) return Node_Id;
 253    --  Given the declarations list for a protected body, find the
 254    --  first protected operation body.
 255
 256    procedure Install_Private_Data_Declarations
 257      (Loc      : Source_Ptr;
 258       Spec_Id  : Entity_Id;
 259       Conc_Typ : Entity_Id;
 260       Body_Nod : Node_Id;
 261       Decls    : List_Id;
 262       Barrier  : Boolean := False;
 263       Family   : Boolean := False);
 264    --  This routines generates several types, objects and object renamings used
 265    --  in the handling of discriminants and private components of protected and
 266    --  task types. It also generates the entry index for entry families. Formal
 267    --  Spec_Id denotes an entry, entry family or a subprogram, Conc_Typ is the
 268    --  concurrent type where Spec_Id resides, Body_Nod is the corresponding
 269    --  body of Spec_Id, Decls are the declarations of the subprogram or entry.
 270    --  Flag Barrier denotes whether the context is an entry barrier function.
 271    --  Flag Family is used in conjunction with Barrier to denote a barrier for
 272    --  an entry family.
 273    --
 274    --  The generated types, entities and renamings are:
 275    --
 276    --  * If flag Barrier is set or Spec_Id denotes a protected entry or an
 277    --    entry family, generate:
 278    --
 279    --      type prot_typVP is access prot_typV;
 280    --      _object : prot_typVP := prot_typV (_O);
 281    --
 282    --    where prot_typV is the corresponding record of a protected type and
 283    --    _O is a formal parameter representing the concurrent object of either
 284    --    the barrier function or the entry (family).
 285    --
 286    --  * If Conc_Typ is a protected type, create a renaming for the Protection
 287    --    field _object:
 288    --
 289    --      conc_typR : protection_typ renames _object._object;
 290    --
 291    --  * If Conc_Typ has discriminants, create renamings of the form:
 292    --
 293    --      discr_nameD : discr_typ renames _object.discr_name;
 294    --        or
 295    --      discr_nameD : discr_typ renames _task.discr_name;
 296    --
 297    --  * If Conc_Typ denotes a protected type and has private components,
 298    --    generate renamings of the form:
 299    --
 300    --      comp_name : comp_typ renames _object.comp_name;
 301    --
 302    --  * Finally, is flag Barrier and Family are set or Spec_Id denotes an
 303    --    entry family, generate the entry index constant:
 304    --
 305    --      subtype Jnn is <Type of Index> range Low .. High;
 306    --      J : constant Jnn :=
 307    --            Jnn'Val (_E - <Index expression> + Jnn'Pos (Jnn'First));
 308    --
 309    --  All the above declarations are inserted in the order shown to the front
 310    --  of Decls.
 311
 312    function Make_Task_Create_Call (Task_Rec : Entity_Id) return Node_Id;
 313    --  Given the entity of the record type created for a task type, build
 314    --  the call to Create_Task
 315
 316    function Make_Initialize_Protection
 317      (Protect_Rec : Entity_Id) return List_Id;
 318    --  Given the entity of the record type created for a protected type, build
 319    --  a list of statements needed for proper initialization of the object.
 320
 321    function Next_Protected_Operation (N : Node_Id) return Node_Id;
 322    --  Given a protected operation node (a subprogram or entry body), find the
 323    --  following node in the declarations list.
 324
 325    procedure Set_Discriminals (Dec : Node_Id);
 326    --  Replace discriminals in a protected type for use by the next protected
 327    --  operation on the type. Each operation needs a new set of discriminals,
 328    --  since it needs a unique renaming of the discriminant fields in the
 329    --  record used to implement the protected type.
 330
 331 end Exp_Ch9;